JECDIY

I think I've worked out it is a double-skinned Thermalite wall now. 👍

Hi all, I'm not sure I've come to the right forum for this but hopefully so! I am trying to find out if my house, built in 2002, would have had a double-skinned breeze block wall dividing the house and garage joining wall (not sure if building regulations mandated that in 2002). I am able to measure from said joining wall to the edge of a window on the inside, and then repeat on the outside. I've calculated the thickness of the joining wall is around 28cm. I seem to remember breeze blocks being quite thick but I note from my garage, where there are exposed breeze blocks, that they are in fact a lot thinner than I remember (either that or there are different varieties or they've become slimmer!). I think the exposed breeze block edge was 10cm so 28cm would comfortably fit double-skinned with an 8cm cavity. The reason I am asking is I remember reading an article on an older house, which had single brick and the owner was recommended to install insulation panels on the joining wall. I'm just wondering whether it is worth it or whether the cost of doing (even myself) would see a negligeable return with regard to heating bills (because I'm assuming it does have a cavity). Thanks in advance for any help!