Insulating Behind Wall Panels

As part of our solar installation, we needed to get the asbestos removed from the work site. The main areas were our electrical switchboard and the eaves under the roof. We also had two asbestos panels beside the front door, and the company was willing to add those to the job for free. With the exception of the asbestos flue for our hot water system, this now means that the outside of our house is asbestos free.

We saw the removal of those asbestos wall panels as a great opportunity to check the insulation of our external walls, and there was no surprise at all that they were just empty cavities. Walls in this area should have a minimum R insulation value of 2.8 and, since this is a north facing wall, we wanted to go as high as we could.

Adding insulation to the wallThe highest insulation rating that we could find was R 7.0, and we had to get it as a special order, which only took a few days to arrive. We had the right amount of insulation to do the job, but we hit the first obvious hurdle – it didn’t fit. The batts were so thick that it took three adults to compress it inside. Unfortunately, when you start to compress this type of product, you also start to reduce the R rating.

After a quick strategy meeting, we agreed to carefully split the batts down the middle to make them half the thickness. This had the unfortunate effect of reducing their R rating, but it did mean that we could get them in the wall.

Given the price of this insulation, we would have been much better off measuring all of the internal dimensions before choosing a product, so I’m glad that we made this mistake with a smaller quantity instead of buying enough for the whole house. The surplus insulation has been put in the roof where it will be used to patch any gaps once we have a chance to get up there.

If you’re playing along at home…

…do you have any external panels like these that you could remove to add insulation to your external walls? Please share in the comments below if you have made similar modifications to your house and how it went for you.