Musty Smell in ONE room of new home (after pressure washing)

7 years ago

Hello everyone -

I purchased a new home (south florida) a few months ago that was built in 2003, with a 1,200 sq ft addition built in 2004. The house is stucco over concrete block with a tile roof. The interior is drywall with a thin layer of vapor barrier between the drywall and concrete block.

About 3 months ago, I had my house pressure washed. After the pressure washing, I noticed that two rooms of the ADDITION developed a musty smell. I ended up opening some drywall in the "office" room, and discovered that the concrete block behind the vapor barrier was wet. I opened two 20x20 sections in the wall and used a large air mover for about a week to get the walls dried out. The smell in that room has subsided, although the smell of wet concrete still lingers if you smell inside the holes of the drywall.

The other room, call it the game-room, still maintains a persistent foresty-musty-damp/earthy odor. I've cut a 20x20 hole in the wall above a window, but there is no smell in the wall and no signs of dampness. I have an industrial air mover going along with the ceiling fan. The A/C system is brand new, and humidity in the room never goes above 57%, but tends to stay around 54%. The smell sometimes gets much stronger, and other times it goes away completely. I've had the smell when it's wet or dry outside, as well as when it's cold or hot. It seems temperatures don't really matter to it.

Some background on the addition.

There was a mold problem in one of the OTHER rooms (that has no smell). We remediated correctly, 2 ft of drywall, negative air, air scrubbers, hepa vacs, concrobium, etc. Mold air tests showed extremely low mold counts, lower than the "low" spectrum of new homes, with a ZERO reading of toxic molds. The two rooms with the odor were not infected with mold at any time.

Doors/windows of this addition had never been properly sealed. Water had entered through the window frames on several occasions before we took ownership. All windows have been sealed since.

The attic is fine, with no unusual odors or signs of moisture intrusion.

The floor is a concrete slab with tile on top of it (original construction).

The drywall is american made, and the room has been freshly painted with 2 coats of Behr and 1 coat of Killz primer.

I've had several different opinions from several different GC's ranging from trenching and sealing the concrete walls to the foundation, demo'ing the tile floor + sealing the slab + re-tiling, or even demo'ing all of the drywall and investigating the concrete block.

I'm at my wits end - as I've been trying to find out the source of this smell for almost 3 months. I find it strange that the smell would start immediately after pressure washing, but by the same token it's been 3 months and it should have dried out by now (assuming water got in through a stucco crack or something).

If anyone has some suggestions on what I could do to get rid of this "basement" smell from this room, I would greatly appreciate it.

Comments (17)