The room already has 6in fiberglass R19 ceiling insulation,but it still is very warm.Should I use another layer of R19, or staple the reflective aluminum to the flat attic ceiling?There's 10 ft between the room ceiling n the attic ceiling.Also,the room has west-faced glass window go from ground up 5ft pass room ceiling.For the room portion,I use heat control window film.For the attic portion,can I use something else...like paint,or reflective aluminum?Would it work better than window film?That part does not need to look nice.THANK YOU
This has already been answered in great detail. I thought I would be able to add the ventilation. I can add that there is a temperature controlled attic fan. You set it for the temperature you want the fan to come on and it comes on and shuts off above or below the setting. Good job.
The reflective aluminum will only have an R value of about 3 (for 1/2), R19 would be better. That would get you to R38, which is good. The existing should have a vapor barrier installed toward the ceiling, your added insulation should not have a vapor barrier. Either buy unfaced or remove the facing before you place it. The vapor barrier issue is another reason not to use the foil backed sheets, you don't want to trap any moisture inside your existing fiberglass. As for the window, aluminum would be better at reflecting the radiant heat if you can live with the appearance from the outside. I would still avoid foil backed foam, as it tends to deteriorate when exposed to light and can give off some nasty chemicals. Perhaps just plain aluminum foil affixed with spray adheasive? There is a bubble foam available as well, but it usually comes in large rolls. Painting the window over would be an option as well. Probably would look a bit better from the outside. Clean well with glass cleaner, dry completely. Glass cleaner has ammonia which can react with paint. NO PRIMER. I know that sounds weird, but when painting glass primer can cause the top coat to peel. Two coats of paint. (Painting on glass is actually one field test that we use to test the adhesion of a batch of paint.) Any light color should give the desired effect. Another thing that may help would be to vent the area above the ceiling. This may or may not be practical, but it sounds like heat is being trapped there with no way to escape.
