Plywood, OSB or particle board sheathing is fixed using countersunk screws or nails to wooden or metal supports, driven just below the surface. The boards should fixed as shown in the drawing and:
- Have a 2-3mm gap between them.
- Be protected from the rain before the elzinc® trays are installed.
- Be supported at ≈600mm centres.
Sheathing board thickness is generally around 18 to 24mm, and the boards themselves are 1200 – 1250mm wide by 2400 – 2500mm long.
Plywood should be specified as structural plywood according to EN 636:2003, class 2. This is suitable for external protected applications.
Orientated strand board (OSB) should be specified as complying with EN 300:2006 OSB/3 load bearing boards for use in humid conditions
Particle boards should be specified as complying to EN 312:2010 class P5: load-bearing boards for use in humid conditions.