Not sure, but what's the depth? I think it's less than 1". I think there's a minimum space required to attribute a specific R-value to an airspace, which also changes based on whether the airspace is sealed or allows for airflow if I recall correctly.
Fiberglass batts
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LLigetfa said:
Lig, I meant overkill for the amount of work involved in creating a mortared durock/brick sandwich. With the multiple layers of durock, no mortar required. The job could easily have been done in the time it has been commented on today.
I think we have had a few folks here post that they used drywall 'hat metal' channel under their hearth.
From the research I did (AFTER making my hearth), at least the top two layers of Durock need to be mortared together. The idea is that the sum of the two sheets plus mortar yields a much more solid base than two sheets screwed together, and this less flexible base will keep the tile / grout from flexing over time. Probably overkill to mortar anything else though, and realistically likely makes no difference, since the stove is a constant immobile weight. But a couple tile forums I looked at recommended it consistently.
Good suggestion if the hearth top is raised on studs. If it is anchored directly to the floor, then this is not needed.
Yea Lowes nor Home Depot had the metal studs here. BeGreen, Using strips of Durock stacked up as studs sounds like a really good idea. Might do that if it will save me some cash. Anyways I got my Durock, lath, and mortar so im getting this thing going. Haha you guys must think I'm a wuss. We only see 20 degrees when it gets real cold here. Up in the northwest yall get below 0 temps and it snows in June. It's beautiful up there though.
TROY COOK
New Member
I was also going to suggest strips of durock<That sounds like the best idea! Just cut 1'' or 1 1/2'' strips and double them up and sister them inline with your studs. 4'' grinder with a diamond blade works good,But do it outside,It's very dusty!
jtp10181
Minister of Fire
1) Home Depot sells metal studs, thats where we buy them from.
2) Has anyone pointed out that technically fiberglass insulation is NOT non-combustible and should NEVER be used in constructing a hearth.
2) Has anyone pointed out that technically fiberglass insulation is NOT non-combustible and should NEVER be used in constructing a hearth.
TROY COOK
New Member
RAMSAY said:
Cut the strips to 3". Smaller than that gets too fragile. Score both sides of the board with a utility knife and snap off the strips.
For the hearth, keep it easy and skip the strips, just stack up the layers of cement board and screw them down to the floor with decking screws.
TROY COOK
New Member
Renovation
New Member
jtp10181 said:
Please tell me more! Technically? What is unfaced fiberglass insulation's ignition temperature? Can you link to any references I can look at?
I Googled around, and was under the impression that unfaced fiberglass was non-combustible, and know someone who has used it, so clarification would be very helpful.
jtp10181
Minister of Fire
RenovationGeorge said:
Its not tested and listed to any ANSI or equivalent non-combustible standard test, thus it is NOT a listed non-combustible.
I never said it would burn or has any listed ignition temperature.
If you look on the spec sheets for products like Durock they list specific non-combustible testing they have passed.
Noncombustible Building Materials: The basic standard used to investigate products in this category is ANSI/ASTM E136, "Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750°C."
Basically in construction something is either "non-combustible" or "combustible". If something was never tested to be non-combustuble then it is considered combustible.
TROY COOK
New Member
This is similar to the stuff I used,It works good for packing around your chimney pipe.I bought it American Fireplace in Minocqua,Wi. Let me know if that helps http://www.gltproducts.com/products/ceramic_fiber_blanket_k-lite/1904RenovationGeorge said:
Renovation
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jtp10181
Minister of Fire
RAMSAY said:
I hope you did not pack that stuff around your pellet chimney unless it is a liner in a masonry flue.
See this post for more info on that topic: https://www.hearth.com/econtent/index.php/forums/viewthread/64010/#732400
Renovation
New Member
RAMSAY said:
Hi Ramsay,
I tried to thank you before, but I guess my reply got lost in the clouds.
Thanks for the info. CertainTeed makes an insulation for high temp applications. They make shingles, siding, etc, so I can get their stuff through my friend the roofer. So there's another option.
Have a great one!
TROY COOK
New Member
No I didn't use that stuff around my pellet pipe.I just used it around my 8'' chimney pipe were it go's though the roof ~ thanks for that info thou that makes sense.
I thought Class A pipe is specifically required to have 2" air space around it and to NOT have insulation in contact with it.
TROY COOK
New Member
Thinking back, I used it around my roof collar not directly around the pipe.and I put it around the framing just to keep some of the heat off the wood.
jtp10181
Minister of Fire
BeGreen said:
Yes, this is true. Even if its non-combustible, you need a 2" air space clearance. Only exception is UL tested components like the fire stops and roof flashings.
Even if insulation is 1" away technically it violates the clearances, could trap extra heat and cause a fire.
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