Can we talk about figuring out the right insulation for an old house

I spent about two weeks trying to figure out the best way to add insulation to my 1920s house in Portland without causing moisture problems. I kept reading conflicting advice online about vapor barriers versus breathable materials. Finally, a local energy auditor suggested using dense pack cellulose in the walls, which was a game changer. Has anyone else found a good solution for older homes that balances warmth with preventing rot?

3 comments

3 Comments

daniel4741mo ago

Watched my neighbor's old house get moldy after they used the wrong insulation.

patriciah511mo ago

Mold from bad insulation like @daniel474 saw often starts inside walls before you see it. People forget that some old houses need to breathe, and sealing them up tight with modern foam can trap moisture. You end up with a perfect damp spot for mold to grow on the wood framing.

daniel4741mo ago

Actually the foam itself doesn't usually get moldy. It's the wood behind it that rots when moisture gets trapped. The foam just creates the problem spot.