Frequently Asked Questions
Spray Foam Insulation Questions
How much should I expect to pay for spray foam insulation?
HomeGuide's 2026 figures put installed spray foam at $1.50 to $5.00 per square foot, rim joists at about $2,000 to $2,500 and a whole house at $8,000 to $20,000. Your written estimate after the visit is the price.
Which type of spray foam has the highest R-value?
Closed-cell, at about R-5 to R-7 per inch in HomeGuide's guide, compared with R-3.5 to R-3.7 for open-cell. It also slows vapor, which is why we use it on rim joists, basements and steel.
What is spray foam insulation?
It is a two-part liquid that is sprayed on, expands and cures into a solid foam. It insulates and stops air in one step, which loose insulation cannot do.
Why are people removing spray foam insulation?
Usually because it was put in wrong: too thick, over a leak or mixed badly. HomeGuide puts foam removal at $1.00 to $2.50 per square foot, so planning it right matters.
What R-value should an Allegan attic have?
Michigan's code table lists R-38 for ceilings in Zone 5. The DOE recommends R-60 for an existing attic with little insulation, or adding R-49 over 3 to 4 inches.
Can you insulate an old house without opening the walls?
Usually. Dense-packed cellulose goes into closed walls through small holes after we check for knob-and-tube wiring and blocking.
Spray Foam Insulation Questions
Can spray foam go on a fieldstone foundation?
Yes, closed-cell bonds to stone and fills the many gaps, as long as the wall is not actively wet.
Is spray foam good for a lakeshore cottage?
Often, especially on floors over crawl spaces and on rim joists, where it makes the cottage usable in cold months.
Do I need to leave the house during spraying?
Yes. HomeGuide recommends staying out at least 24 hours.
Will foam hide problems in an old house?
It can, which is why we check wiring, leaks and rot first.
Attic Insulation Questions
Will attic insulation stop ice dams?
Air sealing plus insulation and clear eave vents are the main fixes.
Can you insulate an attic with knob-and-tube wiring?
Not over live knob-and-tube. An electrician should check or replace it first.
Can new insulation go over old?
Usually, if the old is dry and clean and the ceiling is sealed.
How long does an attic job take?
Most take one day.
Old-House Wall Insulation Questions
Will dense-pack settle?
Not when installed at proper density.
Can you insulate under old siding?
Yes, often by lifting siding and drilling through the sheathing.
What about knob-and-tube?
It must be checked or replaced before walls are filled.
Does it help with noise?
Yes, filled walls also cut outside noise.
Rim Joist, Basement & Crawl Space Insulation Questions
Is rim joist foam worth it?
In most older Michigan houses, yes. It seals one of the leakiest spots in the house.
Can you foam a damp fieldstone wall?
Only after the water source is handled.
Should I insulate my cottage floor or crawl space walls?
If the cottage is heated year-round, the walls; if it is closed for winter, often the floor.
Does exposed foam need covering?
Often a thermal or ignition barrier is required; we include it in the plan.
Pole Barn & Farm Building Insulation Questions
Will foam stop my barn from sweating?
Yes. Closed-cell foam keeps moist air off the cold steel.
Can you foam a livestock barn?
Yes, with attention to thickness, coatings and ventilation.
Is there a permit for barn insulation?
Agricultural buildings are often treated differently; check with your township.
Can you work in winter?
Yes, with the space warmed so foam cures properly.
Insulation Removal Questions
How do I know insulation should come out?
If it is wet, moldy, smells or shows droppings.
Can you remove vermiculite?
Only after testing; positive material needs a licensed abatement contractor.
How long does removal take?
Most attics take a day.
Can you clean out a cottage crawl space?
Yes, and then insulate it properly.