Insulating a portion of an uninsulated brick wall
user-982243
| Posted in Energy Efficiency and Durability on
Hi,
I live in a 1920s home in Montreal, Quebec Canada. The walls are un-insulated double brick. One wall faces out onto a covered porch, it has a large window in it and a hot-water radiator under it.
I am planning on constructing some built-in seating against this wall outside under the porch. I was wondering if it’s worth it to glue styrofoam insulation on the brick behind the seating? It will only be a section about 2′ high by 8′ long, right under the window and opposite the radiator on the inside.
Is it worth it, or will thermal bridging make this a futile effort?
Thanks as always for the help of the community!
Sean
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
In this article (https://www.greenbuildingadvisor.com/blogs/dept/musings/insulating-old-brick-buildings), Martin indicates the best option for insulation old brick walls is placing the insulation on the outside. You can use EPS and protect it with synthetic stucco. Insulating on the interior is much riskier.
Thanks for that link Steve. Yes, I would be insulating on the exterior. I was just wondering if it's worth going to the effort if it's for such a thin strip, (about 15% of the total surface area of the wall).
It will reduce heat loss through that part of the wall, which is not nothing. Especially if that's right where the radiator is. Whether it's worth it is debatable, but it seems like a perfectly reasonable thing to do, and it will reduce your energy use, although probably not enough to notice.
If you can find reclaimed EPS on Craigslist (maybe even as scrap), then that helps with the cost aspect.