Bathroom Remodel – Voids in Slab
When remodeling or constructing a bathroom or any other room that plumbing or other slab penetrations are present, the conditions should be reviewed during the demolition / construction process and corrected. These conditions include: voids in slabs, moisture damaged floors and walls, leaking shower pan, toilet, sink, cracks, expansion joints, empty conduits, holes.
Most homes in south Florida are built with open slabs or “block-outs” where the plumbing enters from the ground as this would allow for adjustment when the walls, fixtures, i.e., tub and drains are installed. But in many older homes, and unfortunately some newer homes these block-outs were not filled in when completed. This is not a good condition for many reasons, particularly moisture and the critters that come in through these voids such as subterranean termites, water bugs, rats, etc…
Figure 1 – Signs of Subterranean Termite Infestation
Slab Opening’s – If an opening, crack, void, empty conduit or any other penetration is found in the slab:
- Clean area of debris
- Treat with pesticide for, but not limited to, subterranean termites
- Install vapor retardant (this is plastic that is installed prior to slab on grade) when opening is large
- Wrap drain or other metal penetrations with plastic, or penetration seal ring and seal top to pipe
- Fill all openings with concrete or other high strength grout or elastomeric (Caulk) when smaller
- After curing check for cracks and voids and fill with elastomeric caulking to seal.