After a couple of coats of a good primer, itā??s time to cut the holes for the air intake and vent fan. The hole thru the roof for the fan needs to be sealed real well so, after I cut the holes through the double-layer ceiling, I wrapped a piece of 6ā? duct with paper and foil and filled the roof space with expanding foam sealant. This gave me a nice ā??tubeā? thru the roof and I can now easily caulk the vent pipe to seal against light and air leakage.

Iā??m going to line the interior with reflective material. The reflective material is rather difficult to work around or on, so Iā??m going to temporarily install the ducts and fan to make sure everything fits right. Itā??s a good idea to use short screws when taking the fan in and out making it fit. That way, the permanent screws you use will be going into fresh wood instead of a used hole.