Cinder block
Joseph1223
| Posted in Energy Efficiency and Durability on
I am looking for advice to insulate the exterior (Inside is finished) of an old home that has a cinder block basement. The home is 90 years old and the basement was put in some time after that (?). The home was bought 47 years ago. Please advise, thank you.
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Replies
I think you want to use EPS or XPS Rigid insulation, glued to the cinder block. I've been working on a different type of foundation insulation but remembered seeing the detail on page 24 of this guide:
https://www.homeinnovation.com/~/media/Files/Reports/Revised-Builders-Guide-to-Frost-Protected-Shallow-Foundations.pdf
I know exterior cinder block is often treated (painted) with some kind of tar-like substance, so I'd probably make sure it's OK to glue the Rigid insulation directly to the cinder block or whether you need to coat it with something first.
Your options are EPS or XPS foam, mineral wool or rigid fiberglass. The manufacturing process for XPS creates a lot of greenhouse gasses so it should never be used if you care about the environment. EPS is much better and performs similarly; it's just a little harder to get. Mineral wool allows water to drain, which is an advantage.
Concrete blocks are not very resistant to air or water, so it would be a good idea to consider applying a waterproof elastomeric membrane before installing the insulation. At minimum you should apply asphalt emulsion damp-proofing, but it is not as effective as elastomeric coatings.