Insulating With Spray Foam

Our bonus room is coming along, and we are finally to the point of tightening up these walls. 

 

Let's talk insulation, shall we? According to the US Department of Energy, the R-values suggested in our climate zone are R30-R38 in the ceiling, and R13-R15 in the walls.  Fiberglass insulation has an r-value of 3.14 per inch of insulation.  Which means that we would need to add 9-12 inches of insulation in our ceiling to meet the recommendations for a cathedral ceiling.  Our roof rafters are only 5 1/2" deep, and we knew we wouldn't be able to get the recommended r-value with out extending our roof rafters with furring strips. 

 

I wasn't too excited about the labor involved with adding furring strips or losing our ceiling height once we went through all that trouble to raise it. 

 

Research of fiberglass insulation convinced us that we should consider other options while we have this room down to the studs.

 

We wanted to close off all gaps that could allow air flow and critters to enter the walls, and we wanted something that would keep our room nice and warm.  Well, as warm as we can get with 3 exterior walls and 4 glass windows.   

Our research led us to closed-cell spray foam insulation (r-value of 6-7 per inch).  Yes, it's a costly alternative.  Since we have 3 exterior walls in this room, we wanted to tighten up this room and stop all drafts, so closed-cell spray foam seemed perfect for an air barrier and to achieve insulation recommendations in our narrow space.  And we wouldn't have to extend the depth of our roof rafters. 

We were sold on the advantages of spray foam.  This project is way out of the realm of DIY abilities so we shopped around for professionals.

We received several quotes from metro-Detroit insulation companies, and one was by far the most knowledgeable, professional, and affordable.

We ended up hiring Excell Insulation to get the job done.  They sprayed the ceiling and walls in our 400 square foot room and cleaned up in less than 5 hours.

First, they installed roof baffles from our ridge vent down to the soffit vents.  This would allow our roof to breathe.  Spray foam insulation does not require any type of venting, but we felt most comfortable allowing air flow beneath our roof.

The contractors went above and beyond the scope of work, too.  They carefully removed all of the old fiberglass insulation from the walls and spread it throughout the attic of our house.  They could have just tossed it with out asking, but they took the initiative to double up our house when possible.

Once the old fiberglass insulation was removed, they suited up in protective suits and respirator masks and sprayed 3-4 inches of foam in the roof rafters and 2-3 inches in the exterior walls.

Not only did they spray the roof rafters and the interior walls, but they also filled the interior wall to the attic.  This was not included on our quote, they just did it the day of because they felt it was a good idea.

We only had them spray the exterior walls since this stuff is pricey.  Interior walls can be lined with plain fiberglass (for soundproofing).

Closed-cell spray foam is not the safest stuff on the market.  It's sprayed with a chemical and it creates an off-gassing that may be considered dangerous.  The workers must wear Teflon suits and respirator masks to spray the foam, and a vapor barrier was placed between the house and the area being sprayed (so I wasn't allowed in during this process). 

There is still a potential for off-gassing while the spray foam dries, so we opened up the windows, stayed out of the room, and kept the vapor barrier in place for a day to allow the foam to cure.

Once the room had aired out, I turned on the heat vents and let the room warm up.

We still have a lot of work to do in this room. And while the temperature in Michigan was quickly falling, having heat would make working in here much more comfortable.

Now that the insulation was complete, we can drywall!

This room will start to come together pretty quickly now.  Drywall, cement board, tile, paint...all the fun stuff is right around the corner!