Wall insulation for existing homes
Twin Cities homes built before 1960 often have empty wall cavities or a couple inches of settled material. You can fix that without gutting the house.
Dense-pack retrofit
We drill access holes, blow cellulose or fiberglass into each cavity under pressure until it packs solid, then plug and patch. Access is either from the exterior (siding panels removed and reinstalled, or holes plugged and painted) or from inside. Dense-pack does two jobs at once: it insulates, and at proper density it substantially slows air movement through the wall.
Rim joist — the highest-value 4 hours in your basement
The rim joist is the band of framing at the top of the foundation wall, around the whole perimeter of the house. In most homes it is either bare or has a fiberglass batt stuffed against it doing almost nothing. It is typically the largest single air leak in a Minnesota house.
The fix is 2 inches of rigid foam cut to fit each bay, sealed at the edges with spray foam. It is a one-day job on most homes and homeowners consistently report the basement and first floor feeling different immediately.
What we do
- Dense-pack cellulose or fiberglass into existing wall cavities
- Rim joist rigid foam and sealing around the full perimeter
- Cantilever and bay window floors — the classic freezing-floor spot
- Knee walls and slopes in story-and-a-half homes
- Basement wall insulation — rigid foam with framing, done so it dries properly
- Crawlspace insulation and encapsulation
Planning ranges (Twin Cities, estimates)
| Work | Typical range |
|---|---|
| Dense-pack walls, average home | $3,500 – $9,000 |
| Rim joist foam and seal | $1,200 – $2,800 |
| Cantilever floor insulation | $600 – $1,800 |
| Basement wall, rigid foam and framing | $4,000 – $12,000 |
| Crawlspace encapsulation | $3,000 – $9,000 |
Estimates for planning; siding type and access drive the range.
One important warning
Do not insulate a wall you know is getting wet. Filling a cavity that has a leak turns a drying wall into a rotting wall. If there is water staining, failed flashing, or a known leak, that gets fixed first. We check before we fill.
What's included
- Free, no-pressure estimate
- Licensed & fully insured crew
- Cleanup included — we leave it spotless
- Same-day or scheduled service
- Written quote, fair pricing
- 24/7 emergency response
FAQ
Can walls be insulated without removing the siding?
Yes. We can drill from the interior and patch the drywall, or from the exterior by removing and reinstalling siding courses. Vinyl and steel siding come off and go back easily; stucco and brick are more involved.
How much will dense-pack save me?
Going from empty to dense-packed walls typically cuts 10% to 20% off heating costs, and the comfort difference on exterior-wall rooms is larger than the number suggests.
What is a rim joist and why does it matter?
It is the framing band at the top of the foundation, around the entire house perimeter. It is usually uninsulated and unsealed, making it the biggest single air leak in most Minnesota homes — and the cheapest to fix.
Will insulating my walls cause moisture problems?
Not when the wall is dry and the work is done correctly. It is a real risk on walls with an active leak, which is why we look for water damage before filling anything.
Wall Insulation & Rim Joist near you
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