When there is a water supply line leak behind or under a shower or tub, it might be possible to
dry affected drywall and framing from the other side of the tile or fiberglass surround by coming
in from behind or under it. Remember, to dry wet materials, we just need to provide hot, dry air
to the water and be able to confirm the wet materials are left in a state that won’t promote
microbial growth. If the supply line leak is in an exterior wall, it may be necessary to open the
surround if we can’t get air to that area from either side of the surround. Most times, if the leak
is in the exterior wall behind the surround, the plumber will have to open it up to repair the leak.

‍

First, identify if there is access to where the water loss originated from an adjacent interior wall
so we don’t have to remove the surround. Many times, the supply lines are in an interior wall
we can access from an adjacent room. Then, open a small inspection port at the bottom of the
wall since moisture will migrate to the bottom of the wall cavity due to gravity.

‍

Once we identify what is wet, we can duct hot, dry air from our dehumidifier into the wall, while
taking daily penetrating moisture meter readings inside the wall with a moisture probe attachment.
See photo below for how to access under a tub surround. If removing one tile, be sure to not
crack the tile so it can be reinstalled.

If you are in a state where there are shear walls on the adjacent wall, you will need to consult
your local building codes before drilling holes in shear walls. I always tell restorers we can get
hot, dry air into very small holes, and the hardest part might be obtaining good photos of our
final moisture content readings to ensure we reached our dry targets. It will be much easier and
less expensive to repair drywall instead of a shower or tub surround. The photos above are from
a previous home I lived in in Texas, where I needed to access under my ceramic tile tub surround
to dry under my tub. I simply cut a one-foot square of drywall out of the adjacent bedroom wall
and once dry installed a simple plastic cover so it would be possible to access under the tub for
any future repairs. I was also able to remove one tile to access where the water line needed to
be repaired and reinstalled with matching grout.

‍