House in Progress Diary

Chimney Repair Advice

After discovering last weekend that the interior chimney on the second floor had deteriorated horribly, we quickly got a contractor in today for advice. His advice was largely consistent with the comments people posted on our site. (Thanks Gary, POPS"30", Kristen, Stuart and Marty!)

At first he was thinking we could get away with a aluminum liner (cheaper) but when he saw that our chimney was originally lined with tile he recommended a stainless steel liner. Aluminum liners are cheaper, but not as ridged or durable as stainless steel.

From what we've read, one of the problems is that the unlined venting of older chimneys is just too wide for modern boilers. The extra space allows gases to linger in the chimney, and moisture then seeps into the bricks or mortar, causing deterioration, as in our case. This is dangerous because fumes then leak through the brickwork (and into the house!) instead of up and out. Yikes!

The good news is that the contractor we spoke to thought we could get away without rebuilding our chimney above the roofline (even though the more recent tuckpointing job is so poor). Rather than removing and replacing it, he suggested having the mortar above the roofline ground out and re-tuckpointed. They would do the same below the roofline outside, too. An acid wash would help to get rid of the efflorescence (white stains). They would also repair the wall of the chimney on the inside of the second floor.

This wouldn't look perfect but would still be an improvement. Rebuilding the chimney wouldn't be perfect anyway, because they don't make 8" bricks to match ours anymore.

Posted by aaron on May 13, 2004 at 10:28 PM