Transcript Conventional Construction

Let’s talk about Conventional / Traditional Construction…
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Conventional / Traditional Construction
Bricks and mortar is a phrase that readily springs to mind when it comes to house building and with it connotations of a solid, secure structure. From the wooden building blocks and Lego
of childhood to talk of 'investing in bricks and mortar', or 'the building blocks of life', there's
something very safe and familiar about bricks.
A masonry build is something that lasts, too - you only have to walk down a street in any city
to see that. In fact, brick-and-block construction is the cornerstone of the self-build market,
with around 70 per cent of self-builders opting for this method.
You only have to look at the Egyptian pyramids or Greek temples still standing to realize the
permanence and enduring beauty of masonry construction. Building with concrete is not new—
this construction method has been used for residential construction throughout the world, for
centuries because of its strength and durability.
Traditional masonry construction refers to houses built in block and brick. Although brick is
used countrywide as an outer skin or 'facing material', it is often substituted with local quarried
stone or a reconstituted replica.
Despite the use of the term 'traditional', masonry construction has incorporated many modern
developments and has come a long way since the days of solid stone walls. Improvements in
technical design, materials and accessory products have enhanced the performance of these
structures significantly in terms of structural integrity, thermal efficiency and moisture
protection. Progress has led to developments such as thin joint systems with Aircrete blocks.
"Concrete masonry construction offers many advantages in terms of termite resistance, thermal
mass, sound attenuation, and fire resistance."
The Conventional Construction Process
Following excavation and installation of foundations, bricklayers erect cavity walls that consist
of an inner and outer skin.
The inner skin is the main structural element, which supports internal floors and the roof
structure. It is constructed using concrete blocks laid on beds of sand and cement mortar.
The outer skin is the first line of protection against the elements and provides the aesthetic
element to the structure. It is constructed using brick, stone or block work, which can take a
number of finishes. The two skins are connected by steel wall ties and separated by a cavity
that is partially or fully filled with insulation.
The Conventional Construction Process Contd…
Internal floors can be constructed using timber joists, composite timber I
beams, or one of the precast concrete systems available. The roof is usually
traditional cut timber or prefabricated truss construction.
Once the roof is completed and the windows and doors are fitted, the building
is watertight the internal trades can get underway. The internal face of the
block work can take a range of finishes including 'dot and dab' plasterboard and
wet plaster.
Various details are required around openings and other parts of the structure in
order to maintain structural integrity and to prevent water penetration and heat
loss.
We'll have a look at masonry construction and the advantages and
disadvantages of choosing it as the method of construction for your dwelling.
What is brick-and-block in Conventional Construction
Brick-and-block involves working entirely on site - unlike build techniques such as timberframe. The build starts with concrete foundations and finishes with the roof. Walls consist of a
block-built inner skin, a cavity, and a brick-built outer skin. The two skins are held together
with wall ties to add strength, while the cavity is filled with insulation. Internal load-bearing
walls are built in block. All walls are built to first-floor level at which point timber floor joists
or pre-cast concrete floors are added before the build is completed to roof height. Once,
watertight, internal block walls are finished using board or wet plaster.
Conventional Construction – Advantages
•It is a flexible system in both design and construction.
•Depending on your house design and the materials specified, masonry construction can be one of
the most cost effective of all the build methods.
•As the most common form of house construction, there are plenty of tradesmen and specialist
knowledge available to complete your project.
•A proven track record means it is accepted and understood from designers and builders to lenders,
insurers & warranty providers.
•Materials are readily available from local builders merchants.
•Materials are often manufactured and sourced locally (Traditional Housing Bureau).
•Easy to modify or extend.
•Good levels of sound insulation are achieved, which can be improved by using precast concrete
floors.
•Masonry provides good fire protection.
•Masonry materials are strong, durable and long lasting, spreading their impact (Traditional
Housing Bureau).
Conventional Construction – Advantages Contd…
• Good thermal performance. Masonry materials have a high thermal mass,
which is their ability to absorb and store heat. In the summer this keeps the
building cool and in the winter the heat stored during the day is slowly released
back into the house at night leading to a more constant, comfortable
environment. This effect is improved if plaster is applied directly to blockwork
in lieu of dot and dab plasterboard.
• When the building has reached the end of its useful lifespan, bricks and
blocks are 100% recyclable (Traditional Housing Bureau).
• Resistance to hurricanes, tornadoes and other weather-related phenomena
since the entire structure is tied together from the footings to the roof assembly
with steel reinforcement, achieving a a natural strength of 400 pounds per
running foot compared to just 80 pounds for wood framing
Conventional Construction Disadvantages
• On-site construction means that progress and your program of work can be
affected by adverse weather conditions.
• Materials need to be stored on site and protected from the weather before they are
incorporated into the building structure.
• New work needs to be protected from the elements.
• On site construction is labour intensive.
Quality Issues in Conventional Methods & Materials
Conventional designs that compromise beams, columns, brick/block infills & plastering have
inherent inefficiencies during construction. Brick/block wall infills are labour- intensive &
cement-sand plastering, a wet process, is often messy & requires more preparatory work. There
are also constraints in concealing & routing M&E services. Apart from using more intensive
manpower & longer construction duration, there are some inherent difficulties in achieving
high quality. Please find given below, information on the challenges posed by such
conventional design & materials.
Consequences in choice if internal finishes - Choice of methods & material affect
workmanship quality
Traditional formwork system: More joints & poor surface finish
Traditional formwork system has more connections & joints & it requires more manpower to
erect, maintain & dismantle. During erection, close monitoring & supervision is needed to achieve
the desired workmanship quality of the finished concrete. If the formwork is not erected properly,
the end product would not be satisfactory. Often this means another layer of thick plaster is
required to cover the uneven concrete surface.
Traditional formwork system: More housekeeping.
Poor concrete surfaces: Thicker plaster is required
Restricted M & E services run
Many services in a building e.g. electrical, ACMV & sanitary plumbing, etc are concealed
under slabs or covered by false ceiling. If there are too many beams, especially non-shallow
beams, it may be difficult to locate such services under floor slabs. This may restrict the height
of false ceilings or the floor storey height may need to be increased to accommodate such
services.
More columns & beams: Limit M&E services run
Internal beams restrict height of false ceiling
More turns & corners
The width of RC column may be different from the width of the brick wall laid against it,
especially in internal partitions, e.g. a 200mm wide column & 100mm thick brick wall. In
such situations, an offset of 100mm will appear wherever an RC column adjoins brickwork
resulting in a non-flush surface with many corners & returns. There will be greater
difficulty in completing the architectural finishing works like plastering, skirting,
architraves, etc.
The offset of RC & brickwork creates more turns & corners
More precise work required for turns & corners
Additional treatment to joint between two different materials
At the joint interface between different materials e.g. RC & brickwork, special treatment like metal
lathing is required to ensure there is proper bond and to prevent cracking of plaster wall at the
joint. The additional number of joints increase the time and cost of construction.
Providing metal lath on each
RC & brick joint
Consequences in choice of external finishes
Brick and RC Joints need additional treatment
Scaffolding: More housekeeping & longer construction period
Thick plaster: Possible waviness
Bulged RC surface requires thick plaster
Common issues in conventional methods
Scaffolding tieback holes
To carry out plastering, scaffolding is necessary. The tie back holes used for securing scaffolding
can be patched and re-painted only after the scaffold is dismantled. This is to be carried out via
gondolas. Due to the different stages of operation, patchiness or uneven finishing on the surface is
inevitable on the external wall surfaces.
Scaffolding tie-back holes on façade plastering
Possible cracks & hollow plastering
Depending on the background substrate, plastering operations are usually 2 or 3 coats work &
may compromise a spatter-dash, base or scratch coat & final skim-coat. Proper curing is also
required between coats. This affects the overall progress. Besides, if the plaster thickness
exceeds the allowable thickness, there is possibility of defects like cracks & hollowness
appearing on the surface due to shrinkage of mortar.
Surface cracks & hollowness appear when plaster is too thick
Additional waterproofing treatment on joints
For external surface at RC & brick joints, besides laying metal lath, a layer of waterproofing
treatment is required to ensure water tightness. Failure to execute these measures properly may
result in defects such as cracks & seepages. All these measures are needed to ensure quality in
construction & will add to construction time & cost.
External joints require waterproofing treatment
Potential water seepage if joints are not treated properly
Housekeeping & longer construction period
Scaffolding & wet trades like brickwork & plastering evidently require more housekeeping
effort. More time is required to erect & dismantle scaffolding. This may hinder other
concurrent activities & lead to longer construction period.
More housekeeping is required for scaffolding & wet trades.
Although adopting conventional methods and materials may lead to
lower construction costs in some cases, the majority of wet trades
pose inherent difficulties in achieving quality construction compared
to buildable dry construction. In its place, good buildable design
systems that facilitate ease of construction, depend less on-site
labour, improve productivity & quality should be considered.
Conventional Eco-Friendly Material
•Bamboo, Bamboo Based Particle Board & Ply Board, Bamboo Matting.
•Bricks Sun dried.
•Precast cement concrete blocks, lintels, slab. Structural & non-structural modular elements.
•Calcined Phospho Gypsum Wall Panels
•Calcium silicate boards & tiles.
•Cellular Light Weight Concrete Blocks.
•Cement Paint
•Clay roofing tiles
•Water, polyurethane & acrylic based chemical admixtures for corrosion removal, rust prevention, water
proofing
•Epoxy Resin System, Flooring, sealants, adhesives & admixtures
•Ferro-cement boards for door & window shutters
•Ferro-cement Roofing Channels
•Fly-ash Sand Lime Bricks & Paver Blocks
•Gypsum Board, Tiles, Plaster Blocks, Gypsum plaster fibre, jute / sisal & glass fibre composites
•Laminated Wood Plastic Components
•Marble Concrete Roofing Tiles
•MDF Boards & Mouldings
•Micro Concrete Roofing Tiles
•Partical Boards
•Polymerised water proof compound
•Portland Pozzolana Cement Flyash / Calcined Clay Based
•Portland Slag Cement
•RCC Door Frames
•Ready Mix Cement Concrete
•Rubber Wood Finger Joint Board
•Stone Dust
•Water proof compound, adhesive, Polymer Powder.
How is it beneficial?
The environment friendly building materials are composed of renewable, rather than non-renewable resources.
These materials are environmentally viable as their impacts are considered over the life of the material. Use of these
materials provides the following benefits.
1.
Resource Efficiency - benefits like high recycled content, naturally available, efficient manufacturing processes,
locally available, high salvage potential, reusable and highly durable.
2. Indoor Air Quality - Selection of the materials with benefits like low/ non-toxic, minimum emissions, low VOC
content, moisture resistant and healthfully maintained.
3. Energy Efficiency - Selection of the materials with benefits like reduction in energy consumption in buildings and
facilities etc. Further elaborated in Energy related EBGH.
4. Water conservation - Selection of materials with benefits like reduction in water use in buildings and conserve
water in landscape areas. Further elaborated in Water related EBGH.
5. Affordability - Is considered to compare the eco-friendly building materials to conventional materials within a
defined percentage of the overall budget of the building.
Apart from the above benefits, using these materials have the following advantages
Have similar or low price compared to conventional building materials when total life cycle cost is assessed
Do not exhaust the existing supplies of finite materials
Save energy and reduce harmful emissions
Helps in reducing environmental degradation
Encouraged by building promotion council, so planning/ building permissions are easy to get
Since they are less harmful to occupants, they make healthier and safer buildings
Sustainable material options for conventional Building Materials
Sr.N Conventional
o
Material
01
Cement /
Concrete
02
Metals
03
Masonry Units
Sustainable Alternative Material
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04
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Mortar & plasters 
05
Wood
06
Plastics
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Fly ash lightweight aerated concrete blocks
Pre-cast hollow concrete blocks
Pre-cast concrete blocks
Precise aerated cellular concrete walling blocks & roofing slabs
Steel with verified recycled content
Aluminum with verified recycled content
Scrap / salvaged steel & aluminum sections
Antique iron & brass fixtures
Fly ash lime gypsum products (bricks, aerated concrete blocks, stabilized
mud blocks)
Pre-cast materials (stone blocks, concrete blocks, hollow concrete blocks,
cellular concrete units)
Stabilized compressed earth blocks
Lime, pozzolanic materials, rice husk ash to replace part of cement inn
cement based mortars
Fly ash (replacing 25% of cement)
Medium density fiber boards
Particle boards
Rice husk boards
Cement bounded composite panels
Recycled plastic panels
Sustainable material options for conventional Building Materials Contd…
07
Glass
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Recycled content glass (fiber glass, glass wool)
High performance glazing
08
Finishes (Walls & ceilings)
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Gypsum plaster boards
Ceramic tiles
09
Finishes (Flooring)
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Terrazzo (crushed stone, glass, flinters, etc)
10
Finishes (Paints)
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Water based paints & acrylics (Low VOC)
11
Finishes (Sealants & adhesives) 
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12
Finishes (Furnishings)
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13
Doors & Windows
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Sealants: Acrylics / Silicones / Siliconized acrylics
Adhesives: Acrylics / phenol resins
Recycled content materials (steel, glass, solid wood)
Powder coated finishes for metals
Water based finishes like EOC varnishes for wooden
components
Natural fiber reinforced polymer composite panels
UPVC / PVC panels
Advantages of Sustainable building materials used in various construction phases
Sr.No Alternative Material
Structural Materials
01
Pozzolanic materials
02
Flyash for concrete & mortar
03
Ferro cement & precast
components
04
Precast RCC & Ferro cement
frames
05
Recycled steel sections
06
Ready Mix concrete
Advantages
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Upto 35% of flyash can directly be substituted for cement as blending material
Saves energy upto 20%
Superior microstructure leading to lower permeability
Higher electrical resistance leading to lesser chances of reinforcement corrosion
Substitutes stone chips in concrete reducing dead weight
Promotes fuel efficiency & carbon in ash provides sufficient heat
Possess 28-day comprehensive strengths of the order of 40 MN/m2 & densities 1100 to
1800 kg/m3
Better thermal & acoustic insulation & high fire resistance
Are 85% recyclable & energy efficient
No plastering required on inner side & no curing required
Saves reinforcement & stronger than cast-in-citu structures
High fire resistance & better insulation
Are 1/3rd in cost compared to 2nd grade timber
Higher strength to weight ration than RCC
20% saving on material cost
Suitable for precasting, flexible in cutting, drilling & jointing
Can be made entirely of recycled scrap iron
High strength & non combustible
Available forms permit efficient & uniform application
Resistant to weathering, erosion & termite infestation
Water reducer & workability enhancer
High strength, resistance to thermal cracking & durable
Quantities & ratios of mix managed better
Little wastage & less man power required
Advantages of Sustainable building materials used in various construction phases
Contd…
Sr.N Alternative Material
o
Bricks & Blocks
01
Flyash sand-lime bricks / blocks
02
03
04
05
06
Advantages
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Flyash lime gypsum bricks
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Aerated light weight concrete
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blocks
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Flyash cellular lightweight concrete 
blocks
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Stabilized compressed earth blocks 
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Building blocks from mine &
industrial waste
Available in several load bearing grades
Saves in mortar plastering
Low water absorption, only sprinkling of water sufficient
20-30% less thermal conductivity than concrete blocks
High compressive strength than clay bricks
Give highest strength among various bricks
Most suitable for mechanized operations
Fine finish & energy efficient
Lower requirement of mortar in construction
Reduces dead loads on super structure
Raw material contains 70% recycled power plant waste
Good thermal insulation (upto 26% power savings)
Requires very less water in construction
Manufacturing process is 100% recyclable
Substitutes stone chips in concrete, reduces dead weight
Has a density of app. 1/5th of concrete
Are substitutes for conventional bricks & concrete blocks with
densities from 800 kg/m3 to 1800 kg/m3
Utilizes waste from mining (iron ore) industries
Reduces air, water & land pollution
Is energy efficient & cost effective
Highly suitable for speedy & mortar less construction
Can be used for all application of burnt clay bricks
Advantages of Sustainable building materials used in various construction phases
Contd…
Sr.N Alternative Material
o
Plasters
01
Fibre reinforced clay
plaster
Advantages
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02
Phospho gypsum plaster 
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03
Calcium silicate plaster 
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Roofing
01
Micro concrete roofing 
tiles
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02
03
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Clay tiles
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Bamboo matt corrugated 
sheets
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Reduce plastic shrinkage & permeability
Plant fibres act as reinforcement & controls cracking
Provide increased impact & abrasion resistance
Waste utilization prevents water & soil pollution
Is energy efficient & cost effective
Has a very high setting time & comprehensive strength
Are economic, produces less waste
Smart finish & less energy consuming
Non-emission of VOC & other toxic fumes
No skilled manpower required, durable & less water consumption
Highly cost effective, durable & lighter than other tiles
Validated & certified by BMTPC (Building Materials & Technology
Promotion council0
Easily installed, colored to interest & reduce heat gain
Uniform in size & more durable
Cost effective, fire resistant & energy efficient
Low self weight, reduces loading on super structure
Resistant to water, fire, decay, termites etc
Light, possess high resilience & better thermal comfort
Bearing strength comparable with GI sheet, ACCS etc.
Advantages of Sustainable building materials used in various construction phases
Contd…
Sr.No
Alternative Material
Flooring
01
Terrazzo / Marble mosaic flooring
Advantages
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Made using waste & recycled material
Forms a good waterproofing layer on exposed surfaces
Is very cost effective
02
Phospho gypsum tiles
03
Bamboo board flooring
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Manufactured from waste gypsum
Light, fire resistant & good acoustic effects
Good alternative to wooden flooring
Is tough, easy to install & water resistant
Cost effective
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Use of waste / recyclable timber
Can be reused by converting into chips / particles for particle boards
Wood Substitutes
01
Salvaged wood
02
Recycled laminated boards
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Use of recycled waste (toothpaste containers)
Sound proof, termite resistant & expansion resistant
03
Bamboo matt boards & veneer composites
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Economical compared to bamboo matt board for thickness more than 6mm
Higher strength than veneer plywood
Superior physical, mechanical properties compared to bamboo matt board
04
Fibre reinforced polymer boards
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Made from plastic components, low installed & maintenance costs
Light in weight, high strength
Good resistance to weathering & fire
05
Flyash jute polymer composites
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Cost effective as compared to conventional materials
Stronger, more durable & resistant to corrosion
Developed using Flyash as filler & jute cloth as reinforcement
Advantages of Sustainable building materials used in various construction phases Contd…
Sr.No Alternative Material
Boards & Panels
01
Calcinated Phospho gypsum wall
panels
02
Fibre Flyash cement boards
03
Gypsum Plaster boards
04
Composite door shutters
Paints
01
Cement Paints
02
Water based compounds
Sealants & Adhesives
01
Waste based compounds
02
Epoxy resins
Advantages
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Durable, cost effective, water & pest resistant
Smooth, easy installation & no need of plastering
Ability to take add-on’s like wall paper, decorative laminates, painting etc…
Take paint directly, is fire resistant & easy laying of electrical conduits
Made of recyclable materials like Flyash, agro waste etc
Are stronger & more cost effective
Used for roofing, partitions & panels
Light weight, fire resistant & good thermal & sound properties
Used as lightweight partition panels, false ceiling lining, decoration paneling, boxing, cladding etc…
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Low water absorption value (6-7%)
Density nearly 50% of timber shutters
Easy installation & maintenance
Can be painted, polished or laminated
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Has very low VOC (Volatile Organic Compounds)
Easy to apply & highly economic
Has good water resistant properties
Has good covering capacity, easy mixing character, better resistance to crazing & microbial growth
Have same performance and durability as conventional solvent based paints
Has very low VOC
Have no cost variations compared to conventional ones
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Has very low VOC
Have no cost variations compared to conventional ones
Have same performance and durability as conventional solvent based paints
Are eco-friendly, consume lower energies during their life cycles
Easily disposable or recyclable
Lower occupational hazards & emission levels
Initial cost high but justified by overall life cycle performance