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Charles
Charles, Engineering Contractor
Category: Home Improvement
Satisfied Customers: 2066
Experience:  20+ years in most phases of construction
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This is a roofing question, but a HVAC or plumber might know.

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This is a roofing question, but a HVAC or plumber might know. I installed a concentric vent on the roof for a condensing tankless water heater. It comes with a plastic flashing that is supposed to insert under the high side shingles. Unfortunately I have roll shingles (that look like regular). The vent is fairly close to the crest which has a couple of inches of overlap. For now used a lot of Henry's Roofing Compound under and over the sides of the black plastic flashing. Can I just use a lot of compound and cover the roofing screws etc.? Or do I have to use metal flashing and extend up to the crest? It must be up to code for the water heater Building Inspection. Later there'll be a inspection for a new furnace and it will have a flue much closer to the edge of the roof. So maybe the same problem will reoccur.

I won't checking my computer until around 8:00AM Sunday. So don't need an answer tonight.

Charles :

Hello, and thanks for your question! My name is XXXXX XXXXX I am happy to assist you today!!

Charles :

Yes, you can do it that way as long as it is temporary

Charles :

Withing a few months the henrys will start cracking

Charles :

A better product would be Henrys White Elostomeric patch and coating, when you apply it you should apply a layer of nylon webbing to prevent it from cracking.

Charles :

The way you do it is to apply a layer of the patch compound, then the webbing, then another layer of patching compound.

Charles :

This method will last for a few years

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