Transcript 13 a-Ext walls (wood)

Exterior Walls (Wood)
Framing Techniques in Light Frame Construction
 General
Terms & Methodology
 Platform Framing
 Balloon Framing
 Post & Beam
Forces on Exterior Wall Construction
 Wall
had their own dead load
 Walls support vertical loads (LL + DL) from
– roof
– ceiling
– floors
 Must
also resist lateral forces due to
Wind--Horizontal/Lateral Load
 Wind
causes both
horizontal &
vertical movement
with vertical
forces called uplift
– Use of wind
speed map to
determine wind
speed (70 to 110
miles per hour)
Palm tree pierced by plywood missile, Hurricane Andrew
Wind Forces
 Horizontal
forces are
treated like seismic
 Vertical forces are
called uplift
– Wind blowing across the
structure creates a
negative pressure (sucking
force)
– Wind blowing thru an
opening increases inside
pressure (lifting force)
Sucking
force
Lifting
force
Earthquakes
 Shock
waves cause lateral and vertical motion
in a building
 Usual design, for vertical forces, will take care
of the vertical seismic forces
 Major factors effecting seismic forces:
– The type of structure (material its made of)
– Nature of soil under the building
 Building are not designed to be earthquakeproof, but to be earthquake resistant
Exposed Earthquake Module
Connections called “ductile” are designed to give the
building the ability to move, bend or stretch without
snap and breaking apart during earthquakes
Typical Wall Construction
 One
and two story framing
– 2” x 4” @ 16” O.C.
– Occasionally 2” x 6” @ 24” O.C.
 Three
story framing(load bearing walls)
– lower floor = 2” x 6” @ 16” O.C.
– other floors = 2” x 4” @ 16” O.C.
Double Plate
Window
Framing Terms
Cripple Studs
Header
 Header
– supports structure
above windows
 Header
Jack
Header
Jack
Rough Sill
– supports header
 Cripple
Studs
 Double Plate
 Rough Sill
 Trimmer
– additional stud to trim
out window
Cripple Studs
Trimmer
Platform
Framing
Rafter or Truss
Subfloor is
Platform
Also called
Western
Framing
Blocking
Double
Plate
Sway Bracing
(cornerbracing)
Girder
Ledger
Floor Joist
Sill (Mud Sill)
Sheathing
Foundation
Balloon
Framing
Studs extend
from sill to
roof line (full length)
Also called
Eastern Framing
Terms similar to
Platform Framing
Balloon Framing
 Used
primarily for 2 story construction
 Less chance of shrinkage or movement
– recommended for masonry veneer & stucco
 2nd
floor supported by wall with
– let-in 1x4 called a ribbon
 Less
overall material
 Longer members usually more costly
 Firestop blocking required
Balloon Framing
Terms
 Ribbon
 Firestop
Framing Construction at Corners
3
full studs
– good with
super
insulated
buildings
3
full studs
and
blocking
 3 full studs
and 1/2”
shim
Post &
Beam
Relatively new
and less
common in
residential
construction
Used in heavy
timber const
for years
T&G planks
2x6 or 2x8
beam
post
Beam and Post
typically 4’-8’ OC
Tongue & Groove Planking
 Used
for Roof or Floor when structure is space
24” or more O.C.
Shear Wall
Design
 Resistance
to lateral
forces resulting from
earthquakes or wind
 Connections:
–
–
–
–
–
1 sheathing to joist
2 joist to top wall
3 edge nailing
4 tie-down straps
5 anchor/shear
bolts
Detailing
areas of
Shear
Walls
Diaphragm transfer
Exterior Finishes
 Siding
– Wood Siding
– Metal Siding
» Steel
» Aluminum
– Vinyl Siding
 Stucco
 Exterior
Finish System--a nylon mesh &
plaster over insulation board
Wood
Siding
 Various
sizes
and Shapes
– Solid wood
– T1-11
(plywood)
» 4’x8’ sheets
– Masonnite
Lap board
» 8-12” x 16’
Steel & Vinyl Siding
 Higher
in Cost
 Lower in Maintenance
– no painting
 Long
lasting
 Concerns when using this siding
–
–
–
–
expansion
denting
cracking
rusting
Cement Stucco
Least expensive
sheathing vs. open frame
building paper
wire fabric lath
furring nails
drip screed
3 coats of plaster
finish
brown 7/8”
scratch
}
Interior Finishes
 Plaster
& Lath
 Wood Paneling
 Dry wall
Plaster & Lath
 Old
technique - not in common use today
– 3/8” - 1/2” thick lath
– 1/2” coat plaster
– uses a ground board at edges
Wood Paneling
 4’ x
8’ sheet panels
 vertical/horizontal/angle pieces
 solid boards
 wide range of wood types and colors
Drywall
 Commonly
called sheet rock, gypsum board
(GB), or plaster board
 typically 1/2” on wall, 5/8” on ceiling
 Nail directly to studs, nails commonly
8” OC
 Tape - 3 coats/ texture
 Green/blue board or cement board for
bathrooms
Assignment
 Sheet A-4
 Dimension
the enlarged entry plan
 Add restrooms to match A-1 & A-2
 Reference door and window (A-1 & A-2)
 Hatch or poche’ as needed
 Using elevation 1/A-4 create elevations for
A/A-4 and B/A-4
Drawing Assignment
Section
 5/8”dia
x 12”AB @ 32”
 8” Min from backfill to top FDN
 4” concrete slab w/ 6x6 10/10 wwf
or wwm (wire welded fabric or
mess)
 Blocking
 6-8”compact fill 95% density
 foundation wall 8” with normal
footing size (w x 2w) 30” frost
depth
 Foundation insulation
Wall
Drawing Assignment
Section Cont.
 2”x4”
wood studs
 Treated wood plate
 Found. (2) #5 bars top and bottom
and (1) #5 @ 18” o.c. vertical
 12”x18” cont. conc. footing w/ (2)
#4 bars x cont.
 #4 ties @ 18” o.c. (50% 2’-6” &
50% 1’-6”)
 T&G plywood subfloor (second
level)
Wall
Wall Section Drawing Cont.
 Slope
3:12
 5/8” GB inside wall
 Beam bearing @ 8’-0”
 Roof beam 3x10
 3/4” CDX plywood sheathing
 3/4” T1-11 siding (brick,
stucco, etc.)
 Overhang
18”
 2x2 starter board 1-1/2” from
edge