Transcript File

SURFACE FINISHINGS
The art of treating the surface of building
materials with a suitable covering material to
make them weather resisting and decorative is
called surface finishing.
The covering material used for surface finishings
are called surface finishes which are plasters,
paints, washes etc.
PURPOSE
• To protect the surface from the effects of
weathering agencies.
• To provide a smooth surface.
• To provide pleasing appearance to the surface.
IMPORTANT TECHNICAL TERMS
•
Background :- The surface to which first coat of plastering is
applied is called background.
•
Dubbing out:- The filling the hollow spaces of the back
ground before applying the plaster is called dubbing out.
•
Finishing coat:- The final layer of the surface finish is called
finishing coat.
•
Hacking:- The process of making the background rough to
act as key for plastering is called hacking.
Important Technical Terms (-ctd-)
•
Gauging:- The mixing of various constituents of plaster is
called gauging.
•
Rendering coat:- The first coat of plastering is called
rendering coat.
•
Under coat:- The layer providing base for the application of
remaining coats is called under coat.
•
Floating:- The process of providing a finishing coat with a
float is called floating.
Important Technical Terms (-ctd-)
•
Peeling:- The removal of the plaster from the
background is called peeling.
•
Blistering:-The local swelling of a finished plastered
or painted face is known as blistering. This is due to
lack of adhesion of the plaster or paint with the
surface.
•
Cracking:-The development of angular fractures or
cracks in a plastered surface is called cracking. In
case of painting it indicates the presence of a soft
under coat.
•
Checking:-The longitudinal split in a painted or
plastered surface is known as checking.
Important Technical Terms (-ctd-)
 Chalking:-The dull and powdery appearance of a painted or
plastered surface is known as chalking. It indicates
insufficient or inferior binding material used in the paint or
plaster.
 Crazing:-The irregular development of hair like cracks on a
plastered surface is termed as crazing.
 Dado:-The special treatment provided to plastered walls at
their lower level usually in bathrooms is called dado. It is
provided up to one meter height from the floor level. It
may be consisting of rich cement mortar, glazed tiles etc.
Important Technical Terms (-ctd-)
 Skirting:- The special treatment provided to plastered
walls at their lower level usually in drawing and living
rooms of a building is called skirting.
It is provided up to 15cm height from the floor level.
It is usually consisting of the material which is used for
providing margin or boarder of flooring.
It is provided to protect the walls from water in case of
washing of floors
PLASTERING
The art of covering the surface of
masonry work with a suitable material is
called plastering.
PLASTERING
• A fine paste of mortar made by mixing cement with
sand or fat lime with sand or surkhi in addition to
sufficient quantity of water if called plaster.
• When cement is used as a binding material, the plaster
is called cement plaster and if lime is used as the
binding material, it is called lime plaster.
• An ideal plaster should be smooth, non absorbent and
washable. It should not be affected by weathering
agencies.
PLASTERING
• The finished surface of walls constructed in bricks or
stones are generally so coarse textured that they
provide unsuitable finish for the internal walls of
most of the buildings.
• These surfaces are rendered smooth by the
application of one or two coats of plaster. The
ceilings are also rendered smooth with plaster.
PLASTERING
• The object of external plastering is to cover the
surface to enable it to resist the effect of weathering
agencies. However, a good brick work made of
sound, well burnt bricks or neat stone masonry
constructed of durable stones does not require
external plastering.
• The object of internal plastering is to provide a
smooth surface in which dust and dirt cannot lodge
and to form a smooth surface for applying white or
color wash, distemper or paint.
TYPES OF PLASTERING
1. CEMENT PLASTERING
• The mix ratio of mortar in case of cement
plastering depends upon the nature of the work
to be plastered.
• For rich plastering work at sensitive places (e.g.
in side bathrooms, W.C. etc.), 1:3 cement plaster
mix is used. For general plastering of walls 1:5 to
1:8 cement plaster mixes are used.
CEMENT PLASTERING (-ctd-)
•
Preparing the surface
Before applying the plaster, the surface
should be prepared properly.
•
The joint of masonry are properly raked to a
depth of 10 to 15 mm to provide key to plaster.
•
The surface is then thoroughly wetted with
water, washed well and kept wet for six hours.
•
When the surface is ready, plaster is applied.
CEMENT PLASTERING (-ctd-)
• Applying the plaster
• Cement plastering may be applied in one or
two coats.
• In case of plastering of single coat, the mortar is dashed against
the prepared surface into a uniform thickness with the help of
trowel.
• Wooden screeds 7.5 cm wide and of required thickness of the
plasters are generally fixed vertically 2.4 to 3 m apart to act as
gauges guides in order to keep the plaster to the required
thickness. Careful plumbing should be done in fixing of these
screeds.
CEMENT PLASTERING (-ctd-)
• Surplus mortar is removed with the help of mason’s
straight edge and then the mortar is pressed well
with a wooden float so that mortar may fill in the
joints of the masonry.
• The surface is then finally polished with a trowel or
iron float.
• The thickness of this coat should not be more than
16 mm.
CEMENT PLASTERING (-ctd-)
• In case plastering is to be done in two coats the first coat is
applied as described above with the only difference that it is not
polished.
• Before applying the second coat, the first coat is allowed to set
but it would not become dry and it is also roughened with a
scratching tool to provide key to the second coat.
• The second coat is then applied in a thin layer not exceeding 3
mm in thickness within 48 hours.
• It is then well trowelled and rubbed perfectly smooth with the
help of a steel float. It is then allowed to set for 2 days and cured
for more than 7 days.
CEMENT PLASTERING (-ctd-)
• Suitability
• This type of plastering forms an ideal coating for
external finishings.
• It is also used for internal renderings of common as well
as important buildings.
• It is specially suited for damp conditions i.e. bathrooms,
etc.
2. LIME PLASTERING
• The proportioning of the ingredients of a lime
plaster is adopted according to the number of
coats to be applied.
• If the plaster is to be applied in one coat, 1 part
of lime to 1.5 parts of sand is used.
• If two coats are to be applied, the proportion
for the first coat is same as above while the
second coat consists of two parts of lime and
one part of sand.
LIME PLASTERING (-ctd-)
• If three coats are to be applied, the proportion
of the third coat consists of 4 parts of lime to
one part of sand.
• In actual practice, all the coats consist of 1
part of lime to 2 part of sand.
• Thickness of the lime plaster varies from
15mm to 20mm.
LIME PLASTERING (-ctd-)
•
Preparing the surface
The method of preparing the surface is same
as described in case of cement plastering.
LIME PLASTERING (-ctd-)
•
Application of first coat
•
It is applied by dashing the lime plaster with the help of
trowel against the wall surface between the screeds.
•
Plaster is pressed well in the joints.
•
Function of this coat is to fill all the irregularities of the
surface.
•
Average thickness of this coat is 10 to 12 mm. It is then
left to dry for 3 to 4 days.
LIME PLASTERING (-ctd-)
•
Application of second coat
•
Before applying this coat, the first coat is well washed
and scratched over with the edge of a trowel.
•
The second coat is then pressed against the wall with
mason’s trowel and rubbed with a straight edge.
•
Thickness of this coat is 6 to 10 mm.
LIME PLASTERING (-ctd-)
•
Application of final and finishing coat
•
This coat usually consists of fat lime which is called lime
putty.
•
It is applied on the second coat, made perfectly plain
and then rubbed first with wooden float and then with a
steel float to polish the surface,
•
It is about 3 to 6 mm in thickness.
•
It is allowed to dry for two days and then the surface is
cured for 7 to 10 days.
LIME PLASTERING (-ctd-)
• Suitability
This type of plastering is suitable for internal
renderings of buildings. But it is not commonly
adopted these days.
3. MUD PLASTERING
• The wall surface is first prepared as described in case
of cement plastering.
• The mud plaster is then evenly dashed against the
wall surface with a wooden float.
• After 24 hours, the surface is tamped. The function
of tamping is to compact the layer and to drive it
deep into the joints. It also helps to avoid
developments of cracks due to hollows.
MUD PLASTERING (-ctd-)
• After tamping, water is sprinkled slightly and the
surface is polished with a steel trowel.
• A thin wash of cow dung is then given and tamping is
done again at the places where small cracks have
formed.
• Finally the surface is given a wash of fine white earth
and cow-dung.
• Sometimes, surface is given a wash of fine earth, cow
dung and cement in proportion of 3 : 2 : 1.
MUD PLASTERING (-ctd-)
• Suitability
This type of plastering is done on walls of
temporary sheds and country side buildings.
4. STUCCO PLASTERING
• This is special type of plaster.
• Stucco is the name given to a decorative type of plaster
which provides an excellent finish like that with marble
lining.
• After preparing the surface, stucco plastering is applied
in three coats.
• Each coat should be permitted to dry thoroughly
before applying the next coat.
STUCCO PLASTERING (-ctd-)
•
For internal surface, the first coat also known as scratch coat
consists of lime plaster 12 mm in thickness.
• The second coat or brown coat consists of rich lime plastering in
10 mm thickness.
• The final coat or finishing coat consists of a mixture of very fine
lime and white ground stone ( marble or quartz), 3 mm in
thickness.
• It is carefully polished with a bag of linen containing moist chalk
in the first instance and then chalk and oil.
• The surface is then finally finished by rubbing it with only oil as
to make it smooth and bright.
STUCCO PLASTERING (-ctd-)
• For external surfaces, the first and second coats are
10 to12 mm thick and the finishing coat is 3 to 6 mm
thick.
• The proportion of ingredients for the first two coats
is 1 part of cement to 3 parts of sand with 10% by
weight of hydrated lime.
• The finishing coat consists of 1 part of cement and 2
pars of sand in which some coloring pigment is
added or colored cement is used.
STUCCO PLASTERING (-ctd-)
• Method of applying this plaster is same as
described in case of cement or lime plastering.
• Suitability
This type of plastering is suitable for external
as well as internal surfaces of buildings to
provide an excellent finish.
5. MOUGHAL PLASTERING
• It is generally applied in two coats of lime mortar by
mixing lime, sand and surkhi in the ratio of 4:3:1 along
with glue and powdered gull nut.
• The surface is well wetted and the second coat of
about 1.25 mm thickness is applied when the first coat
is hardened.
• The finished plastered surface is kept wet for 3 weeks.
MOUGHAL PLASTERING (-ctd-)
• Suitability
This type of plastering is suitable for internal
surfaces of high class buildings but it is not
commonly applied these days.
POINTING
• Final treatment with cement or lime mortar made to the joints of
the masonry to provide neat appearance is termed as pointing.
• The joint on the face of stone or brick masonry are roughly filled
in while the walls are being raised.
• They are after wards neatly finished off to make them water
tight.
• The joints thus finished, give a better appearance to surface and
prevent rain water from entering the interior of the masonry.
PURPOSE
1. To prevent the moisture and the rain water
from entering the interior of masonry
through joints and to make them durable.
2. To improve the appearance of the structure.
SUITABILITY
• Pointing is preferred to plastering under following
conditions.
1. When a smooth and even surface is not
essentially required.
2. Where it is desirable to exhibit to view the
natural beauty of the materials (bricks or stones)
used in construction.
3. When the workmen ship is neat and good.
TYPES OF POINTING
The selection of particular type of pointing
depends upon the types of bricks or stone
used and the appearance required..
TYPES OF POINTING (-ctd-)
1. Flat or flush pointing
• In this pointing, the mortar is pressed tightly and the
joints are filled up and made flush with the face of the
wall.
• This is the simplest type of pointing and is provided
extensively.
• It is economical and durable because it requires less
labor than all other pointing.
• It does not afford a lodging place for dust.
TYPES OF POINTING (-ctd-)
2. Struck pointing
• In this pointing the face of the mortar joint instead of
keeping it vertical, its upper side is kept about 12 mm
inside the face of the masonry and the bottom is kept
flush with the face of the wall as shown in fig 14.2.
• This pointing has a better effect of throwing rain water.
• This is also known as ruled pointing.
• This pointing is the best in ordinary circumstances.
TYPES OF POINTING (-ctd-)
TYPES OF POINTING (-ctd-)
3. Recessed pointing
• In this pointing the face of the mortar joint is
pressed inside by means of a suitable tool and is left
vertical instead of being made inclined.
• This pointing is provided when face work of good
textured bricks with good quality mortar is used.
TYPES OF POINTING (-ctd-)
4. V-pointing
• This type of pointing is provided by forming a vshaped groove inside the mortar of the joint with a
special tool (steel or iron jointer).
• This pointing is commonly recommended for brick
work in case of governmental buildings.
TYPES OF POINTING (-ctd-)
TYPES OF POINTING (-ctd-)
5. Weather pointing
• This is similar to V-Pointing but in this case
instead of pressing a v shaped groove inside, it
is provided by forming a v shaped projection
outside the wall’s surface.
• This pointing is generally recommended for
superior brick work.
TYPES OF POINTING (-ctd-)
6. Keyed or grooved pointing
• In this case, the joints are first filled up flush, and then
a circular piece of steel or iron is pressed in and rubbed
in the middle of joints.
• Grooved pointing has a big groove in the face than
keyed.
• Keyed pointing gives an attractive appearance to the
structure and is generally used for superior work.
TYPES OF POINTING (-ctd-)
TYPES OF POINTING (-ctd-)
TYPES OF POINTING (-ctd-)
7. Tuck pointing
• In this pointing, the mortar joints are filled with the
face of the wall. Then 6 mm wide and 3 mm deep
groove is immediately and carefully formed in the
centre of the joint and the groove is filled with or
tucked in with white lime putty.
• The lime putty is given a maximum projection of 6 mm.
• Tuck pointing has a neat attractive appearance. But the
lime putty is not durable and in due course of time
becomes defective.
JOINTS IN BUILDINGS
• The separations or planes of weakness
introduced at different locations in a building
are known as joints in the buildings.
• When joints are provided in a building,
reasonable care has to be exercised for the
location, design, detailing of joints and selecting
materials for forming and filling the joints.
JOINTS IN BUILDINGS
• All building materials expand or contract with change in temperature and
variation in moisture contents. Thus, major dimensional changes are caused
in structures due to expansion or contraction of materials used in their
construction.
• The magnitude of these changes varies with the type of material used.
• To overcome this problem, the large and multi-storied buildings may either
be constructed monolithically with heavy reinforcement to link each of their
component parts or they may be provided with a number of joints
• Joints are usually provided in large or multistoried buildings. But joints should
not be provided in shell structures and certain other rigid structures where
provision of joints interferes with the rigidity of structure.
TYPES OF JOINTS
1- CONTRACTION JOINTS
• The joints introduced in concrete structures to localize
shrinkage movements are known as contraction joints.
• The contraction joints are in the form of separations or
planes of weakness.
• The function of these joints is to localize shrinkage
movements which would otherwise lead unsightly
cracks.
TYPES OF JOINTS (-ctd-)
• Contraction joints may be of any of the following types:(a) Complete contraction joint
• In this type of contraction joint, the bond between the adjacent
sections of a structure may be broken completely by painting
one face with a bituminous material or by setting a layer of
waterproof paper or roofing felt against the face of the section
before casting the next adjacent section.
• These contraction joints are provided in thick sections of
concrete to localize shrinkage movements.
TYPES OF JOINTS (-ctd-)
(b) Partial contraction joint
• In this type of contraction joint, the reinforcement is
continued across the joint. Due to presence of
reinforcement, the movement at such joints is
usually very small.
• These contraction joints are provided in concrete
sections where structural stability is also required in
addition to localize shrinkage movements.
TYPES OF JOINTS (-ctd-)
(c) Dump joints
• In this type of contraction joint, a plane of weakness is
created by forming a groove in either or each of the
surface of concrete structure.
• The total depth of such a groove is one-third to onefifth of the thickness of the concrete section.
• These contraction joints are used more particularly in
thin sections of concrete such as floor slabs, roof slabs
etc.
TYPES OF JOINTS (-ctd-)
2- SLIDING JOINTS
• The joints provided between the two parts enabling their
movement freely in both the planes are known as sliding joints.
• These joints are usually formed by applying a layer of plaster to
one of the surfaces and finishing it smooth so as to act as seat of
the sliding joint.
• The seat is then allowed to be hardened and covered with the
required thickness of bituminous materials or otherwise treated
as specified to form a slip plane before the other portion is cast
on it.
TYPES OF JOINTS (-ctd-)
SLIDING JOINTS (-ctd-)
• The function of these joints is to enable freedom of
movement of the two parts in both the planes.
• These joints are used when variations in
temperature, moisture contents or loading result in
tendency for one part to move in a plane at right
angles to the plane of another part of a structure.
TYPES OF JOINTS (-ctd-)
3- CONSTRUCTION JOINTS
• The joints provided at locations where construction stops for any
reason and when their location does not coincide with that of
expansion or contraction joints are called construction joints.
• These joints are constructed in a similar manner as contraction
joints but these joints are not intended to accommodate
movement due to contraction.
• Every effort should be made to prevent movement occurring at
such joints.
• However, extra care may be taken to obtain a good bond
between abutting sections of concrete.
TYPES OF JOINTS (-ctd-)
CONSTRUCTION JOINTS (-ctd-)
• Since, cracks frequently develop at these joints as a result of stresses arising
from variations in temperature, moisture content or loading, therefore, it is
most desirable that construction joints should coincide with expansion or
contraction joints wherever possible.
• The function of these joints is to simplify the construction of a structure.
• Construction joints in floor should be located in the middle of spans of slabs,
beams or girders unless a beam intersects the girder at this point in which
case the joints in the girders are provided at a distance equal to twice the
width of beam.
• Adequate provision should be made for shear by use of inclined
reinforcement.
•
Joints in column should be made at the underside of the floor.
TYPES OF JOINTS (-ctd-)
4- EXPANSION JOINTS
• The joints provided to accommodate the expansion of
adjacent parts in a building are known as expansion joints.
• These joints essentially consist of a space between the
adjacent parts of a structure and may sometimes be provided
with the load transmitting devices between the parts.
• They are generally filled with expansion joint filler of approved
quality.
TYPES OF JOINTS (-ctd-)
EXPANSION JOINTS (-ctd-)
• The function of these joints is to accommodate the
expansion of adjacent parts of a building and relieve
the compressive stresses that may otherwise develop.
• These joints are provided in long masonry walls, roofs
and floors, roof or floor to wall joints, framed
structures etc. For spacing of these joints in different
locations, refer to table
TYPES OF JOINTS (-ctd-)
EXPANSION JOINTS(-ctd-)
• The design and location of joints usually depend upon the
type of structure, the method of construction and the
jointing materials available.
• The provisions of joints should be adequate to accommodate
all the dimensional changes caused by expansion and
contraction of materials used in the structure.
TYPES OF JOINTS (-ctd-)
EXPANSION JOINTS (-ctd-)
•
In case of masonry walls, the vertical control joints (expansion joints)
should be provided from top of the wall to the top of the concrete
foundations and not through the foundation concrete. The reinforcement
should not pass through such joints.
•
In case of masonry walls resting on pile foundation, the vertical control
joints should be taken up to the top of grade beam i.e. concrete cap over
the piles without making use of any reinforcement passing through the
joints.
•
In case of reinforced framed structures, the vertical control joint between
any two columns should extend from top of the column to the top of the
pedestal provided over the RCC footing.
S.
No.
1
2
Item and Description
Walls:
(a)Load bearing walls with cross walls at
intervals. Traditional type of one-brick
thick or more.
Spacing of Expansion Joints
30 m intervals.
(b)Walls warehouse type construction
(without cross-walls)
Expansion joints in walls at 30 m
maximum intervals. (If the walls are
panel walls between columns at not
more than 9 m centers, no joints are
necessary). Control joints over centre
of openings may be provided at half
the spacing of expansion joints.
Chajjas, balconies and parapets.
6 to 12 m intervals.
S.
No.
3
4
5
Item and Description
Spacing of Expansion Joints
Roofs :
(a)Ordinary roof slabs of RCC
protected by layers of mud phuska or
other insulating media in framed
construction.
20 to 30 m intervals and at
changes in direction as in L, T, H
and V shaped structures.
(a)Thin unprotected slabs.
15 m intervals.
Frames :
Joints in structure through slabs,
beams, columns etc, dividing the
building into two independent
structural units.
Corners of L, T, H and V shaped
structures at 30 m intervals in
long uniform structures.
Coping
Corresponding to joints in the
roof slabs.
DOORS
The arrangements made to provide free and
easy access inside and outside the rooms of a
building are called Doors.
Whereas, the opening provided in the boundary
wall of a building for entrance and exist is
known as Gate.
DOORS (-ctd-)
• Doors are generally made of timber. They may also be
consisting of plywood, wire gauge, frame work of steel etc.
• They may be having one or two leaves or shutters.
• The doors with one shutter are known as single leafed doors.
Such doors are used for small openings.
• The doors having double leaves or shutters are called double
leafed doors. Such doors are used for large openings.
LOCATION OF DOORS
• Doors should be located in such a way that free
movement in and out of the rooms of a building is
ensured. Doors should be properly placed in the corner
of a room.
• In case the room is to be provided with more than one
door, they should be located in the opposite walls to
have a good ventilation in that room.
IMPORTANT TECHNICAL TERMS
• Frame:- An enclosure to provide support for door or window
shutter is called frame. It is made from the well seasoned wood.
Head and sill are morticed to take the tenon formed at the ends
of vertical posts. Bamboo pins are used to hold shoulders and
the tenons tightly.
• Head:-The top horizontal member of a door or window frame is
called head.
• Sill:- The bottom horizontal member of a door or window frame
is called sill.
• Posts:- The vertical side members of a door or window frame are
called posts.
IMPORTANT TECHNICAL TERMS (-ctd-)
•
Shutters:- The planks, framed, paneled or otherwise which fit
in a door or window frame are known as shutters. They are
hung to the frame by means of hinges.
•
Styles or stiles:- The vertical side members of frame-work of a
shutter are called styles. The style which is hung or hinged to
the frame is called a hanging or hinged style. Whereas the
style which is not hung or hinged to the frame is called a
meeting style.
•
Top rail:- The topmost horizontal member of the frame-work
of a shutter is known as top rail.
•
Lock rail:- The middle horizontal member of the frame-work of
a shutter where lock sliding bolt is fixed is called lock rail.
IMPORTANT TECHNICAL TERMS (-ctd-)
•
Bottom rail:- The lower most horizontal piece or member of the framework of a shutter is known as bottom rail.
•
Mullion:- The vertical member running through the middle of frame-work
of a shutter is called mullion or muntin.
•
Jambs:- The vertical faces of a door or window opening which support the
frame of a door or window are called jambs.
•
Reveal:- The portions of a door or window opening extending beyond the
frame towards the face of a wall are called reveals.
•
Sash bars:- The light members of the frame-work which carry the glass
panes within a shutter or frame work are known as sash bars.
IMPORTANT TECHNICAL TERMS (-ctd-)
•
Panels:- The small wooden members which are
provided between the rails of a shutter or framework are called Panels.
•
Rebate:- Depression or cut in the frame of a door or
window to receive the shutters is called rebate.
•
Horns:- The projections of head or sill of a door or
window frame are known as Horns. These are
generally embedded in the masonry to increase their
fixing strength.
•
Louver:- The inclined boards fixed in a frame-work
are called Louvers.
IMPORTANT TECHNICAL TERMS (-ctd-)
•
Transom:- The horizontal dividing member in a window or
door frame provided with fan light is called Transom. It acts
a head of the door or window frame and sill of the fan light.
•
Stops:- The timber pieces fixed to the door or window
frame on inside to prevent the shutters from damaging the
plaster of jambs when fully opened are called stops.
•
Chocks:- The timber pieces hinged to the window or door
frame on outside to prevent the shutters from closing under
the effect of heavy wind are called chocks.
FIXING OF A DOOR FRAME IN A WALL
• A door frame is fixed in the masonry by hold fasts built into the walls with
cement mortar (1: 5).
• The hold fasts are made from 3.7 cm x 0.6 cm flat, bent at both ends One end
of each hold fast is fixed on the side of the door frame and its other end is
built into the masonry.
• The horns provided at the head and sill or in between, are also built into the
walls.
• Now-a-days, sill is not provided in case of a door frame since it causes
obstruction to the free movement and does not permit easy cleaning and
washing of floors.
• Before fixing a door frame, its sides coming in contact with masonry, are
painted with two coats of a wooden-preservative (generally coal tar). The
other sides of the frame are generally given a priming coat.
TYPES OF DOORS
1. Ledged and battened doors
• These are the simplest type of doors.
• They consist of battens (each 15 cm wide and 0.8 to 1.8 cm
thick) which are screwed to three horizontal members called
ledges.
• Top ledge is 10 cm x 3.2 cm in cross-section, middle and bottom
ledges have section of 17.5 to 20 cm x 3.2 cm.
• Battens are generally tongued and grooved.
• These doors are mostly used for narrow openings in temporary
houses where appearance is not the main consideration.
1- Ledged and Battened
Ledged
2- Battened and Braced Door
2. Ledged, battened and braced doors
• This type of door is similar to a ledged and battened door except
that they consist of ledges and battens which are strengthened
with the help of diagonal members known as braces.
• The width of braces varies from 10 to 15 cm and thickness is 3.2
cm.
• The inclination of the braces should be kept towards the side of
the shutter to be hinged to the frame as shown in fig. 10-3.
• These doors can be used for comparatively large openings in
ordinary houses and in places where appearance is not so
important.
3. Framed, ledged, battened and braced doors
• This is a better and strong type of door.
• They consist of two stiles, three rails and two braces forming the frame-work
of each leaf (shutter) to which he battens are fixed.
• The frame-work is made with mortice and tenon joints.
• The top and bottom rails and the stiles have full thickness while the middle
(lock) rail and braces are thinner in section to allow the battens to pass over
them and finish flush with the top and bottom rails.
• The battens should butt into the rebate in the top and bottom rails.
• These shutters are hung to the frame by means of butt hinges.
• These doors are mostly used as external doors in ordinary residential
buildings, shops etc.
3- Framed, Ledged, Battened
and Braced Door
4- Framed and Paneled Door
4. Framed and paneled doors
• This is the most common type of door.
• They are made in different designs but their principle for construction is same
as in other doors.
• They consist of frame-work of styles, rails and muntins or mullions of same
thickness.
• The space between them is filed with panels. The vertical styles are
continuous from top to bottom and rails are jointed to the styles.
•
On inside of the styles and rails, grooves are made to receive the panels
which may be of raised or flush type.
• These shutters are hung to the frame by means of butt hinges.
• These doors are mostly used in residential and other buildings as internal
and external doors.
5. Paneled and glazed doors
• The construction of this type of door is similar to a framed and paneled door
but in such doors glass panes are fixed.
• In these doors, instead of wooden panels in their top portions, sash bars to
receive the glass panes are used.
•
Sash bars are equal in thickness to the full thickness of the shutter, with 2.5
cm with and having 1 to 3 cm rebate according to the size of the doors.
• The size of the rebate is generally 1.6 cm x 0.6 cm. Each glass pane is secured
in position by small nails and is bedded with the help of lime-putty.
• It may be either 1/3rd glazed at top and2/3 paneled at bottom, or 2/3 glazed
at top or 1/3 panelled at bottom.
• These doors are mostly used in public buildings, hospitals, colleges, offices
and also in residential buildings.
5- Panelled and glazed Door.
6. Flush doors
• These doors are made with plywood and give better appearance.
• They are solid and semi-solid door and are constructed and finished in many
ways.
• The inner core is either framed or laminated. The later makes a more solid
and lasting door.
• These doors do not catch dust and are easy to clean.
• With the production of plywood in large quantities, flush doors are becoming
more and more popular these days.
• These doors are mainly used as internal doors in residential buildings,
restaurants, public and other important buildings.
(a) Framed Flush Door
(b) Solid Laminated Flush Door.
7. Louvered doors
• These doors are similar to glazed and paneled doors. But in
these doors, the spaces between the rails and stiles are filled
with series of wooden members called louvers.
• The louvers are fixed into the stiles or made movable.
• In order that they may be effective and economical, are fixed at
an angle of 45 degree.
• These doors allow free passage of light air and secure privacy
and safety. But they collect dust easily and are difficult to clean.
• These doors are mostly used in school, workshops or at place
where sufficient privacy is required besides admitting air and
light freely.
7- Louvered Door
8- Revolving Door
8- Revolving doors
• These doors consist of four shutters, arranged diagonally,
revolving on a common vertical axis.
•
Paneled, glazed or both types of shutters may be used for these
doors. They allow entrance on one side and exit on the other
side.
• These doors are used where there is constant foot traffic of
people coming in and going out of an entrance in public
buildings such as offices, banks, restaurants, hotels, theatres,
and other public buildings.
• They are also used in hill stations to prevent strong wind blowing
inside the building directly.
9- Sliding Doors
• These doors consist of single or double steel
or wooden shutters.
• They slide into the pockets provided in the
masonry wall.
• These doors are commonly used for
workshops, garages and on windows in shops
etc.
9- Sliding Door
10- Collapsible Doors
• These doors consist of frame work of rolled steel sections and
are provided with rollers at bottom which roll on rails.
• These doors are rolled when they are to be opened or collapsed.
• Flat iron pieces are used cross wise and are fixed to vertical flat
iron pieces at 12 to 15 cm centre to centre so as to form
parallelograms. When pushed, the parallelograms get collapsed.
• These doors are used in public buildings such as banks, railway
stations, sheds, godowns, workshops etc.
10- Collapsible Door.
11- Rolling Steel Doors
• These doors are generally made of thin corrugated steel plates (
or sheets) which roll up on a roller or drum.
• The shutter slides in grooves in the side walls.
• The shutter may be counter balanced by sprigs so that it can be
easily raised on lowered by hand.
• These doors are sufficiently strong and may be safely used in
exposed places.
• These doors are mostly used for main entrance of shops,
showrooms, and garrages
11- Rolling Steel Door
12- Wire-gauged Door
12- Wire-gauged doors
• These doors are normally hung on the same chowkhat (frame)
as other door and window shutters of the frame.
• The thickness of the frame is increased suitably to cut the rebate
for the wire gauged shutters.
• These doors allow free passage of the air and light and at the
same time do not allow entrance of flies and mosquitoes inside
the rooms of a building.
• These doors are mostly used in kitchens and dining rooms of
residential buildings
FLOORING
TYPES OF FLOORS
Normally the following types of floors are generally
used:
• Brick floor.
• Earth floor.
• Cement concrete floor.
• Mosaic floor.
• Tile floor.
• Marble floor.
• Wooden floor.
MATERIALS FOR FLOORING
The materials used for Ground floor
construction are:
• Stones.
• Bricks.
• Concrete.
• Marble.
• Chips.
• Asphalt.
FACTORS AFFECTING SELECTION OF FLOORS
1- INITIAL COST
• The cost of floor covering is the most important thing.
• The expensive types of floor coverings are marble and
teerrazzo (chips).
• Tiles and asphalt are less expensive whereas concrete and
brick are the cheapest and are commonly used.
2- APPEARANCE
• Co lour, texture and architectural beauty are the factors taken
into consideration.
FACTORS AFFECTING SELECTION OF FLOORS
( -CTD- )
3- DURABILITY
• Resistance to wear and tear is an important factor for a floor covering.
• Resistance to temperature changes, humidity, disintegration and decay
has alsoto be taken into account.
• Tiles, marble and concrete floor covering offer good resistance to these
factors. Wherever heavy floor traffic is not anticipated bricks and wood
blocks can be used.
4- CLEAN LINESS OF FLOOR
• A floor should be non absorbent and capable of being easily cleaned.
• All joints should be simple so that they can be made water tight as
possible.
• Glass strips used for making panels, should not be more than 16 sq. ft. i.e.
(4`x4`).
FACTORS AFFECTING SELECTION OF FLOORS
( -CTD- )
5- DAMPNESS
• Moisture should not penetrate in the floor.
• They should be completely water tight.
• Wood, Rubber are not suitable in damp places,
whereas tiles, bricks, concrete and Terrazzo is
suitable for use on flooring which are subjected to
dampness.
6- INDENTATIOIN
• Marks, depression due to furniture legs or ladies
shoes should not make any impression on the floor.
FACTORS AFFECTING SELECTION OF FLOORS
( -CTD- )
7- NOISELESSNESS
• This is not an important factor for ground floor constructions,
but it should be noiseless when traveled over.
• Rubber coverings and cork covering are most suitable.
8- MAINTENANCE
• For keeping floor in perfect condition it is necessary to clean,
repair and apply any other treatment from time to time.
• Marble and concrete floors require less repair whereas wood
blocks, need frequent maintenance.
• Concrete surfaces can not be repaired easily while tiles can
be replaced quickly.
CONSTRUCTION OF FLOORS
1- BRICK FLOORING
• Brick flooring is commonly used.
• The filling over which this floor is to be laid should be well compacted.
• The level of the flooring being known, the filling is excavated the desired
depth.
• Generally two types of beds are provided.
• In the first type, after excavation the surface is leveled and a layer of 3//
sand is spread over which a course of bricks is laid.
• In the second type, a lean cement concrete (P.C.C), one part of cement, 6
parts of sand and 18 parts of aggregates of 10 to15 cms in thickness is laid
on the compacted bed.
• Flat brick flooring is laid into1:6 C/S mortar over a bed of ¾ // thick
cement sand mortar.
• Bricks on edge flooring are laid into1:6 C/S mortar over a bed of ¾ // thick
C/S mortar.
CONSTRUCTION OF FLOORS ( -CTD- )
2- CEMENT CONCRETE FLOORING
• This type of floors are most commonly used both in
residential and commercial buildings.
• The two components of a concrete floor are Base &
Wearing surface (top surface).
• The flooring can be constructed either monolithic or
non-monolithic.
• In monolithic floors, a base layer is laid and then
immediately a concrete topping is provided and in
non-monolithic the topping is laid after the base has
set.
CONSTRUCTION OF FLOORS ( -CTD- )
DISADVATAGES OF MONOLITHIC FLOORS
• The topping is likely to get damaged due to
subsequent building operations.
• It is likely to develop hair-like cracks on account of
small settlements which may occur in the base course
immediately after it is laid.
• When the surface of the topping gets damaged, it is
very difficult to repair it.
• The progress is slow since the topping can be laid
only after the base course has sufficiently set to allow
the workmen to lay the top layer.
CONSTRUCTION OF FLOORS ( -CTD- )
CEMENT CONCRETE FLOOR DETAILS
• Topping is laid in panels over a base thickness
which varies 1// to 3//.
• If the thickness is 1-1/2// then it can be laid in
single layer and if it is exceeding then it is laid
in double layer.
• To avoid cracks due to shrinkage, the area of a
panel is restricted to 4/ x 4/ (i.e. 16 sq. ft.).
CONSTRUCTION OF FLOORS ( -CTD- )
3. MOSAIC OR TERRAZO FLOORING
• The base for terrazzo floor is of plain cement concrete (1:2:4).
• The topping shall not be less than 3/8// thick and shall be laid with a
bottom layer of cement concrete (1:2:4).
• The total thickness of topping of cement concrete should mot be less
than 1-3/8//.
• Normally 2// thickness is used, 1-1/2// concrete (1:2:4) and ½// mosaic.
• The mosaic topping shall consist of one part of cement (including15%
to30% marble powder) and two parts of marble chips.
• The mosaic topping shall be laid while the bottom concrete is still
fresh preferably on the next day or after 24 hours to have better
bond.
• The surface should be rough to get better bonding.
CONSTRUCTION OF FLOORS ( -CTD- )
4. TILE FLOORING
• Tiles of various shapes, sizes, thicknesses, color and surface
finishes are manufactured for used as surface covering for
floors.
• Floorings tiles are set on the concrete base with mortar.
• Special bedding made up of asphalt or portland cement is
available for use over concrete base.
• The concrete bedding is generally 5// thick and is laid evenly
with a slight rough surface at the top.
• After a period of 2 to3 days, a mortar layers of 1:1 mix is
spread on the concrete bed and the tiles are set evenly with a
thin a thin paste of cement applied to their sides.
CONSTRUCTION OF FLOORS ( -CTD- )
• They are slightly topped till the cement comes out
through the joints to the top surface.
• This extra cement is wiped off and the joints are
cleaned.
• After2 to3 days, these joints are rubbed to chip off all
the projecting edges or surfaces.
• The whole surface is then polished with a very soft
carborundum stone.
• Finally the surface is washed with soap. If the tiles
have glazed surfaces then this rubbing process is not
suitable.
CONSTRUCTION OF FLOORS ( -CTD- )
5. GLASS FLOOR
• Glass floors are used wherever it is desired to admit light into
the basements through the upper floor.
• The glass blocks are fitted within the frames of various
thicknesses to transmit light at an angle to the farther areas in
a room.
• Structural glass is available in the from of tiles or slabs and its
thickness ranges from 12 to 30 millimeters.
• The framework is spaced closed apart so the glass can
withstand loads coming over it. Glass flooring is not commonly
used.
CONSTRUCTION OF FLOORS ( -CTD- )
6. ASPHALT FLOORING
• Asphalt mastic is a mixture of fine aggregates (sand), natural or
artificial asphalt and coarse aggregates.
• It can be mixed hot and laid in continuous sheets or pressed into
blocks which can be used as flooring.
• It can also be mixed with a mineral oil and asbestos and applied
cold.
• While heating, the asphalt is stirred thoroughly so that the layer
at the bottom may not get burnt, when the whole quantity is
fused, sand or aggregates equal to twice the volume of asphalt is
added gently and mixed thoroughly. This mixture is then ready for
laying.
CONSTRUCTION OF FLOORS ( -CTD- )
7. WOODEN FLOORING
• This type of floor construction is not
extensively used but is popular for special
purpose floors, e.g. in auditorium, hospitals.
• Wooden flooring should have a concrete base
or should rest on joists spanning across walls
which are constructed at suitable interval.
• For the fixing of wooden floors on concrete
slabs, longitudinal railing strips are provided.
ROOFS
The covering provided over the top of an
enclosure made for a building to keep out the
sun, rain, wind and to protect the interior
from exposure to the weather is known as
roof.
ROOFS (-ctd-)
• A roof usually consists of frame work provided with a suitable covering at its
top.
• A good roof is as essential as a safe foundation of a building.
• Roofs must, therefore, be well designed and constructed to meet the
requirements of different climates and covering materials locally available.
• The form of construction of a roof is governed by the plan of a
building, span, the type of covering material locally available and
the architectural appearance required.
• The roof covering to be provided should be economical and
most suitable according to the nature of the building.
CLASSIFICAION
• Sloping, pent or pitched roofs
• Flat or terrace roofs
(Sloping roofs are suitable for the area where rainfall and
snowfall are heavy, whereas, flat roofs are suitable for the area
where rainfall is meager i.e. of low intensity, and there is no
snowfall)
• Shelled roofs
• Domes
TYPES OF SLOPING ROOFS
Shed Roof
Hipped Roof
Gable Roof
Gamberal Roof
TYPES OF SLOPING ROOFS (-ctd-)
1. Shed Roof:- A slopping roof having slope only in one direction
is called a Shed Roof. This is the simplest type of sloping roof
and is used for smaller spans.
2. Gable Roof:- A sloping roof having slope in two directions is
called a Gable Roof. This type of sloping roof is used for larger
span.
3. Hipped Roof:- A sloping roof having slope in four directions is
called Hipped Or Hip Roof. This type of sloping roof is mostly
used for buildings in hilly area.
4. Gambrel Roof:- A sloping roof having slope in two directions
with a break in the slope is known as Gambrel Roof. This type
of sloping roof is mostly used for buildings in hilly area.
Mansord Roof
Saw Tooth or North Light Roof
TYPES OF SLOPING ROOFS (-ctd-)
5. Mansord roof:- A sloping roof having slope in four
directions with a break in slope is known as Mansard
Roof
6. Saw tooth or north light roof:- A sloping roof
having glazing fixed on the steep sloping sides of the
roof is called Saw Tooth Or North Light Roof. This is
generally used in factories where more light is
required.
IMPORTANT TECHNICAL TERMS
Ridge:- The highest point or line of a sloping roof where the two
opposite slopes meet is known as ridge.
Ridge piece:- A horizontal piece of timber which runs the highest
level (bridge) of a sloping roof is called ridge piece.
Eaves:- The lowest edges of the surfaces of a sloping roof are called
eaves.
Eave’s board:- A wooden board fixed along the eaves at the end of
common rafters is known as eaves board or facia board.
Gutter is usually supported at eaves board.
IMPORTANT TECHNICAL TERMS (-ctd-)
Rafters:- The members which support the covering material of a
sloping roof are called rafters.
Hip:- The line of intersection of sloping surfaces of a roof forming
an external angle exceeding 180° is known as hip.
Hip rafter:- The rafter lying along the hip in a sloping roof is
termed as hip rafter.
Valley:- The line of intersection of two sloping surfaces of a roof
forming an external angle less than 180° is known as valley.
Valley rafter:- The rafter lying along the valley in a pitched roof is
known as valley rafter.
IMPORTANT TECHNICAL TERMS (-ctd-)
Jack rafter:- The short common rafters which run from a hip rafter
to the eave of a sloping roof are called jack rafters.
Common rafters:- The members supporting the battens or
boardings under the covering of a sloping roof are known as
common rafters.
Gable:- The end of a sloping roof finished in a vertical triangle is
called gabled end or gable.
Barge:- The finished edge of slating or tiling over-hanging a gable
wall is called barge.
Barge board:- Wooden planks fixed to the ends of the common
rafters projecting beyond the gabled end of a sloping roof is
called a barge board.
IMPORTANT TECHNICAL TERMS (-ctd-)
Purlins:- The wooden or steel members laid horizontally to support the common
rafters of a sloping roof are called purlins.
Cleats:- The pieces of timber or angle-iron which are nailed or screwed (for
timber), riveted or welded (for angle-iron) on the trusses, to support the
purlins are known as cleats.
Battens:- The pieces of wood which are directly nailed to the common rafters
are called battens. The roof coverings are directly laid over battens.
Pitch:- The inclination of the side of a slopping roof to the horizontal surface is
called pitch of the roof. It is usually expressed as the ratio of the rise to the
span or in degrees.
Truss:- A frame work of members arranged in triangles is called a truss.
STAIRS AND STAIR CASES
• A series of steps which provides access from one
floor to another is called a stair and the part of the
building accommodating the stair is known as stair
case.
• A stair may be constructed with steps either rising
continuously or with a break in the form of landing
in between.
• All the steps should be so designed and constructed
that up and down movements from one floor to
another can be made with ease, comfort, quickness
and safety.
STAIRS AND STAIR CASES (-ctd-)
• The stairs may be consisting of any suitable material such
as timber, bricks, stones, steel, reinforced cement concrete
etc.
• The provision of a stair in a building is essential for the
movements of inmates from one floor to another floor or
roof of that building.
• Now-a-days, in most modern residential and public
buildings of multi-storey nature, a lift system is provided for
convenience and quick movements of the users from one
floor to the other. In such buildings too, a stair is essential
for the movements of the users in case of failure of the lift
system due to some mechanical defect or non-supply of
electric power.
IMPORTANT TECHNICAL TERMS
Step:- The combination of a tread and a riser supported by a string is called a
step.
Tread:- The horizontal top surface of a step on which foot is placed while going
up or coming down a stair is known as tread.
Riser:- The vertical face of a step is called riser.
Going or run:- The horizontal distance between any two adjacent risers in a stair
is called going or run.
Rise:- The vertical distance between any two adjacent treads in a stair is called
rise.
Bull-nose step:- The step with one or both ends rounded is known as bull nose
step. This type of step is generally provided at the bottom of a flight and is
always projecting beyond the face of the newel post.
IMPORTANT TECHNICAL TERMS (-ctd-)
Nosing:- The projecting edge of a tread beyond its riser in a step is called nosing.
The line joining nosing of all steps in a flight is known as line of nosing.
Pitch or slope:- The angle between the line of nosing and the floor or landing is
called pitch or slope of a stair.
String or stringer:- The inclined support to which the ends of treads and risers of
a stair are fastened is called a string or stringer.
Hand rail:- As inclined member at a convenient height projecting above steps of
a stair to provide assistance and safe-guard to the users is called hand rail.
Balusters:- The vertical members provided in between the steps and the hand
rail are called balusters. These members act as intermediate supports to
the hand rail.
Newel or newel post:- The posts provided at the bottom, top and all the turning
points in a stair to support the hand rail are known as newels or newels
posts.
IMPORTANT TECHNICAL TERMS (-ctd-)
Soffit:- The under surface of a stair is called soffit.
Flier:- A step of uniform width is called flier. This type of step is rectangular in plan. Such steps
are always preferred even at turning points of a stair as they are safe for quick
movements of the uses.
Winder:- A step of non-uniform width is known as winder. This type of step is usually triangular
in plan. Such steps are only provided for changing the direction of a stair and should be
avoided as far as possible since they are dangerous for quick movement of the users.
Landing:- The horizontal platform provided in between any two flights of a stair is called landing.
The landing which provides 90° turn in the layout of a stair is known as quarter space
landing and if the turn is through 180°, it is called half-space landing
Flight:- A series of steps without any break in between is known as flight.
Head room:- The height between the line of nosing to the soffit of a flight or ceiling of roof
immediately above is called head room.
Width of a stair case:- The width of enclosure accommodating the stair in a building is called
width of stair case. It depends upon the layout and width of the stair.
REQUIREMENTS OF A GOOD STAIR
• It must be well designed so as to provide maximum
comfort, ease and safety.
• It should be centrally located in a building.
• All the steps should have uniform width and height
• The pitch or slope of a stair should neither be more
than 40° nor less than 24°.
• The width of a stair must not be less than 0.85 m in any
case.
REQUIREMENTS OF A GOOD STAIR(-ctd-)
• The maximum number of steps in a flight should not be more
than 15.
• The head-room must not be less than 2.1 m vertically or 1.5 m at
right angles to the line of nosing.
• The height of the hand rail should neither be more than 0.85 m
nor less than 0.75m measured vertically from the line of nosing
to the top of hand rail.
• It must be constructed of sound materials.
• It should have good workmanship.
• It must be properly ventilated and lighted.
PRINCIPLES TO BE OBSERVED WHILE PLANNING
AND DESIGNING A STAIR
1.
Relation between going and rise of a step
•
•
•
2 x Rise + Going in cm = 55 to 60 cm
Going x Rise, both in cm = 400 to 430 cm2
While designing steps, take 30 cm going and 14 cm rise as a standard value. For
each 2.5 cm subtraction from going, add 1.2 to 1.3 cm to the rise.
•
The following dimensions of going and rise are generally used for different
buildings:Residential buildings = 25 cm x 16 cm
Public buildings such as theatres, colleges, banks etc
=27 cm x 15 cm or 30 cm x 14 cm.
Industrial buildings
= The going should not be less than 25 cm
and rise not more than 19 cm.
•
It should be noted that the rules given above only act as guide but the actual
dimensions of going and rise depend upon the space available, height of the
building and layout of the stair.
PRINCIPLES TO BE OBSERVED WHILE PLANNING
AND DESIGNING A STAIR
2. Pitch of the stair:- The pitch or slope of the stair should not be
more than 40° and should not be less than 25° for comfortable
ascend and descend.
3. Width of stair:- The width of a stair must not be less than 0.85 m
so that a person going up can pass a person coming down
without any difficulty. The minimum width of stair in a
residential building should be 1.05 m whereas in case of a public
building, a minimum width of 1.5 m is desirable.
4. Length of flight:- The number of steps in a flight should not be
more than 15 otherwise it becomes difficult to move up and
down the flight. The minimum number of steps in a flight
should be 3.
PRINCIPLES TO BE OBSERVED WHILE PLANNING
AND DESIGNING A STAIR (-ctd-)
5. Width of landing:- The width of landing should not be less than
the width of its stair case.
6. Head room:- An adequate head-room must be provided. It
should not be less than 2.1 m.
7. Winders:- They should be avoided as far as possible. But they
are to be provided when the area of staircase is limited. In such
case, winders should be placed at the lower end of a flight. In a
quarter space i.e 90° turn, only three winders should be
provided.
8. Hand rails and balustrades:- A stair should be provided with a
hand rail along with balustrades to provide assistance, comfort
and safety to the users. The height of hand rail should neither
be more than 0.85 m nor less than 0.75m.
PRINCIPLES TO BE OBSERVED WHILE PLANNING
AND DESIGNING A STAIR (-ctd-)
9. Materials:- The stair should be constructed from sound
materials preferably of fire resisting quality. It should
be constructed of R.C.C. according to building bye-laws
being followed in the locality.
10. Location:- The staircase should be located in such a
position that it is easily and quickly approached. A
central position in a building would be ideal. Both light
and ventilation should be available especially at turning
points. In a residential building, the stair should be
located near the main entrance and screened from
outside for privacy. In public buildings, it should
preferably be located obvious from the main entrance.
CLASSIFICATION OF STAIRS ACCORDING TO
THEIR LAYOUT
1- Straight flight stairs:- The stair which rises from one floor to
another in one direction is known as straight flight or simply
straight stair (see fig. 2 a). This type of stair may be
constructed with or without landing. This type of stair is only
suitable for a long and a narrow staircase.
2- Quarter turn stairs:- The stair which turns through 90° either
to the left or to the right is known as quarter turn stair (see
fig. 2 b & c). This type of stair may be provided with winders
as shown in fig. 2 (b) or with a quarter-space landing as shown
in fig 2(c). This type of stair is suitable where the width
staircase is more but it has got limited length.
CLASSIFICATION OF STAIRS ACCORDING TO THEIR LAYOUT
3- Half turn stairs
The stair which turns through 180° is known as half turn stair (see fig. 2 d &c). In such
stairs, the adjacent flights are in opposite directions separated by half-space landings,
two sets of winders or two quarter space landings according to the space available.
•
Half turn stairs are further classified into the following two types:(a) Dog-legged stairs:- A half turn stair with no space between its flights is known as
dog legged stair (see fig. 2 d).
This type of stair is suitable where the width of
the stair case is limited and is commonly used for single or double storied modern
buildings.
(b) Open well stairs:- A half turn stair with a space (called well) between its flights is
known as open well stair (see fig. 2 e and f). This stair is also known as an open newel
stair when the well left between the flights is of rectangular shape see fig. 2 (e). If the
space for this type of stair is limited, a short flight is introduced on the narrow side of
the well with two quarter space landings as shown in fig. 2 (f).This type of stair is
suitable for multi-storied buildings as in this case the well allows for top lighting.
CLASSIFICATION OF STAIRS ACCORDING TO THEIR LAYOUT
(-ctd-)
4. Geometrical stairs: A half turn stair in which the dwell is of curved shape
between the forward and backward flights is called geometrical stair (see fig.
2 g). In this type of stair, the change in direction is obtained by winders. It
provides easy turning but is tiresome as it is generally without landing. This
type of stair is suitable for single or double storied buildings.
5. Circular stair:- The stair which is provided in a circular stair case is called
circular stair (see fig. 2 h). In this stair, the strings and the hand rails are
continuous and the change in direction is obtained by winders. All the steps
may be supported by a newel at the centre or there may be a circular well
hole. A circular stair having all is steps radiating from a central newel is
known as spiral stair. This type of stair is suitable when a limited space is
available for the stair case. Iron spiral stairs are very suitable for back door
entrance as they occupy very little space.
6. Bifurcating stairs:- This stair having its bottom flight wide which is divided into
two narrow flights at the landing at right angles in the opposite direction is
called a bifurcating stair (see fig. 2 i). This type of stair is suitable for public
buildings, assembly halls, railway foot bridges etc.
MAINTENANCE OF BUILDINGS
• The art of up keeping the different parts of buildings
in their best conditions to ensure neat appearance
and a fair life of service of those parts is called
maintenance of buildings.
• Maintenance of buildings may include cleaning
overhauling, general repair and replacement of
defective parts and special repair of defects
occurring due to their poor design and workmanship.
• The object of building maintenance is to ensure neat
appearance and stability of the building
CLASSIFICATION OF BUILDING
MAINTENANCE JOBS
Maintenance jobs of building are divided into
following two categories
1. Routine maintenance
2. Special Repair
(a) ROUTINE MAINTENANCE
Def: The day to day or thorough repairs which are
carried out in buildings after specified periods are
known as routine or periodic maintenance
Explanation: Routine maintenance of buildings includes
the following items of work
• Repair of damaged plaster surface
• White washing and colour washing
• Distempering
• Painting of timber and steel surface
• Repair to damaged part flooring
ROUTINE MAINTENANCE (-ctd-)
•
•
•
•
•
Removal stains from concrete and terrazzo floor
Re-polishing a terrazzo and mosaic flooring
Repair to worn out timber floor polishing and waxing
Replacement of glass panes
Replacement of decayed timber and replacement of
fittings
• Easing of doors and windows
• Cleaning of fire chimneys, gutters, etc
(B) SPECIAL REPAIRS
Def: The repairs that are done to overcome special problems as
soon as they occur are known as special repairs. These repairs
are very difficult and require more attention for their carrying
out.
Explaination:
Special repairs of the buildings include the following items of
maintenance works:
• Strengthening of foundations and foundations soil
• Rectifications of Leaking roofs
SPECIAL REPAIRS(-ctd-)
• Repair to damage concrete surfaces
• Repair to cracks in masonry walls
• Repairs at the window sills & joinery works at the
roof level of building
• Providing damp proof course in the existing building
• Repairs to the damp floors
• Anti termite treatment in the maintenance of
buildings
• Repairs to expansion joints