Answer to Attic Spray Foam issue

Answer to my post from last night. After going through some document copies from the homeowner, the foam manufacturer is Demilec. The product used was Sealection 500. The attic space must be conditioned with the use of this product. No floor (ceiling) insulation allowed. This particular attic has fiberglass batt ceiling insulation. Also, the roofing is 14 years old, manufacturer appears to be promoting application for new construction. Link attached.

Ok…what was the question?


My original concern/question was related to the application of spray foam on the roof underside or sheathing. i have never observed this application in my area, although i do recall seeing it on This Old House. The attic inspected apparently does have issues with the foam installation, as it is not a conditioned space with the existing ceiling insulation and two open gable vents, one with a powered fan. As always, I appreciate all opinions and input.

Basiclly, you are extending the building envelope to the roof decking. The attic area should not be ventilated (no soffit, roof or gable vents open) and the attic floor / ceiling should also not be insulated (although ceiling can lights should be sealed).

If the whole house is foamed then there should be an air exchanger installed at the forced air furnace so as to allow for propr ventilation.

Air leakage is one of the most common causes of bad insulation. Foam stops this. The underside of the roof should be sprayed with open cell foam, walls with closed cell.

Hope this helps;

Try polyurethane foam for insulation.Ultimate linings Spray foam Insulation is a polyurethane foam that is pumped into your home so that your walls, ceilings, will be insulated well. This type of Insulation will help you to keep the cold outside during winter and help keep the heat out during the summer months. After all no one wants to be too hot or too cold. At one point only trained professionals could do this. Now they have the do it yourself kits.