Chimney leak defies solution
#1
11-03-21, 12:49 PM
Chimney leak defies solution
Hello all,
I have an unfinished attick. You can easily see water leaking down the concreted chimney exterior in a heavy rain. (It can occur with wind or no wind.)
Flashing, shingles and mortar joints appear perfect and the chimney is capped. As I have about exhaused all possibilities, is there any chance a waterproofing would help? It's been my understanding that waterproofing the exterior would only prevent internal leaks, those that run down the inside of the chimney. Am I correct in which case I'd like to avoid waterproofing as I have no internal leaks? Help is much appreciated. If this is the wrong forum please let me know. Thanks.
I have an unfinished attick. You can easily see water leaking down the concreted chimney exterior in a heavy rain. (It can occur with wind or no wind.)
Flashing, shingles and mortar joints appear perfect and the chimney is capped. As I have about exhaused all possibilities, is there any chance a waterproofing would help? It's been my understanding that waterproofing the exterior would only prevent internal leaks, those that run down the inside of the chimney. Am I correct in which case I'd like to avoid waterproofing as I have no internal leaks? Help is much appreciated. If this is the wrong forum please let me know. Thanks.
#2
11-03-21, 01:45 PM
Group Moderator
"Flashing, shingles and mortar joints appear perfect and the chimney is capped."
The leak proves that that is not correct. Without pictures of the roof and chimney above we can't tell you exactly what needs fixing but getting up on the roof and inspecting the area would be a good start.
The leak proves that that is not correct. Without pictures of the roof and chimney above we can't tell you exactly what needs fixing but getting up on the roof and inspecting the area would be a good start.
#3
11-03-21, 04:50 PM
Group Moderator
On a chimney you typically should have step flashing from the shingles to the chimney, and then counterflashing tuck pointed into the brick mortar that laps over the top of that step flashing.
As mentioned, it wouldn't be leaking if all the above, plus the cap and mortar joints were all in perfect condition.
Hard for us to diagnose a leak from 1000 miles away when we have nothing to look at.
As mentioned, it wouldn't be leaking if all the above, plus the cap and mortar joints were all in perfect condition.
Hard for us to diagnose a leak from 1000 miles away when we have nothing to look at.
#4
11-03-21, 08:33 PM
Thanks for the advice. I'll check everything again. But what is the answer to my question about waterproofing? If everything else checks out ok, could porous brick ever be the culprit?
#5
11-04-21, 06:20 AM
It was in my case 2 years ago. Had chimney reflashed by a good company and they seemed to do everything right (and I paid handsomely for it.) I had already repointed any cracked or missing mortar, and the cap was in good shape but I still had leakage.
I applied a waterproofing product that contained siloxanes (it might have been Chimneysaver but I can't remember.) It was available in water-based or solvent based. I wanted to use water-based, but the chimney had been treated years earlier under previous owner so it required using the solvent-based product. I put 2 applications on and have had no leaks since.
I applied a waterproofing product that contained siloxanes (it might have been Chimneysaver but I can't remember.) It was available in water-based or solvent based. I wanted to use water-based, but the chimney had been treated years earlier under previous owner so it required using the solvent-based product. I put 2 applications on and have had no leaks since.
#6
11-04-21, 08:54 AM
Group Moderator
You are throwing the word "waterproofing" around like you bought a value pack at Costco. What is your definition of "waterproofing"? Everything to properly keep the water out (roof, flashing, sealant, chimney cap...) can all be considered waterproofing because their job is to keep water out.
