We are looking at using a membrane under the untreated bottom plate and wonder what type of membrane is to be used best? The ones on the market that we looked at are either 'embossed polythene dampcourse' or the 'bitumen damp-course'. Any comment to the above would be appreciated.
The ABCB Housing Provisions don't specifically deal with damp-courses under timber frames. The assumption is that they will be used in brickwork or under concrete slabs. However, it can be a useful precaution to place a damp-course under the outside wall of a timber frame that is seated on a concrete slab. While problems rarely arise if no damp-course is present, occasionally slabs are subject to edge dampness. At WoodSolutions we have no particular preference as to the type of damp-course to place under timber but suggest you seek one that complies with AS-2012-Waterproofing-membranes for external-above-ground use.
Can you please tell me maximum span for 190 x 45 mgp 12 H3 treated pine 600 mm spacing 40 kgs/square metre on roof rafters?
Supplement no. 5 to Australian Standard 1684.2-2010 for non-cyclonic areas tells us that in N1/N2 wind areas 190 x 45 MGP 12 rafters @ 600mm centres will span 5.3m. That's for a single span (supported only at each end).
Can you please confirm if the FZ eave detail on page 27 of the BAL rating guide is applicable for a tiled roof? And can the timber fascia be substituted for standard metal fascia?
WoodSolutions Technical Design Guide #04, Building with Timber in Bushfire-prone Areas, is currently under review. However, a 'generic' tiled roof system (ie. one not restricted to particular brand-name products) is included in Appendix H of Australian Standard 3959:2018. We will send you an extract from Appendix H under separate cover.
