Masonry chimney repair.

August 21, 2009 11:49 AM

Which should I use to repair my chimney? Mortar, cement.......?

I need advice with a small chimney repair job. The base of the chimney in my cellar has disintegrating bricks at it's base. It has been repaired once before I owned the house. Any masonry
experts out there?

posted by boby to Home & Garden (5 answers total)

If the chimney is disintegrating outside, what's it doing inside? I think you ought to have someone come out and look at it. They will probably give you a free quote for what they want to do. If it's just some mortar or whatever (which i doubt...), then you can say 'no thanks', and do it yourself. But really, if it's getting messed up on the outside, it might be falling apart inside. Dying from CO poisoning really sucks.
posted by Geckwoistmeinauto at 12:07 PM on August 21, 2009

I'm no expert but the guy who redid our chimney says that when people try to do their own repointing, they sometimes use leftover cement, straight out of the bag. It's too hard and causes the faces of the bricks to pop off. I'd call somebody.
posted by bonobothegreat at 12:35 PM on August 21, 2009

If this is below the firebox, and the ash pit (if you have one), then the CO problem is not as important as the problem of a 25 foot tall stack of bricks resting on crumbling ones.

If this is just a small area, say a patch of six or so bricks, then you can probably chip it out and replace with new bricks and mortar. However, since this problem has happened before, I think you should hire a mason to inspect and repair it.
posted by Midnight Skulker at 12:35 PM on August 21, 2009

Best answer: Those bricks are failing because moisture is coming in from behind. The paint on the bricks makes matters worse. Besides masonry repair, you probably need to deal with water infiltration issues. Are you in an area that gets really cold in the winter? Aside from the disintegrating brick, there is an underlying problem that needs expert diagnosis.
This is really a job for a chimney specialist. In any case, never use cement based patching on brick. You need a special soft mortar (traditionally lime based) for old brick. You should also see if there is a source for used brick in your area. You can find matching materials that way.
If you want to do further research on your own, look up masonry renovation under the Masonry Institute of America. Then you can be armed with facts. You can also find a mason that knows what they're doing.
posted by Carmody'sPrize at 1:03 PM on August 21, 2009 [1 favorite]

Response by poster: Thanks for the advice. I thought it could be a "do it yourself" repair but I'll call in some experts.
posted by boby at 10:59 AM on August 22, 2009