As you may well know, we are big fans of cellulose insulation. The Skinny project was the first time we used cellulose and we learned some valuable lessons that we plan to apply to future projects like Avant Garage that Nic has been telling you about lately. As always, we are attempting to continually improve the quality, efficiency and cost of construction. That’s a big part of what this blog is about after all.
We learned two major things while trying to stuff 9.5″ of cellulose insulation into the walls of the Skinny Project.
- 10′ tall x 10″ thick of cellulose is very heavy and wants to make your drywall pop off the studs.
- The majority of the labor installing the cellulose insulation was actually in netting the stud walls prior to blowing it in the cavities.
Let’s dig a bit deeper into these two observations.
The first point is illustrated in the picture below. You can see that the cellulose is bulging the netting out and that the netting is stapled to the face of the studs. This invokes nightmares for the drywall crew. For starters, the crew has to throw their bodies against the drywall in order to press the cellulose back in allowing them to fasten the sheets to the studs. Secondly, due to the netting running over the studs, they can not glue the drywall to the studs to help prevent nail popping. The end result is that it takes longer for the drywall to be installed and we get more nail pops than normal that need to be fixed for the clients once they move in. Neither issue is a huge deal, but still an opportunity for improvement.
The second issue relates directly to the installed cost of cellulose insulation. We did some research and found that the cellulose product itself accounted for about 1/5 of the total install cost we paid to our insulation contractor. The rest is labor and staples for the most part. As stated above, over half of the labor was spent simply installing the netting before a single scrap of cellulose was blown into our walls. You can see how many staples it takes to hold in the netting in the picture above to get an idea of why this takes so long.
Enough talk. On to our hopeful solution to both of these issues. Install the drywall prior to blowing in cellulose into the walls. Simple right?
This came to us when discussing new ideas with the Hybrid Construction crew for improving the air tightness of our envelopes. Installing the drywall first allows the hanging crews to easily glue all sheets to the studs with no hindrances. It also eliminates the need to press in the cellulose to get the sheets to lay flat because there is no cellulose. Once this is done, the insulation crew can come through and simple drill holes for their cellulose pumps just like they do for retrofit walls. They will do this in between hanging and mudding the drywall so there is no extra charge from the drywall crew to spackle over these holes.
We have since verified the effectiveness of this technique with a few other super insulating freak contractors across the country. If our calculations are correct, we should not only save time and improve quality, but we should be able to chop our cellulose insulation costs in half! Not bad.
Anyone out there trying something similar? Share it with us in those comments.
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