Originally Posted by PonderosaMax
I opened up one of the drawers in the bathroom vanity on a particularly windy day and noticed there was a stiff breeze coming through. Opening the cabinet, it's clear the breeze is coming through the access hole for the the drain and water lines. It feels like there is direct access to the outside world.
I stuck a flashlight in the hole and crawled around underneath but never saw an opening. I could just stick some insulation in the hole but I'd rather determine the source of the problem. What should I be looking for? This summer breeze is NOT making me feel fine.
The breeze could be coming from any place the water lines/drain lines access the outside, like the wet bay for example. Clearly, you cannot see the route of your plumbing lines from underneath but they obviously run under the interior floor to some extent. Like water leaking through a roof, where it appears on the inside is not necessarily where it enters from the outside.
If this was my issue, I'd simply put insulation in the hole of the cabinet where the plumbing passes through and forget about it.