Hi: Bought a second home in Florida three months ago, been living in it while doing the renovations, never had a plumbing issue until today: I use one of the tubs to take a shower, during which the water today obviously wasn't draining. It stayed clogged for ten minutes and then from another room I could hear it let loose all at once. There's a linen closet that backs up to the tub, it had some failed shelving and crude access panel in it for this tub, so I decided to neaten things up today and took out the shelving , infilled the approximate 1'x2' access panel with drywall, and gave it a coat of mud. Is it possible that infilling the access panel with drywall somehow impacted air pressure in the drain/vent causing the tub drain to clog? I found it ironic that I've used this shower for months with no issue until today.