For the last nine months or so I’ve been helping a friend who is trying to get her dream home built not far from the Greeny Flat. She started with a vacant lot and I’ve been consulting to her on the design, permitting, choosing a builder and attempting to ensure that the project gets completed to a high standard of energy efficiency. This is proving to be an interesting challenge and I’m discovering that builders here are generally not used to insulating and air-sealing homes very well. In fact, after twenty years of designing, building and testing homes in America, I’m finding that the ‘Standard Practices’ for Australian home builders leave a great deal to be desired in terms of energy efficiency.
To his credit, the builder on this project has been open to suggestions on how the air-sealing and insulation could be done better, but I’m finding that I have to watch things very closely or they just get done the way they have always been done. For example, as you can see in the photo above, I found that the insulation had been left out behind all of the electrical powerpoints and switches. When I asked the builder why, the answer was that ‘this is the way we always do it’. Apparently the electrician is concerned that, if there was a spark from an electrical connection, it could catch the insulation on fire. I pointed out that fibreglass insulation doesn’t burn but was told that it was a ‘code issue’.
So I sent emails to some code officials I know and asked whether there was anything written in the building code or Australian standards that requires you to not insulate behind electrical outlets. The answer was a resounding ‘No!’. in fact it is a legal requirement that the insulation be installed to the proper standard to meet BASIX in NSW. This means that the insulation has to be continuous without holes, gaps or folds. Unfortunately there is no requirement for building certifiers to inspect the insulation. It is up to the builder to sign an affidavit saying that the insulation was installed correctly, which is not very satisfactory if builders don’t know how it should be done properly.
All this makes me wonder how many homes in Australia are built with shoddy insulation. If you read the installation instructions for Knauf ‘Earthwool’ batts you’ll find the following; ‘Make sure all areas are insulated, behind electrical outlets, plumbing and services’. It also says, ‘When installing insulation between framing members, ensure that you achieve a snug fit avoiding any gaps, tucks and folds’. Clearly the builder on this project didn’t read those instructions (he has used some Knauf batts and some from another company) and simply followed ‘Standard Practices’ which clearly leave a lot to be desired as shown in the photo below.
The really sad thing is that this builder actually did a much better job of insulating than many I have seen. After spending some time pointing out the deficiencies in the job, he has assured me that they will be corrected before the gyprock goes up. I expect it won’t be perfect but it will be a lot better insulated and air-sealed than most Australian homes.
Another insulation issue that we ran into last week relates to the SIPS panels on the roof. Like the Greeny Flat, this project is roofed with Structural Insulated Panels (SIPS) which comprise a foam core clad with corrugated Colourbond on the top surface and smooth Colourbond steel on the underside. Unlike the Greeny Flat however, these panels (which are from a different company than ours) have gaps between the foam cores when they are installed. On the Greeny Flat, when the panels were snapped together the foam cores ended up tight against each other so that no air, heat or cold could move through the panel joints. On my friend’s project, as you can see from the photos below, even though these panels are snapped together as tightly as possible there is still a gap of almost 20mm between the foam cores and this was the same for all of the panels.
These gaps run all the way from the eave up to the ridge and constitute a major flaw in the insulation of the roof. In fact a quick calculation reveals that, added together, they total an area of at least one square meter that is completely uninsulated. The tricky thing is going to be figuring out how to insulate and air seal these gaps. We’re hoping that it will be possible to insert a hose into the gaps and fill them from top to bottom with spray foam but we’re yet to discover if anyone nearby has the equipment to do that or how much it might cost.
Sadly, if the builder had been more aware of good insulation and air-sealing practices, he could have quite easily solved the problem by inserting a strip of insulation into the gaps as the panels for snapped together. But clearly we have a long way to go before a high standard of energy efficiency becomes ‘Standard Practice’ in Australia. Meanwhile it seems like it would be a very good idea to have someone other than the builder inspect and certify that the insulation meets the requirements of the building codes and standards.