Home Improvement Qs: Off-topic discussion forum: Grassroots Motorsports Magazine

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April 7, 2009 10:41 a.m. Lennyseleven New Reader

Im tearing out an old plaster wall and putting in new insulation and drywall, and wondering if the new pink stuff and drywall is going to be better insulating than that old thick plaster and some old old blown in insulation.

But my real question is, I have a wood burning stove and am wondering if there is a certain type of drywall I need to buy to install near the stove and the chimney coming through the wall? also is there any type of sealant or caulk that can withstand the temps around a metal chimney, it looks like theres some openings that need to be sealed up.

....get stuck on inside projects when we get 6 inches of snow in april....

thanks
April 7, 2009 10:51 a.m. ignorant SuperDork

There is Fire Rated drywall. It is thicker than standard so matching seams is a pain. It's 5/8" I believe. Check your local building codes about this job. You'd hate to do it and then have to tear it out.

There is also special flanges and caulk to seal up the penetrations. A fireplace/wood burning stove store can really help.
April 7, 2009 11:31 a.m. fiat22turbo SuperDork

There is also a fire shield I've seen used, basicaly a sheet of steel or SS that you put up behind the stove.
April 7, 2009 12:12 p.m. Lennyseleven New Reader

yea theres brick directly behind the stove but im just wondering about the wall where the chimney comes through and the ceiling above.

thanks guys
April 7, 2009 12:19 p.m. Lennyseleven New Reader
April 7, 2009 1:34 p.m. DILYSI Dave SuperDork

Dunno what Code says, but I'd put up 5/8" Drywall on the ceiling and two adjacent walls. Also - fresh insulation will be better than the old compacted stuff.
April 7, 2009 4:12 p.m. ManofFewWords Reader

This is a case where you should be asking your local building code officer, not someone on the internet. A reputable stove store will help you as well.
April 7, 2009 4:31 p.m. SVreX SuperDork

Are you asking about thermal insulation or sound insulation?

The drywall will not insulate as well as the plaster. The fiberglass should be better than the rock wool.

The issue isn't what type of drywall to use near the chimney. The issue is what type of chimney to use near the drywall.

I'm betting that is a single wall metal chimney, with wood framing nearly touching it. BIG NO-NO. Codes have changed since your house was built, and generally require triple wall chimney construction, with minimum clearances to flammable materials.

Ask a local inspector or person trained and licensed in installing metal chimneys. DO NOT TRUST INTERNET ADVICE WITH THE LIVES OF YOUR FAMILY.

Fire rated drywall is resistant only when used in specific assemblies tested by the UL. It is NOT fireproof unto itself. The paper surface burns.
April 7, 2009 7:29 p.m. ohioboy New Reader

I'm not signing off on anything, but it looks like you do have an appropriate thimble assembly for the wall penetration (the larger pipe assembly in the wall with the trim plate piece that the smaller 6" stove pipe is going through).

There may be a mfr's name or a certification on it - you can use that to track down the clearance to combustibles (which is probably zero since it was made to go through a wall which is more than likely combustible). Also, you won't have to but the drywall right to that outer pipe as that trim plate will allow you to leave a hidden gap that you can fill with fiberglass.
April 7, 2009 9:53 p.m. Lennyseleven New Reader

Yea Ive got a stove store round the corner I checked with today, but always like get a quick answer too. There is a larger pipe around the vent itself so that gives alot more clearance and like you said that trim peice gives a little more.

Dont worry I wouldnt trust you guys with my life. hah
April 7, 2009 9:53 p.m. Lesley SuperDork

I second getting in a qualified inspector. My woodstove and brick surround looked very much like yours, except the brickwork goes all the way up to the ceiling. Recently my insurance company merged with another, requiring a building inspection. Although the stove was there when I bought the house and was fine with the old company for the last 20 years, they refused to renew my insurance until I'd either spent mega bucks upgrading not only the stove and the area around it(including a liner for the chimney which was new when I purchased) or put a cap on the stove so it couldn't be used. I opted to have it capped (for now).