Insulating internal stairways
I’m building a 28×36 “cape like” house on top of an existing 15yo daylight foundtation in zone 6. It will have a stairway leading up to the main floor from the now inefficient basement and another leading up to the “livable attic” which has raised heel trusses. In the attic will be a bedroom on one end and a half bath on the other. I may have to use polysilo insulation because there isn’t enough room for much else since it’s 7’6″, and to be in code, I have to maintain 7′. I’m open to ideas here.. The attic floor will have r60 cellulose everwhere I can fit it.
The 2×6 main floor will have either a double wall or mooney wall. Still on the fence.
My question is around the stair details. I’ll have a door at the top of the basement stairs.
I’ll also have a door at the base of the full attic stairs. How should I insulate these areas and what types of doors should I use?
Heck, while I’m on the topic of doors. I could use some suggestions on insulated external doors as well. And a garage door.
Thanks!
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Replies
If you're putting living space, including plumbing, in the attic - then why are you putting R-60 in the cellar floor? The attic trusses are the thermal boundary. Then you don't need anything more than an interior door at the attic stair.
If the basement is unconditioned space (no plumbing?) and the thermal boundary is at the first floor, then you'll need an exterior insulated door at the basement stairs. Therma-Tru makes fine insulated entry doors, but I would recommend fiberglass rather than steel for durability, with an adjustable sill.
Robert, Just to clarify, the attic loft is a ten foot wide tunnel in the middle of a 28' wide attic. Which leaves 9ft on either side to insulate, in the unconditioned, vented attic. I would love to keep the plumbing out of the basement to avoid having to heat 1000 sqf of nothing. I have 20in floor trusses which gives lots of opportunity for insulation in the basement ceiling. I've got a septic pipe and a well inlet to contend with. Maybe a heater wire and some insulation around them would help me with my mission for a cold basement.
Stephen,
As Robert pointed out, anywhere a door separates conditioned space from unconditioned space, you should install an insulated door (an "exterior" door or "entry" door). Fiberglass is better than steel.
Here's an article on garage doors: Energy-Efficient Garage Doors.