Plywood Installation Specifications for roofs / walls
Plywood is used as the substrate for:Euro Roof Profiles:
Doublestanding seam Angle seam Rollcap Rollseam Snaplock Nailstrip Metalshingle
Euro Wall Profiles :
Angle seam Vertical Angle seam horizontal Flatlock Lockseam Hookseam Rollseam Rollcap Custom Profile
The incorrect installation of the plywood substrate can affect the performance of the metal cladding.
A . Plywood to be ecoply (CD grade) plugged and sanded on the upper face B. Ecoply H 3.2 CCA treated (waterborne preservative with a green colour) grade F 11 / F 8 D. Ecoply 12.5mm is the minimum requirement, preference 15mm T & G, all edges have to be supported C. Sheet layout
- Place face grain at right angles to supports . - Sheet must be continuous over at least two spans (three framing members) - Lay the sheets in staggered pattern - with square edge sheets, allow a 3mm expansion gap between sheets
-
Vertical cavity batten setout for walls
400 c/c
- use blocking on the flat to provide gap where airflow is needed for ventilation - allow clearance for ventilation as required - for rafters at 900 mm centres it is recommended to use 75 x 50 mm purlins on the flat, at 600 mm centres . - all plywood edges have to be fully supported , with blocking or T&G - plywood should not overhang on the fascia line
D. Fixing of sheet
- The integrity of a plywood based roof system is directly related to how well the panel are fixed to the framing . - Screw fixings are preferred for all systems because of increased holding power and avoidance of head popping . - preferred screw fixing : stainless steel countersunk self drilling 10 g X 50 mm - spaced at 150 mm on edges and 200 mm on internal purlins - Fix at least 7mm or 3 fastener diameter from the sheet edges or behind tongues - Fix no more than 15mm from sheet edges - allow a 3 mm or 1 fastener diameter expansion gap between sheets - Do not over-drive gun nails or screws . - Fasteners should be corrosion resistant to a level appropriate to the end use,life expectancy (15or 50 years ) and expected exposure to moisture during construction and service .Galvanised fasteners are the minimum recommendation and are normally satisfactory in dry wood. Where ecoply or framing may become damp or is H 3 treated, use stainless steel screws for maximum durability . Follow the recommendations of the fastener manufacturer.
FAQ Manufacturers’ documents: Carter Hold Harvey Woodproducts ltd web: www.ecoply.co.nz ph : 0800 326 759
Documents NZBC E2 / AS! AS / NZS 1170.2 NZS 1170.5 AS/NZS 1604.3 AS/NZS 2269 NZS 3604 : 1999
External moisture Structural design actions - Wind actions Structural design actions-Earthquake actions-New Zealand Specification for preservative treatment-Plywood Plywood-structural-specifications Timber framed buildings