Customer finds me in a parking lot and asks me if I can tuck point the mortar inside a fireplace.
I said I’d look into it.
I have not yet been out to the house to look at it.
I have learned that there is a special mortar to use which my yard has on hand.
If as much of the mortar is missing as described, then it seems reasonable to assume that there is a fair amount of soot in the joints.
Does the soot need to be cleaned out before tuckpointing?
If so, how thoroughly??
Any other thoughts?
Thanks.
Rich Beckman
Another day, another tool.
Replies
Any tuckpointing needs the joints to be cleaned out to solid mortar. For the inside of a firebox, I'd start with a wire brush to get the soot and really loose stuff. (Tip - if you open the damper a bit the rising air will take some of the lighter soot and dust with it).
Then use a chisel to scrape the rest of the loose stuff out of the joints. The tail-end of a rat-tail jointer works well also. Wire brush, then regular brush again to get the last of the loose stuff out.
I've never mixed fireclay (or refractory cement) with existing, presumably, regular mortar before. I can't imagine there'd be a problem, but I just don't know. If they're firebricks, you'll want to dampen 'em first. They suck up water like crazy, and you won't get a good bond. A wallpaper brush works well for this.
I've been in the Handyman Business for a few years now, and I generally find a way to politely refuse requests like that one.
If the fireplace is built properly, then it is lined with firebrick. And you'll need to use a mixture of fireclay and portland cement. And if you leave the smallest of hairline cracks, the house could burn as a result.
If, on the other hand, the fireplace is not built with firebricks, then it might be inherently dangerous from the getgo -- with or without your repair. But if it has your repair, then the fire could be construed to be your fault.
Good luck.
Unless you're the lead dog, the view just never changes.
Rich,
I think ya gotta wear some dark sunglasses. You keep running into these "customers" in parking lots.
Actually, this is not a difficult job. And not dangerous, 'cause the firebox is without the mortar joints now, and hasn't burned down. Just clean with a wire brush as prescribed or use muriatic acid with windows open and neutralize after with baking soda. Use refractory cement or type "s" and point away.