We are currently adding an addition to our 50's style ranch and during this process I have thrown away all the old insulation in the attic to start over. One part of home with be a cathedral ceiling and there will be no floor space above that area but the other half of the home will contain our new heating/AC unit. There is only 2X6's right now that used to contain some sparse plank flooring, I ripped all the planks out and purchased some cheap plywood to put back down for attic storage. My question is, going with the recommended R Value for my area the insulation is obviously way above the rafters in the area that I wanted to floor for storage. Will it be an issue if I use the thicker insulation and simply lay the plywood over it? I have read that compressing the insulation kills the R value and there should be an air space, should I use smaller encapsulated insulation like R-28 for the area that I plan to floor instead? I was looking to get the correct R-38 value but I do not want to do the job incorrectly. I also do not plan on installing the plywood permenately, just a few screws in each piece to hold it in place.

Thanks in advance,
Mike.

 

Anyone? Any tips, installation instructions? I need to get this done soon!

Thanks

 

You could put in R-19 in the floor and floor over it. The R-38 is just recommended. If you want the R-38, you can add over the the R-19 but it must be unfaced insulation. Also, you want to lay it perpendicular to the floor joists for better coverage.

If you want to floor over that, then you have to build up the floor. The way to do it is very simple and it is done in sections. Take five 2" x 6" boards 8 feet long. Cut one 2 x 6 into equal halfs. Create a rectangle with the two 4 ft. lengths and two 8 feet length and nail together. With a tape measue mark on both 4 feet lengths 16 inches and 32 inches from either end. The other two 8 feet lengths get nailed there. If you were to stand this up, it's exactly how a wall is framed. You basically have a rectangle that's 4 feet wide and 8 feet and 3 1/2 inches long.

Slide or drag this frame to the area on the attic floor you want it and tack it down to the floor joists. Insulate the cavities and make sure it's perpendicular to the floor joists. Make similar sections and slide into position untill you have the desired floor area. Once you have that, then install plywood over these sections. Making sure the plywood overlaps two sections in order to tie them all together for a nice solid floor, that you could put a piano on if you wanted.