More air sealing before drywall/plaster?
Steve Snyder| Posted inPassivHauson
I am building a small 750 square foot cottage and have achieved 1.24 ACH at 50 pascals before applying the drywall/plaster finish. Is there a standard target ACH before the walls are finished? The walls are insulated with foam and I am trying to figure out whether we can achieve .6 ACH by finishing the walls or need to do further air sealing.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Steve,
Congratulations. You've done a good job.
The best way to determine where your remaining leaks are located is when the blower door is depressurizing your house. Did you walk around the house, feeling for air leaks with your hand? That's usually the best way to find leaks.
If your hands are calloused from years of carpentry, you can use an incense stick instead.
Once you know where the remaining air leaks are located, you can come up with a plan for further tightening.
But really, Steve, you're doing pretty good, so I wouldn't worry too much. Your cottage isn't going to cost much to heat.
My energy advisor who did the blower door test suggests that the remaining leaks could be dealt with by simply hanging the drywall, applying the plaster and completing the wood trim around the windows...that I wouldn't need to do more air sealing to hit the target of .6 ACH at 50 pascals.
So I wanted to find out whether there is a benchmark for tightness after insulation but before finishing the walls. We did do some blower door air sealing but called it good after getting to 1.24 but now I am not so comfortable that we will reach .6 after finishing the walls...
Are you going to follow the Airtight Drywall guidelines and gasket top and bottom plates, wall partitions and around windows and doors? If not I don't think you will cut the ach50 in half, to your credit, 1.24 ach50 is quite a tight house.