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Community and Q&A

Exterior Drain Mat Installation

tundracycle | Posted in General Questions on

This is related to the problem of moisture in our wine room:

When they did the waterproofing for the cap of our front stoop (ceiling of wine room) they removed the top 3′ of drain mat (1st photo). They then re-installed this used/older drain mat that had been laying in the dirt for a while and was also somewhat damaged (as was the top of the mat that was still attached). There are a few concerns with this;

– The mat would already have had cured mastic on it so would not adhere to the mastic on the walls.
– I believe they did not re-apply mastic but attached the old mat mechanically only so there would effectively be an unsealed gap between the drain mat and the wall for water to collect in or run down.
– The bottom of the re-applied mat and the top of the still attached mat were not uniform or clean. They were damaged, irregular and had dirt on them.

My understanding is that they when re-doing it they should have cut off the top of the old mat to get a clean and uniform edge, applied new, clean, undamaged mat using the original sealing mastic and mating up tight against the lower mat.

This seems like it could all result in considerable potential for moisture to enter? Or not really?

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