Browse Forums Heating, Cooling & Insulation Re: Air tightness: one or two building wraps? 10Oct 03, 2022 3:10 pm We built in Sydney with a single exterior wrap. We haven’t moved in yet so I can’t comment whether it will deliver what was promised. I will say though that the PH consultant thought that A/C would provide enough dehumidification to move moisture through the wall. The builder disagreed and made us put in a ducted dehumidifier. So we have A/C, HRV and dehumidifier. The insulation is on the inside of the wall because the greater need for our place was cooling. I think we have about $35000 of mechanical climate management equipment if you add the 3 pieces of equipment. Re: Air tightness: one or two building wraps? 11Oct 03, 2022 3:55 pm ![]() who did you use for your WUFI analysis? we've been advised to get one done for our roof assembly as well as we're also seeking to adopt passivhaus principles with air tightness and building wraps. did you have to make any changes or interventions to your roof detailing as a result of the WUFI analysis? I rang a number of companies listed here: https://www.wufi.com.au/wufi-professionals/ At the time I made enquiries, most were very busy and unable to start until after a month or more. In the end I chose Building Physics RP because they were available to start within the week. I was happy with the work they did. Only thing to note was that they would have used climate data based on NCC climate zones, not the climate data that would be used for Passive House modelling, i.e. based on nearest climate station adjusted for elevation. No changes were required to my wall or roof details. I was confident that would be the case as I had already tested the wall and roof assemblies with Ubakus. If your assemblies require an internal wrap, you should also look at creating a services cavity between the wrap and the wall/ceiling linining (i.e. gyprock). This is to reduce penetrations from services (electrical, plumbing) or even from hanging pictures. I still am nowhere near starting the build. The builder I engaged to act as a consultant has lost interest in the project. Re: Air tightness: one or two building wraps? 12Jan 11, 2023 7:44 am Sorry to hijack thread: If you use both an external wrap and an internal wrap plus services cavity (as described in the first post), what will be the total thickness of your external walls? Exempt development if the house is existing. If it’s a new build it’s likely not an issue either but always call council to confirm. They’re usually very helpful. 3 4102 2 4483 2 23534 ![]() |