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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

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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