Vapor Barrier & Radiant Barrier

When I had made the decision to install a fan in the bathroom, I left the vapor barrier open by the awning window in the gable peak above the bathroom, thinking that the vent for the fan might go there. But no, of course not. When I opened the fan I purchased and read the installation directions, it became clear that the fan had to be vented under the eave on the north wall--a wall I had already sealed up with the vapor barrier. Of course, because that is how this project (and my life) work.

Now, though, I have finally finished installing the vapor barrier on the walls of the bathroom.

Next up: Installing the radiant barrier on the ceiling.

For those who haven't been following along for years, I am using radiant barriers on all surfaces of the JayBee. A radiant barrier adds an extra 30% to the R-value of the insulation in a surface. The radiant barrier I installed on the walls is on the exterior underneath the housewrap. Since it is perforated and not a vapor barrier, I installed plastic on the interior as the vapor barrier. The radiant barrier I used under the subfloor and that I am installing on the ceiling is a bubble-wrap type that doubles as a vapor barrier.

I started with the easy stuff--the ceiling of the bathroom bumpout...

..and the ceiling of the bed alcove bumpout.

To prepare the radiant barrier for the ceiling, I cut long strips, and added a little extra to make each piece large enough to cover half of the ceiling.

Beginning to install the radiant barrier over the bed alcove and reading-nook/guest-room loft.

Preparing a strip of the radiant barrier is pretty easy. Stapling the radiant barrier to the rafters is not very hard either. Covering every staple with tape, and sealing the radiant barrier to the plastic on the walls with tape--very time consuming.

I think installing the ceiling boards over this radiant barrier is going to be challenging. I like being able to see through the plastic on the walls--to see where all the framing is. Anticipating not being able to see through the radiant barrier while installing boards on the ceiling... hmm. We'll see how it goes.