What is the most effective way to insulate a foundation wall minimally impacting the room’s aesthetics, considering closed cell foam and exterior access?
Asked by Prodan Šakić 
4 months ago
Last Updated: July 26, 2024
Do you have any ideas on how to insulate this foundation wall without taking up too much space in the room? I was thinking about using closed cell foam, but it would add an extra inch, plus whatever goes on top of it. I could also insulate from the outside, but I want it to still look good. Thanks for your help!
After insulating the exterior, have colored flashing bent to fit and tuck under the siding. Cut the top of the insulation at a 45-degree angle and match the flashing at a sheet metal shop. Choose a color that complements your decor. The sheet metal shop can provide materials in either 8 or 16-foot lengths. Collaborate with them to meet your needs. I’ve done this a few times and was pleased with the outcome.
Since it’s below ground level, there’s no need to insulate.
Is located above ground and experiences temperatures consistently below 20°f for 4-5 months each year
Attach drywall using PL Premium adhesive, then apply a thin layer of thin-set cement to secure metal corner bead for added durability.
Oh, mentioned that drywall typically only provides an R value of 0.5, which is definitely insufficient.
Hey, pointed out that it’s a knee wall located in a hallway of some sort. The heat loss through a concrete wall in that area would be minimal, almost negligible.
The original poster mentioned that the other side of that wall faces outdoors and experiences temperatures as low as 20 degrees Fahrenheit for several months each year. It appears to be an 8-inch thick concrete wall with an R value slightly above 1.1. There may be an air gap within the wall that could increase the R value, but the original poster feels that the area is chilly and wants to enhance the insulation.
Attach 3/4” foam insulation to the block using glue. Secure with tapcon screws every 2 feet at the top and bottom of the T111 panel. Create a 3 1/2” sill for the top and end. Round the front edge and add cove molding under the sill for a finished look. It won’t take up much space, but it will make a difference.
This product might be useful with an R value of 5.0. Your foundation will still be a bit cool, but it’s better than having nothing at all. You could also consider adding some interior insulation, but keep in mind that less than 1″ won’t make a big difference in insulation.
If you’re not interested in adding 4 inches, don’t worry about it. It might not make a huge difference in terms of insulation, but it will help seal the gap.