Is $8,400 to spray 4" closed cell foam on roofline a fair price?
Project Details
My wood frame house was built in the late 1800s. The upstairs furnace is located in the attic. Currently, there is only about 4-6 inches of pink fiberglass insulation under the plywood in the attic. Illinois recommends R49-60. I'm trying to decide if R30 or R38 is sufficient for roofline insulation and if I need to add 6-8 inch (R21-28) baffles on top of the plywood to increase the R-value. I'm also concerned about spraying directly to the roof and potential moisture control issues. The company mentioned they would be blocking off the soffit vents and roof caps, and I'm wondering if this is enough consideration to proceed with foam insulation. I'm also considering if I should do the aeroseal in combination with the spray foam.
Quote Details
This option involves spraying 4 inches of closed cell foam on the roofline to achieve an R30 insulation value. - Insulation Type: Closed cell foam - Application: Roofline - Thickness: 4 inches - R-Value Achieved: R30 - Ventilation: Soffit vents and roof caps will be blocked off
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More Details
Category
Insulation
Price
$8,400
Quote Date
February 1, 2026
Location
Illinois
Year Built
1890
Insulation Type
Spray foam
R Value
R30
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