Basement Stairway
bosshog2212
| Posted in General Questions on
I have colder air coming up to my main floor from my open basement stairway.
At the bottom of the stairs there is a door that closes the basement off.
My questions are…
Should the back side of the stairs themselves be Insulated? If so, with what type of insulation?
This happens with the basement door shut. It’s worst when open obviously. It is a finished basement but I can get access to the back of the stairs.
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Replies
bosshog2212,
Cold air doesn't want to rise. It's doing so because of the Stack Effect, that is because of air-leakage through your building enclosure, probably mostly through the rim-joist area in the basement , and the ceiling of your top floor. What you are trying to do by air-sealing and insulating at the basement stair is to stop that movement between the two spaces, but the place to do that is where it enters or exits your house. Air-sealing, concentrating primarily in the basement and upper story will eliminate the problem.
Seems to me your basement must be very leaky or it would be the same temp as upstairs.
1 Fix the spots where outdoor air is leaking into the basement.
2 Insulate the basement walls so it stays warm.
3 install furnace vent in the basement so that it stays warm if needed.
Walta
Definitely! Insulating the stairs will create a thermal barrier, reducing heat loss from your main floor and preventing cold air from seeping through. This will improve comfort and potentially save on heating costs.
Types of Insulation: https://www.homeadvisor.com/r/proper-attic-insulation/ geometry dash world
Would you use rigid foam board?
bosshog2212,
Remember that if you use foam, it needs either an ignition or thermal barrier.
https://www.greenbuildingadvisor.com/article/thermal-barriers-and-ignition-barriers-for-spray-foam
You're going to have to air seal foam or fluffy insulation, right?
Since it's living space, not attic or crawl, code says it would have to be thermal barrier if you do rigid foam. That's 2" Rockwool Comfortboard 80, or 3" Rockwool/Thermafiber, 1/2" drywall, 1/4 hardboard, structural plywood on back side as an assembly. Is your stairs fire assembly with riser and tread board?
Seems to me fiberglass insulation would be the only way to go.
Alid1988,
The stairs probably represent 10% of the area of the floor separating the two spaces. Insulating that area alone will have a negligible effect. Air-sealing will do more, but as we have pointed out, that's the wrong place to be trying to solve the problem. The thermal and air-barrier should be at the perimeter of the conditioned enclosure.
When you insulate under the stairs don’t forger the do the walls of the stairway R 38 all around would be great! O yah be sure to upgrade the door to something with weather stripping and a foam core.
LOL
Walta
Yes, insulating the back side of the stairs can definitely help reduce the cold air flow from the basement slope game