Sign In to join the community | Help
Building Materials

How to insulate 2x4 rafters?

I have a 1925 bungalow in Michigan (climate zone 5).  There are some unfinished crawl space areas in the corners on the upper floor.  They are directly below the roof sheathing and are'/were insulated with fiberglass batts stapled between the 2x4 rafters.  I would really like to get more than R-13 and the current installation is probably providing R-1 with all the missing pieces.  So how can I improve this? 

I was thinking about nailing 2x2s to the 2x4 rafters, then adding 6in of fiberglass.  Can I put something on top of all that? 

Is there some spray foam that I can DIY?

Also, the attic is just a pile of cellulose (I think).  I'm guessing it's way under modern standards. 
Not what you were looking for ? Try posting a question
Posted 2016-01-21T23:04:23+0000  by YoHolmesToFerndale YoHolmesToFerndale

Thanks for your question and welcome to the community.

There's several ways to approach insulating your rafters. One though that isn't usually done by a DIYer is sprayed in insulation. The larger volume is professionally installed, and we don't sell anything save for cans of spray expansion insulation foam that are only good for small cracks and gaps to fill.

If done right, blown-in cellulose insulation adds a lot of R-value in all areas without doing too much work in regards to packing it in, like batted insulation. 

For any option, installing those 2 x 2 furring strips really would be a waste unless the area is very unlevel. 

Another type of insulation you can use is Foamular, made by the same people who makes the batted pink insulation, Owens Corning. 

It comes in varying thicknesses, and its sold at your local Home Depot in the same area and the batted insulation. The thickest we sell in stores in 2 inches. View it below and click here to read more about these easy to install insulation sheets.

In most cases where existing insulation is present,you'll need to remove any older ones, unless they are firmly affixed or hard to reach in the attic space.

Let us know if you have any further questions,


Posted 2016-01-23T18:32:24+0000  by Joseph_HD_ATL
Not what you were looking for ? Try posting a question