Spray Foam Insulation in Duluth, MN

Spray foam is the material that fixes both problems at once, because it insulates and air seals in the same pass.

We are Duluth Spray Foam Co. We spray open cell and closed cell polyurethane foam in homes, cabins, shops, and pole barns across the Twin Ports.

Why insulation is a different problem in Duluth

Duluth runs roughly 9,700 heating degree days a year. The heating design temperature is somewhere around 15 to 20 below zero, which means your heating system is sized to hold 70 inside when it is that cold outside. That is a temperature difference of about 90 degrees, pushing on your walls and ceiling for months at a time.

Duluth is IECC Climate Zone 7. So is Superior, Hermantown, Proctor, and Two Harbors. Zone 7 is the coldest climate zone in the contiguous United States. The only colder designation, Zone 8, exists solely in interior Alaska. Insulation advice written for a national audience is usually written for Zone 4 or 5, and it does not transfer here.

Then there is the housing stock. A big share of Duluth’s homes were built before 1940, a lot of them on the hillside, many of them balloon framed. Balloon framing means the wall cavities run continuously from the basement sill all the way to the attic with nothing blocking them. Warm basement air rises up inside the walls and dumps into the attic. You can add all the blown insulation you want on top of that and the house will still be cold, because you insulated a chimney.

That is the actual work here. Stop the air first. Then add R-value.

Straight answers to the things people actually call about

Does spray foam fix ice dams?

Yes, when it is used to fix the heat loss that causes them.

An ice dam is a heat problem wearing a weather costume. Heat escapes the top of your house, warms the roof deck, melts the snow lying on it, and that meltwater runs down the roof. At the eave, past the exterior wall, there is no house underneath. That part of the roof is at outdoor temperature. The water refreezes there, builds a ridge of ice, and the next round of meltwater ponds behind it and works back up under the shingles.

The fix is to stop the heat from getting into the attic in the first place. In practice that means sealing every hole in the attic floor, which usually includes bath fans, recessed lights, wire and pipe penetrations, the attic hatch, the chimney chase, and the top plates of every interior wall. Then bringing the insulation up to depth and keeping the soffit vents open so cold outside air can wash the underside of the deck.

More detail on the attic insulation page.

What thickness of spray foam do I need in Minnesota?

It depends on the assembly, not on the house. The numbers most Duluth homeowners are looking for:

That last row is the one people get wrong. When you insulate a roof from underneath and there is no vent channel above the insulation, the code requires a minimum amount of air impermeable insulation in direct contact with the sheathing before you add anything else. In Climate Zone 7 that minimum is R-30, which is about five inches of closed cell. Less than that and the sheathing runs cold enough for interior moisture to condense on it.

We go through the whole thickness question on the closed cell page.

How much does this cost?

Spray foam is sold by the board foot. One board foot is one square foot sprayed one inch thick. In this market:

• Open cell: roughly $0.45 to $0.75 per board foot installed
• Closed cell: roughly $1.00 to $1.75 per board foot installed

By job, with the caveat that every one of these depends on access, prep, and what has to come out first:

Those are ranges so you can budget, not quotes. Nobody can price a spray foam job accurately without seeing it, and anyone who gives you a firm number over the phone without asking about access is guessing.

More on what moves the number on each service page.

Should I do the crawl space or the attic first?

Attic first, in almost every case. Heat rises, the temperature difference at the top of the house is the largest in the building, and the attic is usually the cheapest square footage to treat. It is also the job that stops ice dams.

The exception is when the crawl space is actively causing damage. Standing water, a rotting subfloor, frozen supply lines, or mold on the joists is a repair, and repairs come before efficiency. A persistent musty smell upstairs belongs on that list too, because that is crawl space air getting into your living space. If your crawl space is wet or you can smell it, deal with the crawl space.

Full reasoning on the crawl space page.

How we work

1. You call (218) 514-6594 or send the form. Tell us what the house is doing, not what product you think you need. Cold floors, high bills, ice at the eaves, a bedroom that never warms up. The symptom tells us more than the guess.
2. We look at it. Attic, basement, crawl space, and the mechanicals. It is hard to size an insulation job from a driveway.
3. You get a written scope and a real number. What gets sealed, what gets sprayed, at what thickness, what R-value that lands at, and what it costs. If part of the job is better done with blown insulation than with foam, that is in there too.
4. We spray it. Most residential jobs are one or two days. You will need to be out of the house during the spray and for a period afterward while it cures and the space ventilates. Typically that is 24 hours, and the exact number comes off the product data sheet.