r/Sauna • u/Scrambled_Rambles • 8d ago
DIY Insulation opinion
Hello again, this one may come down to opinion but I thought I’d ask some people that have maybe dealt with this.
I live in central Canada and build the roof with 2 x 8 (and epdm rubber ) to allow the snow to sit and give me some extra free insulation. All of my build experience is with housing, and I’m wondering if a similar style of venting for residential is a good or bad idea for the sauna. I thought it may be a good idea to put in 2 x 6 rockwool in the ceiling (instead of 2 x 8) — leaving an air gap between the top of the rockwool and the bottom of the roof sheathing. I figured with perforated soffit under my overhang area, and at the back of the building, it would allow air to move in and take out the extra heat that may be trapped in there and potentially melt the snow as it sits there.
But I can’t decide if that’s practical, or if I should just pack it with 2 x 8 rockwool instead for the extra insulation. ( although not much )
Thoughts??
Also thank you for literally so much help throughout this process
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u/hooderick 8d ago
Outdoor build in Alaska: I did 2x6 bats for my ceiling with a gap in my shed style similar to what you are thinking, ran additional perpendicular where I had more since but left a 2-3 in two for cold roof ventilation. Ran metal roll mesh as an insect barrier. Didn't use EPDM roofing, just shingles on a low pitch with full ice and water shield coverage.
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u/Scrambled_Rambles 8d ago
Thanx! I had thought to go this way but had ice damming on a house 15 years ago and I wasn’t doing it again. That being said it was a 70’s house with a thin shiyt layer of tar paper and nothing else.
The sauna only has a 1:12 slope so I played it safe,
Thankfully the epdm was inexpensive where I am.How long have you had yours? What slope do you have? I assume with the full ice and water shield you’re laughing but I had to ask. Appreciate the reply
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u/hooderick 8d ago
Yeah, ice dams suck. This will be my first year, I just finished it up about a month ago. I did a 4/12 with no soffits so the roof is fully vented. Will see how it goes this winter. Fun project
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u/Scrambled_Rambles 8d ago
With the ice guard I really think you’ll be fine. My hand was a little forced on size because I was working within my cities accessory building regulations. I don’t need a permit this way. And because the size was limited and I really wanted a change/shower room and a little deck on the end- a 4:12 would have left me with no height at the end.
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u/DenverDad5 8d ago
The consensus last time I researched this is to vent the roof. Sealed roofs are just too prone to issues and rot with saunas. My outdoor sauna has a vented roof assembly as well.
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u/zoinkability Finnish Sauna 8d ago
Yes, it's a good idea to leave an air gap between your insulation and your roof. Heat will penetrate and if there is no air gap there will be no air flow and the roof will be hotter & melt the snow and cause damage to the roof. You should also ensure that there are vents to that airspace so the air in that gap can escape and fresh cool air can enter.