Weather proofing field stone chimney

[TKeller]

I have a fieldstone(creek rock /sandstone) interior fireplace chimney. I have lived here 15 years with the house and chimney being 25 years old and from almost day one I have had issues with the chimney leaking. Usually about every two years I will start to get leaking and I go up on the roof and recoat the stone with a aggregate concrete sealer and caulk around the perimeter and between the 3 tab shingle slots whereever there is a crack etc. And this usually stops it for awhile. It usally leaks in either or both of the front corners on the interior where the chimney goes through the ceiling. Well after 25 years I got a new three dimensional shingled roof and I stressed to the roofing company about my constant battle with the chimney leaking. Well they put Ice and Water guard all around and either reflashed or recaulked all the old flashing etc to the point I was satisfied. Well after two months the chimney is leaking again in the same old front corner. I feel it is not leaking through the stone with all the sealer I have put on. The crown looks good with no cracks. The counter flashing is(I think) stainless steel and I really think they did a good job. However, there is no cricket and the chimney is about 5 ft. wide with about 10 ft. of roof above it. I don't know. They are coming out today or tomorrow and I am going to tell them either a cricket or fix it with shingles or flashing and no tar or geocel caulk. I probably have rotted rafters although I think the plywood was good except for each front corner. Anybody got any sad stories about perpetual stone chimney leaks or advice to help me finally whip my problem. I have heard stone chimneys are the worst for leaks and thru flashing all the way to the flue as you are building them is the only sure way to stop leaks. I don't know. Thanks for any solice or advice. Tony

 

[TKeller]

That is not a bad idea as one of my perplexions has always been is the leaking from the stone or the roof. To this day I haven't been sure. Although the present leak is roofing related as I can put a garden hose above the chimney and run it down to the back and the leak will start after awhile. I don't know how hard to push a cricket as they will have to take up some of the new shingles to tie the little valleys into and new flashing has to be cut into the irregular stone. Another procedure that has to be done perfect. A cricket into the chimney now is a skilled job that I think they could do but probably don't want to do even if I pay for it(which I would) since it wasn't in the original scope of the job. If things get too back and forth a tarp over the chimney is not out of the question even though it is a pretty big chimney. Thanks for your comments. Tony

 

[TKeller]

The cathedral ceiling was done with rafters and they were undersized with over a 20 ft. span. There is some sag on either side away from the chimney. The chimney was built first class however with a concrete blocks going through the floor in the crawlspace with a footer. So any movement would be the roof. And there has been some. That is why, I think, you have to depend on the chimney flashing and counterflashing for leak protection and not tar and caulk. For some reason, roofing companies when they reroof a house they want to do as little reflashing as possible. A famous trick around here is to use the peel and stick and wrap it around the existing counterflashing. But I agree the garden hose test shows their work is causing the leak. Although, there still could be other issues adding to it. For ex. with the stone or flashing in the front or sides of chimney. Shheeeeeeshhhhh. Being a home owner. Tony

 

[summit]

how deep are the mortar joints to the stone chimney face, over/under 2"? if under, you may be able to scribe a channel in the masonry about 8 -10" above roofline with a skill saw or grinder w/ a diamond blade. make this channel all around the chimney on the same line. from there you will need a metal shop to make you up a stainless or aluminum rigid flashing to tuck into said scribe joint and "L" out to tuck under the roofing. you could probably even lay in some lead if it was wide enough or if you give the standard 8" wide lead enough overlap on the vertical seams. but a two pieced boot of alum or Stainless Steel should be better. allow for an edge to rivet the two half sections together and apply a sealant to the vertical seams where they meet.