Hi,
I got an Aspen C3 installed in a vaulted ceiling large living+dining room, ~16' base-to-chimney, with another ~10-15'(?) above the roof (think mild A-frame-ish house, and the stove is set diagonally in one corner of the house).
I've done two break-in fires. The first was very controlled, I think I saw 500-600 F on the (uninsulated) cook top on top of the C3. Last night I did a larger one, with cook top temp reaching 800+. From this other thread, that looks to be ok and folks seem to report no problems just relying on VC's "as long as its not glowing its fine" technical standard.
My question is about stove clearances and safe temps. Immediately surrounding my C3 is currently drywall covering wood 2x6 framing, which needs to be covered up. Clearances are something like 4.5" to the nearest stove corner (diagonal installation) and 10" to the double-walled stovepipe. All within VC's installation manual requirements, (3" and 9", respectively) with a bit to spare.
On the first fire, an IR thermometer measured temps up to 170 on the drywall. After observing that, I realized I'll need to cover up the drywall. For the time being, I added a 1" batt of mineral wool insulation on each of the two surrounding walls. (See attached pic.) That leaves .5" clearance to spare to the stove corners and the stove pipe. During last night's break-in fire, the IR thermometer measured the mineral wool at 200+ degrees. I know that's well within the heat tolerance of mineral wool, and I lifted the wool for a sec to take the drywall temp behind it, which barely broke 100. All good so far - as an interim solution.
My Q is the mineral wool needs to be covered up if it's gonna stay there, or possibly I could replace it with like .5" cement board, and then a finish layer on top. The whole hearth was planned to be a home made clay plaster finish, so we ideally wanted the wood stove surround to also be clay plaster. Tile would also work (but installing tile would involve a learning curve for us, and we have tons of other projects around the house without adding this one). Problem is, with R15-ish mineral wool getting up to 200+ degrees (on what was ostensibly a break-in, milder fire in the C3), I'm not sure that clay plaster+cement board will hold up to those temps repeatedly, and/or if it will keep the drywall and underlying wood 2x6s at a safe temp over the long term. (I've seen info that typical gypsum drywall isn't meant to go above 125 degrees.) I've seen this setup proposed, which uses an air gap as insulation to the drywall and wood framing, which even boasts reducing manufacturer-required clearances. Does anyone have experience on a cement board+finish layer, with or without the air gap setup linked above, when temps are getting this high on surrounding surfaces? What kind of high temps do folks observe on their wood stove surrounds (those with tight clearance setups)?
If we keep the mineral wool insulation in place, I imagine fashioning a three-sided container for it that fastens to the wall and keeps it enclosed. Probably made of metal, like corrugated aluminum or corten aged-looking steel. We might have a challenge matching that well with the rest of the clay plaster-finished hearth (though, clay/adobe + wood + sheetmetal is a common aesthetic for homes in many places around the world). The metal surface would give us an added bonus of reflecting more of the radiant heat back into the room rather than it just getting absorbed in that corner of the house.
Welcome any thoughts, and thanks for reading this long post!
I got an Aspen C3 installed in a vaulted ceiling large living+dining room, ~16' base-to-chimney, with another ~10-15'(?) above the roof (think mild A-frame-ish house, and the stove is set diagonally in one corner of the house).
I've done two break-in fires. The first was very controlled, I think I saw 500-600 F on the (uninsulated) cook top on top of the C3. Last night I did a larger one, with cook top temp reaching 800+. From this other thread, that looks to be ok and folks seem to report no problems just relying on VC's "as long as its not glowing its fine" technical standard.
My question is about stove clearances and safe temps. Immediately surrounding my C3 is currently drywall covering wood 2x6 framing, which needs to be covered up. Clearances are something like 4.5" to the nearest stove corner (diagonal installation) and 10" to the double-walled stovepipe. All within VC's installation manual requirements, (3" and 9", respectively) with a bit to spare.
On the first fire, an IR thermometer measured temps up to 170 on the drywall. After observing that, I realized I'll need to cover up the drywall. For the time being, I added a 1" batt of mineral wool insulation on each of the two surrounding walls. (See attached pic.) That leaves .5" clearance to spare to the stove corners and the stove pipe. During last night's break-in fire, the IR thermometer measured the mineral wool at 200+ degrees. I know that's well within the heat tolerance of mineral wool, and I lifted the wool for a sec to take the drywall temp behind it, which barely broke 100. All good so far - as an interim solution.
My Q is the mineral wool needs to be covered up if it's gonna stay there, or possibly I could replace it with like .5" cement board, and then a finish layer on top. The whole hearth was planned to be a home made clay plaster finish, so we ideally wanted the wood stove surround to also be clay plaster. Tile would also work (but installing tile would involve a learning curve for us, and we have tons of other projects around the house without adding this one). Problem is, with R15-ish mineral wool getting up to 200+ degrees (on what was ostensibly a break-in, milder fire in the C3), I'm not sure that clay plaster+cement board will hold up to those temps repeatedly, and/or if it will keep the drywall and underlying wood 2x6s at a safe temp over the long term. (I've seen info that typical gypsum drywall isn't meant to go above 125 degrees.) I've seen this setup proposed, which uses an air gap as insulation to the drywall and wood framing, which even boasts reducing manufacturer-required clearances. Does anyone have experience on a cement board+finish layer, with or without the air gap setup linked above, when temps are getting this high on surrounding surfaces? What kind of high temps do folks observe on their wood stove surrounds (those with tight clearance setups)?
If we keep the mineral wool insulation in place, I imagine fashioning a three-sided container for it that fastens to the wall and keeps it enclosed. Probably made of metal, like corrugated aluminum or corten aged-looking steel. We might have a challenge matching that well with the rest of the clay plaster-finished hearth (though, clay/adobe + wood + sheetmetal is a common aesthetic for homes in many places around the world). The metal surface would give us an added bonus of reflecting more of the radiant heat back into the room rather than it just getting absorbed in that corner of the house.
Welcome any thoughts, and thanks for reading this long post!
![[Hearth.com] Clearances with Aspen C3](/talk/data/attachments/340/340925-7722cd51d6affae0aec86b495858629b.jpg?hash=Hkp9MCfReD)
