exterior 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)

Suckingforce

Liftingforce

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 earthquake-proof, 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.

Window Framing Terms

Header– supports structure above

windows

Header Jack– supports header

Cripple Studs Double Plate Rough Sill Trimmer

– additional stud to trim out window

Double Plate

Cripple Studs

Header

Header

Jack

Cripple Studs

Rough Sill

Trimmer

PlatformFraming

Foundation

Sill (Mud Sill)

Floor Joist

Girder

Subfloor isPlatform

DoublePlate

Blocking

Sway Bracing

(cornerbracing)

Rafter or Truss

Also called

Western

Framing

Sheathing

Ledger

BalloonFraming

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

Beam and Posttypically 4’-8’ OC

beam

post

T&G planks2x6 or 2x8

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

building paper

wire fabric lath

furring nails

drip screed

sheathing vs. open frame

3 coats of plaster

brownfinish

scratch} 7/8”

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 Wall 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

Drawing Assignment Wall 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 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