I’m in the process of re-facing one side of a 2-sided fireplace. After breaking out the brick, and exposing the clay flue tiles I noticed two cracks on two different sides of the same tile. One is about 6-8 inches long, and not more than 1/16 at the worst part. The other crack is about 8-10 inches and at its worst you might be able to get a nickel in it.
My mason says not to worry he will pack mortar around the cracks and there will be no problems. I can’t seem to find any info on this sort of problem, not even caulking for such a situation. Any help would be appreciated.
Don in Sacramento
Replies
Why did the cracks develop in the first place? If there is no expansion space around the flues (i.e., mortar/brick directly packed against flues) that would be one possibility. The cracks can be filled with refractory cement (not regular mortar/portland, etc.) from the outside. Also, you can mix up a very wet slurry of refractory material, drop a sandbag down the flue, with rope attached, then pour the slurry down the chimney, on top of the sandbag, and pull the bag up, forcing the slurry into the cracks you saw and others you may not have seen. You might want to get some mirrors/lights/fiberoptics to check the inside of the chimney and see what problems you have.
There is an air gap around the flue liner. The piece that has the cracks is completely accessible from below, since I've removed the face bricks. I will inspect more and pick-up the special mortar from the brickyard. I try fixing the cracks prior to the mason arriving, so as to do a complete job.
Should I just pack around the pipe, or mortar a piece of veneer brick to the side?
Be more carefull with that refractory than with normal mortar. Wear rubber gloves and keep it out of your eyes. You should read the label too. I believe you need to mist the surface before using it.
As I imagine this scenario, I would don the surgical latex gloves I have, mist the cracks, stick my finger into the bucket, and smear it into the crack from both sides..
Excellence is its own reward!
I'm sure that Piffin means to smear that refractory cement into the crack until it full, just wanted make sure you understand that.
There are also specific curing proceedures for that stuff, so read the directions, or better yet, let your DW read them to you<G>
Anyway, I'd say good luck, but you don't want to rely on luck to avoid a chimney fire. I've seen a really bad one melt the liner, and the rest of the house didn't do too well either, so, be careful.
EliphIno!
Thanks for all the info and help, I will do a full cleaning and then seal the cracks.