Plywood

Both decorative and structural Sheet product suitable for

• panelling• structural flooring• bracing• webs in composite beams

Standard size sheet• 2700 1200 mm• 2400 1200 mm• 1800 1200 mm Aboriginal Studies building,

Curtin University, Perth, WA

Photo: Geoff Boughton

Photo: Plywood Association Australia

Manufacture

Made by gluing and pressing thin laminates together to form a sheet

Grain in laminates in alternate directions - strength in two directions

Final plywood sheet

Seven laminates prior to gluing and pressing

face grain direction

grain in face laminate

Photo: Geoff Boughton

Uses

Panels (decorative, acoustic or bracing) Sheets - plate bending (flooring, formwork) Webs (I-beams, box beams)

Structural or appearance function for all of the above

Panels

Colour-matched ceiling panels

National wine Centre, Adelaide

Photo: Trevor Fox Australian Timber Design: 11

Extensive use of wall and ceiling panels with decorative and acoustic functions.

Chairs also feature plywood.

Sydney Opera House

Photo: Geoff Boughton

Decorative plywood with structural function

Handrails are structuralDecorative panels also have

bracing function

Exhibition buildings, Homebush, Sydney

Photos: Geoff BoughtonObservation deck, Sydney Showgrounds

Photos: Geoff Boughton

Sheets

Acts in minor axis bending in Flooring

• Can span in two directions• High strength material can be used for low

profile floors

Photo: Plywood Association Australia

Sheets

Formwork – requires:• Good surface finish• Water tight construction• Glues must be water resistant• Strength and stiffness to prevent

failure and sagging under wet concrete loads

Photo: Geoff Boughton

Photo: Geoff Boughton

Webs and gussets

High in-plane shear strength makes plywood ideal for webs and gussets in composite beams and portal frames

C-section purlin

Box section portal frame

Photo: Geoff BoughtonPhoto: Geoff Boughton

Plywood as wind bracing

Plywood gussets on Glulam portal

Plywood gussets on box beam portals

Salvation Army Church, Dural, NSW

Photo: Greg Nolan

Photo: Geoff Boughton Photo: Keith Crews

Veneer Quality

Veneer Quality A• High quality appearance grade• Suitable for clear finishing• Specified when surface appearance critical

Veneer Quality S• Appearance grade• Natural characteristics decorative feature

Veneer Quality B• Appearance grade suitable for high quality paint finish

Veneer Quality C• Non-appearance grade with solid (filled) surface• Suitable for flooring that will have decorative overlay

Veneer Quality D• Non-appearance grade with open imperfections• Suitable for structural plywood bracing

Sports stadium floor

Photo: Plywood Association Australia

Decorative Quality A

Service classes

Type A bond• For exterior plywood used in conditions of full exposure,• Interior plywood used in wet or damp conditions

eg around sinks, vanity units, laundry tubs. Type B bond

• Suitable for applications involving up to 2 years exposure to weather eg concrete formwork

• Used permanently in semi exposed applications eg exterior door skins

Type C & D bonds• Internal, dry conditions only• Non-structural

Properties of Plywood

Low variability in properties - reliable Usually graded as F-grade products

• (see Table 5.1 in AS1720.1 for plywood properties)

Specify:• Stress grade

• Thickness and number of plies

• Glues – interior, exterior, marine

• Quality of face finishes

• Species used on face and other plies