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Insulating ceiling in unheated basement - your recommendations?

Insulating ceiling in unheated basement - your recommendations?


I am looking for recommendations from the forum regarding insulating an unheated basement. I live in eastern Canada - cold winters! I recently bought a small (approx. 1400 square feet) 2-story home (three years old home) that I will live in for a few years while I build my custom home. I would like to make my first floor floors (laminate and vinyl) warmer and increase the overall warmth/efficiency of the first floor (living room, kitchen, hallway). I am considering the following:

-- Insulating the basement ceiling with fibreglass insulation batts. The ceiling is open.

-- NOT insulating the basement walls - currently no insulation on the basement walls (i.e., no sheet Styrofoam)

Remember the basement is currently unheated and I will not heat it - it is storage space only

I only want to do one insulation technique in the basement due to budget (i.e., insulate the floors with batt OR insulate the walls with sheet styro)

My questions for you are:

Q1. Is my rationale right that batt in the ceiling will make the first-floor floors warmer/improve heat above MORE THAN doing the basement walls with styro sheets? My rationale is that batt in the ceilings is directly insulating the first floor floors whereas styro sheets ion the walls is indirect

Q2. IF I do the basement ceilings should I use R12 or R20? I read on a government website that they reco R12 but I think they assumed that the basement walls were already done with styro sheets

Q3. If I do batt the ceilings in basement, I know it will make my basement colder than it is right now but I don't care - it is only a storage space. But if I use R12 or R20 ceiling batts without the walls having styro, should I worry about the basement becoming so cold that my water pipes freeze? Or am I overworrying?

Thanks - great forum!

Re: Insulating ceiling in unheated basement - your recommendations?

I read an article in the July issue of The Journal of Light Construction that talked about unvented crawlspaces and different insulation methods: foam board on the crawlspace walls versus fiberglass batts between the floor joists. (Your basement, of course, is a basement not a crawlspace but I think the findings should be applicable.) A testing company tested multiple homes in two different climates: Baton Rouge, La., and Flagstaff, Ariz. The study was looking at the energy use and humidity levels. Here was the conclusion:

“To save energy, closed crawlspaces in warm climates should have insulation installed on the walls; in cold climate, the insulation should be placed in the floor system, even when ductwork is located in the crawlspace.”

Here’s a link to the article online:
Sealed Crawlspace Testing Sheds Light on Energy Performance

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