Basement insulation in Missoula MT - dry walls and a warmer floor upstairs
Cold floors upstairs and a chilly, drafty basement? We seal where the house meets the foundation, then insulate the walls with materials that stay dry.
How do you insulate a basement in Missoula without trapping moisture?
Basement insulation in Missoula covers your foundation walls, inside or out, so the heat you pay for stops slipping out through the concrete, and done right it leaves those walls dry instead of damp behind the insulation.
Most basement calls I get come from older houses where the floor over the basement stays cold all winter and the furnace never seems to catch up. The price moves with how much wall you've got, how easy it is to reach the spot where the house sits on the foundation, whether a finished wall has to come open, and which material the walls call for, since closed-cell foam runs more than foam board. The schedule mostly turns on what's in the way, like stored boxes, paneling or a damp corner that has to be sorted out before anything gets covered. Your written estimate lays out each of those steps and why it's there, so you see your own number before we start.
- Licensed and fully insured.
- Free in-person estimates.
- Replies within 1 business day.
Basement walls, rim joists and foam work
How we handle basement insulation
We start at the top of the foundation, where the wood sill plate sits on the concrete and the rim joist, the board that boxes in the ends of your floor joists, closes off the floor above, because that's where cold air sneaks in and there's no sense insulating a wall with a draft running over the top of it. It's the same habit I picked up framing, where you get the bottom plate right before you stand a wall. We seal that band with rigid foam cut to fit each bay and sealed at the edges, or with spray foam that air-seals and insulates in one pass. Then I pick what goes against the concrete, and it has to be something that won't hang onto dampness, so that's spray foam or foam board glued tight to the wall with no air gaps and every seam and edge sealed. Spray foam has to be covered with ignition-barrier paint or drywall, a fire-protective layer, so that covering gets planned into the job from my first visit.
On bare foundation walls I usually lean toward closed-cell foam insulation, because it controls moisture better than anything else you can put on the inside of a foundation, and to me that's worth the extra cost. Open-cell foam insulation can still work in a basement, but it takes a thicker coat to block vapor, so we talk through whether your walls and your space suit it before you decide.
Why Missoula homeowners call Summit Missoula Spray Foam Insulation for basements
I look at every basement myself
I come out to see each job in person, and I'm on the install with our crew instead of handing it off. The same person who found your damp corner is there watching how it gets sealed.
Framing background behind the foam
I framed houses for years, learned insulation working for an established installer and started our company in 2023. Knowing how a house goes together lets me tell you what's likely behind a finished basement wall before we open anything.
Licensed in Montana, fully insured
Montana requires construction contractors to be licensed with the state Department of Labor & Industry, and we're licensed and fully insured. It's a fair question to put to any crew you're comparing, because it covers your house while people are working in it.
Used to older Missoula basements
Most of our calls come from older houses in Missoula, Orchard Homes and the cities around them, inside and outside city limits, where the rooms stay cold and the heating bill keeps climbing. In those basements the rim usually needs sealing before any wall insulation does much good.
On a basement, the order is what counts, with the rim sealed before a single wall gets covered. When you're ready, call (406) 317-4027 or tell us about your basement.
Get a written plan for insulating your basement
Send the form and we'll get back to you within one business day to set a time for me to come look at your basement. The estimate is free and in person, with no obligation.
- Licensed and fully insured.
- Free in-person estimates.
- Replies within 1 business day.
What happens after you call about your basement?
Call or send a request
We get back to you and set a time for me to come out. It helps to jot down any damp spots you've noticed, what your walls are made of and any radon test results you have.
Walk the basement together
I go through the basement with you, look at the rim, the walls and any signs of moisture, and answer whatever you want to ask. Then I send a written estimate that explains each step, why it's there and what it costs.
Seal first, then insulate
Our crew takes care of anything that has to come first, seals the band where the house meets the foundation, then insulates the walls. Where we've used spray foam, the fire-protective covering goes on before we call it done.
Clean up and walk through
We clean up the basement and walk through the finished work with you. You'll see exactly what went where, so you know your own house a little better.
Basement insulation questions from Missoula
How much does basement insulation cost in Missoula?
Your cost comes down to the choices for your basement, and I'll put a written number on them after I've seen it. Foam board on the walls usually comes in lower than closed-cell spray foam, while opening a finished wall or adding the covering spray foam needs pushes it higher. The estimate shows each piece separately, so you can see what changes if you pick a different material.
How much heat does a basement lose?
Somewhere between 10% and 30% of a home's total heat loss goes out through the basement. In an older house with bare concrete walls, that's often where cold floors upstairs start. How much you'd save by insulating depends on the climate, what you pay for fuel, your heating system and how you live in the house.
Can I put fiberglass batts against my basement walls?
It's not a good idea, because fiberglass or cellulose placed against a basement wall can soak up a lot of moisture and stay damp. Putting a plastic vapor barrier over it makes things worse, since it traps that moisture in the wall. That's why we put foam against the concrete instead.
What is the best way to insulate a basement, inside or outside the foundation?
Insulation on the outside of the foundation controls moisture and saves energy, and in very cold climates it also protects the foundation from freeze-thaw cycles. It suits houses where termites aren't a problem, so check for them before choosing it. It also has to be protected from moisture while it goes in, so ask any crew how they'll keep it dry during installation.
Where can I get a radon test kit in Missoula?
Missoula County sells short-term radon test kits at a discount from 301 West Alder Street in Missoula, 406-258-4755, as the Montana DEQ lists it. The state's listing isn't dated, so call before you go. The state also says a test is the only way to know a home's radon level, whatever its age or foundation type.
How long does basement insulation take, and do we have to leave the house?
How long we're there comes down to the size of your basement, how easy the rim is to reach and whether a finished wall has to come open, so I'll give you a time once I've seen it. On spray foam days we'll tell you which parts of the house to stay out of and the re-entry time, when it's fine for kids and pets to come back, which comes from the foam maker's instructions.
Insulation work in nearby areas
Foam options that go with basement insulation
Closed-cell foam insulation
If your foundation walls ever feel damp, closed-cell foam is the dense, moisture-blocking option we usually put straight against the concrete and up in the rim joists.
Open-cell foam insulation
Open-cell foam is lighter and softer, and it can make sense in a dry basement or the walls upstairs when there's room for a thicker coat.