I want to remove a chimney and close up the hole. The chimney is brick, about 17 inch by 17 inch and located right next to the ridge board. The roof is 9/12 slope, tar shingles in good shape. Demolishing the chimney itself and patching up the sheathing is straight forward for me but I'm not clear how to best waterproof and shingle over the patched hole.

The ridge is vented. The vents are Certainteed's plastic filtered vents or similar. The opening is cut to within 6 inches or a foot from either side of the chimney but the actual plastic vent comes within 2-3 inches of the chimney. The lead counter flashing is cut a bit long and extends out from the chimney by a few inches. It's actually caulked to the shingles underneath. The very end of the ridge vent sits on top of the lead. Here is a sketch of the layout:

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The ridge vent is closed from the inside and no longer needs to be there so blocking any amount of it is not a problem. Having a section of closed ridge between the 2 vented sections is fine. Realistically, the whole thing should be converted to closed ridge but that's too much for me.

I understand how closed and vented ridges go together but it isn't clear to me how much needs to be taken apart here and how to fill it in to be waterproof. I take out the chimney, pull out the partial shingles and lead around the hole, patch the sheathing, throw some membrane or underlayment over it and shingle over the whole thing again. But how do I weave it all in with the old shingles, ridge caps, and vents? Can the vents be partially pried up then nailed back down?

1 Answer 1


You just remove all the partial shingles related to the chimney, and continue with the existing pattern of the other roof shingles. You could fill in the area between the ridge vents with a couple layers of 1/2" plywood, then apply cap shingles over that and lapped over the existing ones on the vents.

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