Painted Crawlspace

[Lon Henderson]

Found a painted crawlspace yesterday. I suspect it was sprayed with a stain killer like Kilz. The house was built in 1996. The crawlspace is a subfloor space under the basement pier and beam floor. The sub floor ventilation system wasn't working and the two steel support posts were heavily rusted (and one had rotated well out of plumb) but my question was why did someone spray paint this space? There wasn't any evidence of a past fire and smoke.

[Jim Luttrall]

Found a painted crawlspace yesterday. I suspect it was sprayed with a stain killer like Kilz. The house was built in 1996. The crawlspace is a subfloor space under the basement pier and beam floor. The sub floor ventilation system wasn't working and the two steel support posts were heavily rusted (and one had rotated well out of plumb) but my question was why did someone spray paint this space? There wasn't any evidence of a past fire and smoke.

The were probably trying to hide mold.

[John Kogel]

Besides hiding stains, the paint actually will help to keep the OSB dry by sealing the surface.
They've laid down a heavy duty vapor barrier.
It is all good, IMO.

The screw jacks, not so good.

[Trent Tarter]

The white paint (Kilz) was most likely used to treat and/or seal fungi growth. I have found that OSB products develop fungi growth more easily than plywood or standard dimensional lumber. It's common for building materials to get rained on, or get damp at the job site. In most cases the fungi growth develops after installation and goes unnoticed by the builder.

[Lon Henderson]

I wondered about mold too, but couldn't find evidence of that. Of course, light mold can be hidden with Kilz. Sealing it to help keep it dry isn't something that I've heard of, but that may be the plausible answer.

[Ken Rowe]

Typically there are only two reasons for spraying wood building products. Sealing mold, or sealing smoke damage.

[Ken Amelin]

The screw jacks, not so good.

Why not?

We hear this all the time. I can see that a hollow steel column with screw adjustment can have a fire protection (rating) issue, but what is wrong with this screw jack as a support column??

Where in the code does it say that you can't use columns with screw adjustments as long they are in accordance with ASTM A 53 grade B or approved equivalent?

[Ken Amelin]

Typically there are only two reasons for spraying wood building products. Sealing mold, or sealing smoke damage.

Thay may be so, but I believe the best way to report on painted wood in crawlspaces or attics is to advise that the structure was painted, the paint may conceal potential underlying problems that were not visible at time of inspection and that the buyer should question the owner about the history of the paint for information, record and further action, as necessary.

[Lon Henderson]

Typically there are only two reasons for spraying wood building products. Sealing mold, or sealing smoke damage.

I agree.

[John Kogel]

Why not?

We hear this all the time. I can see that a hollow steel column with screw adjustment can have a fire protection (rating) issue, but what is wrong with this screw jack as a support column??

Where in the code does it say that you can't use columns with screw adjustments as long they are in accordance with ASTM A 53 grade B or approved equivalent?Take a look at that one jack. It is rusted to the point where it could just collapse. That is what I meant by not good.

[Rich Goeken]

Take a look at that one jack. It is rusted to the point where it could just collapse. That is what I meant by not good.

Looking at the paint (looks like mold abatement spraying), and the damage to the jack (that jack should last for years without rust) looks like a high water mark or water was spraying on it for a while----the basement was flooded and mold took over.

[Matt Fellman]

Is under floor insulation required in your area? It's been required here since the early 90s. That could add fuel to the "space being flooded" theory.

[Lon Henderson]

Is under floor insulation required in your area? It's been required here since the early 90s. That could add fuel to the "space being flooded" theory.

No, I've never seen a basement under-floor crawlspace with insulation. Ordinary crawlspaces (under the house floor) frequently have the foundation walls insulated or insulation in the floor joists. In this house, the foundation walls are insulated but none in the crawlspace.

Obviously, someone really wanted this sprayed, because it was a pain in the arse crawling through that space with a spray hose. I looked for evidence of heavy mold but didn't see any. Light mold is easily covered by Kilz, but you can often see the evidence of heavy mold even through the Kilz.

After considering the comments here, I wonder if there was a flood in the past (the rusted steel posts) and someone decided to spray Kilz as a preventive or to seal light mold. There are two sump pits and pumps (one is the normal). Both are about 3' deep and dry, but we are in an extended drought. In a wet year, the water table could be considerably higher.

Incidentally, we have active soils here with expansive clays. When houses are built, if the soil samples show low levels of expansive clay, then the basement usually has a concrete slab floor. But if the samples show high levels of expansive clay, then they put in the more expensive pier and beam basement floor with a shallow crawlspace. Many times I can't get into these tight crawlspaces. In the newest homes, they're sealing the dirt floors of these crawlspaces with plastic sheathing and treating them like part of the conditioned spaces. In 1996, they didn't do that and this crawlspace has been retrofitted with the plastic sealed vapor barrier.

[Sam Morris]

Most likely from a mold/fungus remediation