by Tim Fulton on January 29, 2009
Catch up on this project here:
Insulating the Attic – Part 1
Insulating the Attic – Part 2
At the end of the last article, we left things ready to blow insulation. Well, almost ready at least. There were still a few things to be done.
The first thing to be done was to build a platform to retain some storage. So, a simple frame was built. This will allow some storage around the the attic access. With the cellulose being blown in over the top, now was the time to do this if we wanted any storage in the attic.
Next on the list was to make some sort of dam around the attic access to stop the cellulose from falling out. I decided to do this with rigid foam I had. It could easily be done with cardboard or wood too.
Alright, finally time to do something with this insulation thats been sitting in my garage for the past few months when I got it on sale. I ran back to the same home improvement store I got the insulation from one night after work. I picked up their cellulose blower which I got to use for free since I bought the insulation there.
The rest was pretty simple. I read the instructions that came with the blower. Set it all up and had my wife load the blower while I blew it in. The actual blowing part is incredibly easy and even a bit fun.
Now, we have a good 15 inches of insulation over the 6 inches of rockwool/fiberglass. Of course it will settle some time. But, this should increase the insulation in the attic to around R-60 which was the initial goal of this project.
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by Tim Fulton on January 25, 2009
Its been a few weeks since we cleaned and sealed the attic in Part 1 of our series. This is how the roof looked in the middle of December. As you can see, the eves have more snow on them than the middle of the roof. This is a clear indication of heat loss through the attic.
As I mentioned in part 1, there were some odd areas to insulate. So, let me explain further. In my house, the roof doesn’t meet the walls at the top of the ceiling of the second story as it would with a normal two story house. Instead, it comes down about a foot and a half. The above picture is a rough cross section.
So, I need to insulate the yellow area as much as possible since it is only about five to six inches thick. I ended up choosing to use polyisocyanurate (polyiso) rigid foam as it has the highest r-value I could find (6.5 per inch). Two one inch thick sheets would be put down over the rock wool insulation that was already put down. This would give me approximately ~R-16 in that area. This will still allow roughly a 1″ gap above the rigid foam for an air passage which is a necessity.
The actual fitment of the rigid foam boards was quite easy. I used 4′x8′ sheets and cut them equally into four pieces. Then, to make everything fit, I needed to cut a small strip off of the end so it would slide down fully. You can see this in the lower right of the picture. To ensure that there was a sufficient air gap, I used the cut off strip and slid it in above the foam board as a spacer. It fit perfectly, and things are almost ready for the cellulose.
by Tim Fulton on November 15, 2008
The next project on the list for ER’s house is adding attic insulation. The house as is has about 1.5″ of rock wool insulation, and about 5″ of fiberglass above that. So, the attic is insulated to about R-19ish. This is a far cry from the recommended R-50 to R-60!
So, to remedy this situation, I decided it would be best to blow cellulose over the top of the fiberglass. I chose cellulose for a number of reasons. Cellulose is a nice environmentally friendly option for insulation. Installing cellulose is cheaper than fiberglass rolls, and its much easier to install. It also stops airflow much better than fiberglass. In my book cellulose wins hands down.
The first thing that needed to be done was to clean the attic. The previous owners only left a few boxes and carpets in the attic so that went quick. However, the roof on the house was just redone several months ago and the roofers made a horrible mess of the attic. There were tons of nails, wood chips, and more dust than you could ever sneeze at. So, I got out the broom and shop vac and started cleaning things up. To help with the clean up of the nails I got out a large magnet I had laying around. This did pretty well picking them up. This is what it looked like before.
The next step in this process was to seal the attic. This means pulling back the fiberglass and rock wool and filling any holes or gaps that might let air pass easily into the attic. This is easily done with either caulk for small holes and gaps, or expanding foam (Great Stuff) for larger holes and gaps. I recommend finding where all the wiring goes, because they have to drill holes to get the wires through the ceiling. Also, junction boxes can leave huge gaps as well. Seal them up so air doesn’t get through! Here are a couple examples of the work and what I found in my attic.
Its very easy to tell if air is getting pulled into the attic. Just look for areas of dust accumulation on your insulation. Its very evident when you pull it all up.
With the attic all sealed up it is now ready for insulation. Of course there are snags in the plan and some odd areas to get insulation in. Check back later to see how that goes.
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