Help with Sun Room Addition
The previous owners of my house had an addition built. This room is open to the family room and the other 3 walls are mostly windows and a sliding door. It has a cathedral ceiling and the floor is about 5ft off the ground. The walls, ceiling and floor are all insulated with fiberglass batts.
When the outside hits 35 and below it feels like a window is open when sitting in the family room.
The addition does not have many penetrations and I sealed up the 3 outlets. The windows and door are on par for middle of the road double hung and do not leak significantly. (tested with incense stick)
I checked the walls, ceiling, floor with a cheapo thermal gun (or whatever it is called) and found all 3 to be about 4-6 degrees colder than other similar surfaces in the house. Also, specific spots are significantly colder, indicating an air leak into the cavity negating the fiberglass or poor fitting fiberglass.
I did notice through the huge gaps in the drywall around the outlets that the fiberglass fitted poorly around the outlets. So it would not be a stretch to assume other gaps.
The ceiling worries me in that I do not know if it is vented. I know there are soffit vents and a ridge vent. But how does the air travel in between?
I had to replace the roof due to a few leaks and one of the leaks was in this room. I was originally planning to fix the minor water damage to the ceiling and painting it with Killz or similar product. But maybe I should rip it out, check the insulation and venting, add foam board or a radiant barrier and then put up new drywall? This would suck due to it being cathedral...
The floor is covered on the underside by plywood. Part of it is above a little storage room they built, consisting of stud walls with plywood on the outside. No insulation in this storage room. I could rip out the plywood stapled to the underside of the joists and install a radiant barrier as I suspect all it needs is air sealing and then re-staple the plywood. Or install the radiant barrier over the plywood. Or install polysio instead of the plywood. Or make holes in the plywood and blow in cellulose, compressing the batts out of the way. Plenty of options here and not overly much work. But I would still try to get the most bang for my buck. I could even seal and insulate the storage room below the addition for improved thermal performance.
The walls are my biggest challenge. There is a plastic vapor barrier behind the drywall. The siding is fairly new and in great shape, so no polysio on the outside sheathing. All I can think to do is blow in cellulose from the outside, compressing the fiberglass and filling any potential gaps.
There were many problems with the roof and it cost me a small fortune less than a year after buying the house. Bottom line I am cash strapped and can only do diy right now and have limited time.