Older walls, closed or open
Exterior Wall Insulation in Flint, MI
Filling empty walls in older houses through small holes, or spraying open walls during a remodel.
- Free on-site estimates
- Written quote listing foam type, thickness and R-value for each area
- Rim joists, attic bypasses and moisture checked before we price
Filling Walls That Were Built Empty
Exterior wall insulation matters in Flint because so many houses were built before walls were insulated. About a quarter of the city's homes date to 1939 or earlier, and many 1940s and 1950s houses got little more than a thin batt or nothing at all. On a cold January night those walls feel cold to the touch, and rooms on the windward side never quite warm up.
Closed walls: dense-pack and injection
In a finished house, the usual approach is to drill small holes from the outside (under siding) or the inside, fill each cavity with dense-packed cellulose or injection foam, then plug and patch. Before we do that we check for knob-and-tube wiring, blocking between studs, and signs of moisture. Balloon-framed houses also have open paths from the basement to the attic that should be sealed at the top and bottom.
Open walls: spray foam
When walls are open during a remodel or addition, spray foam fills the stud bays completely and seals the seams. Michigan's code table lists R-20, or R-13 plus R-5 continuous, for Zone 5 wood-frame walls. Closed-cell foam reaches the higher figure in a 2x4 wall where batts cannot.
Re-siding is a good time
If you are replacing siding, that is the cheapest moment to insulate walls from the outside. Old siding comes off, cavities get filled through the sheathing, and continuous foam board can go on before the new siding.
We will look at your walls and wiring and send a written plan. Get a free estimate
What Wall Work Includes
Options for the walls of Flint-area homes.
Dense-pack cellulose
Blown into closed walls at high density through small holes.
Injection foam
Foam made for closed cavities in existing walls.
Open-wall spray foam
Closed-cell or open-cell in stud bays during remodels and additions.
Top and bottom sealing
Closing balloon-frame paths at the basement and attic.
Published Wall Insulation Costs
| Job | Range and source |
|---|---|
| Spray foam, existing walls | $3.15 to $7.50 per sq ft (Fixr) |
| Spray foam, new construction | $2.75 to $6.50 per sq ft (Fixr) |
| All exterior walls, spray foam | $4,000 to $10,000 (HomeGuide) |
| Blown-in, exterior walls | $1,900 to $7,800, $1.10 to $3.70 per sq ft (HomeGuide); $2,000 to $4,000 (Fixr) |
| Dense-pack cellulose | $1.60 to $4.20 per sq ft (HomeGuide) |
| Open-cell / closed-cell | $1.50 to $3.50 / $3.00 to $5.00 per sq ft (HomeGuide) |
National ranges from Fixr (2025) and HomeGuide (2025-2026). Wall height, siding type, wiring checks and patching change the total. Our written estimate after the visit is the price.
How a Wall Job Runs
1. Check the walls
We look for wiring, blocking, moisture and existing insulation.
2. Written plan
Method, access side and price are written out.
3. Drill and fill
Each cavity is filled to density, then plugged.
4. Patch and clean
Holes are patched and the area cleaned up.
Exterior Wall Insulation Questions
Can you add insulation to walls without removing drywall or plaster?
Usually yes, by drilling small holes and blowing dense-pack cellulose or injecting foam. We check for wiring and blocking first.
Is spray foam or cellulose better for old walls?
For closed walls, dense-pack cellulose is the common choice; for open walls during a remodel, spray foam gives more R-value per inch and seals air.
Will insulating walls cause moisture problems?
Not when the outside is shedding water and indoor air leaks are sealed. We check for signs of leaks or rot before filling.
Do you need to remove siding?
Not always. We can work from inside or from under the siding, and re-siding projects make outside access easy.
Exterior Wall Insulation Service Areas
- Spray Foam Insulation in Flint, MI
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- Spray Foam Insulation in Grand Blanc, MI
- Spray Foam Insulation in Flint Township, MI
- Spray Foam Insulation in Fenton, MI
- Spray Foam Insulation in Flushing, MI
- Spray Foam Insulation in Davison, MI
- Spray Foam Insulation in Swartz Creek, MI
- Spray Foam Insulation in Mount Morris, MI
- Spray Foam Insulation in Clio, MI
- Spray Foam Insulation in Montrose, MI
- Spray Foam Insulation in Linden, MI
- Spray Foam Insulation in Lapeer, MI
Get an Exterior Wall Insulation Estimate
Ask about your walls. We will look and send a written plan and price.