Browse Forums Building A New House Re: New house build - Passive House 10Jun 21, 2023 4:53 am Architectural Homes & Duplexes - specialising in custom designing homes to your budget Get a Free Onsite Consultation Today or send a PM for information, questions or advice. Re: New house build - Passive House 17Jun 22, 2023 11:36 pm alexp79 Also, what is the plan with regards to the walls insulation? These studs seem to be standard 90 mm ones so certainly won't be able to fit a lot of insulation. Hebel surely adds a little to the external R values over brick, but I don't really see how you are planning to fight thermal bridging of the framing. It is possible to satisfy Passive House requirements in Sydney with standard 90mm studs and R2.5 insulation. I had a design modelled for Passive House with this wall assembly and it passed. As Sydney has a mild climate, especially on the coast, Passive House is relatively easy to achieve compared to other locations and does not have to be overkill. Similarly, 90mm timber studs can pass the thermal bridging requirements for Passive House, at least in Sydney and other locations with mild climates. If there is any doubt, it needs to be modelled. Attention must be paid to frame corners to ensure there is enough insulation and they are not simply packed out with more timber or have voids. Bricks and Hebel blocks/panels typically do not contribute to the wall insulation value for Passive House modelling. External cladding is considered to be outside the thermal envelope of the building if there is a ventilated cavity between the wall and the cladding. Re: New house build - Passive House 18Jun 22, 2023 11:50 pm Oh, thanks, good to know. I have also noticed you do not have any slab edges insulation. Is it also fitting the model? It looks like the main thing for you will be with achieving the right degree of airtightness? But, at the same time, if you are planning to use standard breathable insulation and gyprock, then you should be taking into account additional air exchanges due to higher degree of vapour permeability? But then this OSB you have outside your frame is much less permeable than your insulation and, therefore, will be very well preventing the water vapour from escaping. During colder winter nights and sometime days it will accumulate and condensate and therefore your receive the moisture inside your insulation and framing. Therefore, you should be heavily relying on mechanical humidity regulation (HRV won't be good enough, you would likely require full scale ERV system) as otherwise the mould and rotting will be almost guaranteed in the long run. Unless you plan to install a vapour barrier, but in this case it can be easily punctured during the plasterboard installation. They have this problem in the UK where a lot of houses are using OSB boards in front of insulation and get serious structural damage to their framing in just 15-20 years (due to rotting) and in some cases severe health issues for the residents (due to mould). Re: New house build - Passive House 19Jun 23, 2023 8:09 am Ventilated wall cavity? I'm assuming the house would have gone through wufi modelling. I would still ask the question, see if you can get your builder to do it 3 1678 Thank you so much everyone. This all makes a lot of sense. I guess when you talk to a builder who butters up everything to look very polished, you get to start believing… 7 24870 6 60443 |