I just had my chimney cleaned by a local company. The guy said everything was in great shape but recommended sealing the exterior with a watersealing product to prevent the chimney from deteriorating. Are these products worthwhile and necessary?
jdinspector said:I re-read your post. Are they worthwhile? Yes. Are they necessary. No, not if the masonry is in good condition and shedding water properly. Now go back and read my previous post about the type of sealer you should use.
jdinspector said:If the chimney is new and in good condition, I wouldn't get too worried about having it sealed. How much does the sweep want for the sealing?
As far as determining whether it is shedding water properly, if you don't see too much dark water staining (depending on the color of the brick) after a rain and there is a good crown with a good overhang, you're probably OK. It's the intricate chimneys that I see that tend to have big problems. I've put an illustration of a good simple chimney top below...
dvellone said:It looks like you might have some efflorescence occurring in your chimney. This happens when rain water or condensation cause mineral salts to leach out of the mortar or masonry units. Typically it is a clear indication of moisture getting into the masonry structure from behind or above. The moisture migrates outward leaching the salts. In the case of chimneys I see it most often where there is either no cap or where the cap is failing and allowing water in. In the long shot of your house it looks like there isn't a cap. Maybe the angle is hiding it. Water can also enter from failing flashing. It looks like your chimney is built against a rake edge and I can't see a cricket. Whats the flashing like on that side? Could be some of the problem though it looks like the efflorescence is occurring above the flashing point.
The good news is that efflorescence in and of itself isn't a big problem but instead indicates water entry someplace. " Breathable" sealers will allow a minute amount of moisture through at best and in your case, if efflorescence is in fact going on, will cause greater problems by trapping the larger amount of water that's getting into your chimney. The sealer will lead to spalling and rotting of the joints and brick. I might find a local sweep or mason that can check it out closely and see where the water is getting in. It looks like this chimney has been recently repointed and you don't want to jeopardize that investment.
drooplug said:dvellone said:It looks like you might have some efflorescence occurring in your chimney. This happens when rain water or condensation cause mineral salts to leach out of the mortar or masonry units. Typically it is a clear indication of moisture getting into the masonry structure from behind or above. The moisture migrates outward leaching the salts. In the case of chimneys I see it most often where there is either no cap or where the cap is failing and allowing water in. In the long shot of your house it looks like there isn't a cap. Maybe the angle is hiding it. Water can also enter from failing flashing. It looks like your chimney is built against a rake edge and I can't see a cricket. Whats the flashing like on that side? Could be some of the problem though it looks like the efflorescence is occurring above the flashing point.
The good news is that efflorescence in and of itself isn't a big problem but instead indicates water entry someplace. " Breathable" sealers will allow a minute amount of moisture through at best and in your case, if efflorescence is in fact going on, will cause greater problems by trapping the larger amount of water that's getting into your chimney. The sealer will lead to spalling and rotting of the joints and brick. I might find a local sweep or mason that can check it out closely and see where the water is getting in. It looks like this chimney has been recently repointed and you don't want to jeopardize that investment.
The chimney was rebuilt from the ground up. The flue was clean as a whistle until we lit a fire this past winter.
There is a cap on both flues. Though it wouldn't take much for rain to get in anyway. There is no overhanging crown, though.
Are you saying that because I have efflourescence I shouldn't use the sealer?
summit said:to add on that... a cap that covers the entire top.. check out chimcap
dvellone said:drooplug said:dvellone said:It looks like you might have some efflorescence occurring in your chimney. This happens when rain water or condensation cause mineral salts to leach out of the mortar or masonry units. Typically it is a clear indication of moisture getting into the masonry structure from behind or above. The moisture migrates outward leaching the salts. In the case of chimneys I see it most often where there is either no cap or where the cap is failing and allowing water in. In the long shot of your house it looks like there isn't a cap. Maybe the angle is hiding it. Water can also enter from failing flashing. It looks like your chimney is built against a rake edge and I can't see a cricket. Whats the flashing like on that side? Could be some of the problem though it looks like the efflorescence is occurring above the flashing point.
The good news is that efflorescence in and of itself isn't a big problem but instead indicates water entry someplace. " Breathable" sealers will allow a minute amount of moisture through at best and in your case, if efflorescence is in fact going on, will cause greater problems by trapping the larger amount of water that's getting into your chimney. The sealer will lead to spalling and rotting of the joints and brick. I might find a local sweep or mason that can check it out closely and see where the water is getting in. It looks like this chimney has been recently repointed and you don't want to jeopardize that investment.
The chimney was rebuilt from the ground up. The flue was clean as a whistle until we lit a fire this past winter.
There is a cap on both flues. Though it wouldn't take much for rain to get in anyway. There is no overhanging crown, though.
Are you saying that because I have efflourescence I shouldn't use the sealer?
Yes. The efflorescence is indicative of a larger amount of water entering the chimney than the sealers will allow to migrate out. The misconception about sealers is that they somehow have an ability to prevent water from entering the masonry units, but then allow water to escape. They don't work that way. They "seal" both ways so that if you have water entering from above or behind the structure they will inhibit it's escape enough to cause real problems. The "breathability" is somewhat like putting tung oil on your woodwork instead of paint. The tung oil penetrates to protect but doesn't "seal" the wood like a film of oil-based paint would.
I would first get a cap on the chimney with a minimum 2" projection. Then I'd make certain that water isn't entering at the flashing. Next clean the efflorescence off the chimney with a stiff synthetic brush. If this doesn't remove the efflorescence, or if its real heavy you can remove it with 1 part muriatic acid to 12 parts water. Add the acid to the water. Wet the chimney prior to washing and rinse it well after. Don't forget the saftey goggles and gloves - the acid as well as it's fumes are very corrosive. Now leave it as it is through the summer and fall checking to see if the efflorescence reappears. If it doesn't you can then apply your sealer.
jdinspector said:summit said:to add on that... a cap that covers the entire top.. check out chimcap
I agree with this too. Initially, I envisioned a concrete crown on the top of the chimney, similar to what I showed in the illustration I posted. (Incidentally, I use the term crown, when cap is also used. I think that's local vernacular. In either case, it's a cap). Just make sure that whatever you used, it covers the entire chimney top.
I looked at chimcap.com. Those will work fine. However, you have a nice looking chimney. A more intricate copper or other type of metal cap would look great and would also do what you want. Try the local sheet metal shops. Many around me will custom make them for you. I don't have any idea of cost.
drooplug said:jdinspector said:summit said:to add on that... a cap that covers the entire top.. check out chimcap
I agree with this too. Initially, I envisioned a concrete crown on the top of the chimney, similar to what I showed in the illustration I posted. (Incidentally, I use the term crown, when cap is also used. I think that's local vernacular. In either case, it's a cap). Just make sure that whatever you used, it covers the entire chimney top.
I looked at chimcap.com. Those will work fine. However, you have a nice looking chimney. A more intricate copper or other type of metal cap would look great and would also do what you want. Try the local sheet metal shops. Many around me will custom make them for you. I don't have any idea of cost.
I have caps up there already.
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