Mysterious Crawlspace

[Curtis Hildebrand]

I was inspecting a crawlspace yesterday which was one of the best crawlspaces I've ever been in. It was 3 feet high with insulated walls. The humidity ranged around the 50% mark. There were no moisture stains of any kind. It had a functioning dehumidifier. Strangely enough, though, this crawlspace smelled very musty and this smell permeated through the entire home. The only potential issues I found causing this was no ventilation, damaged stucco throughout the exterior and no sump pump (they had a drain which drained water out of the pit to the town sewer line). Has anyone found a similar crawlspace with no apparent source of odor?

[James H. Bushart]

Originally Posted by childebrand

I was inspecting a crawlspace yesterday which was one of the best crawlspaces I've ever been in. It was 3 feet high with insulated walls. The humidity ranged around the 50% mark. There were no moisture stains of any kind. It had a functioning dehumidifier. Strangely enough, though, this crawlspace smelled very musty and this smell permeated through the entire home. The only potential issues I found causing this was no ventilation, damaged stucco throughout the exterior and no sump pump (they had a drain which drained water out of the pit to the town sewer line). Has anyone found a similar crawlspace with no apparent source of odor?

Describe the vapor barrier.

[Curtis Hildebrand]

The floor was concrete with no vapour barrier. The walls were Logix (permanent styro forms on both sides). Half the walls had interior vapour barrier and half did not. There was no barrier at the floor joists.

[James E. Braun, CMI]

Where is the ductwork ran?

[Christopher Currins]

they had a drain which drained water out of the pit to the town sewer line

Did it have a p-trap?

[Jeffrey R. Jonas]

Originally Posted by ccurrins

Did it have a p-trap?

And what is keeping the trap primed?

[Curtis Hildebrand]

There was no P-trap. The pipe was just a straight pipe running into the concrete. I couldn't see much of it. There was no sewer smell, just a musty, mold-like odor.

[James Khan]

Hmm, seems like a tough one to pinpoint the source of the smell. Interested to see what others think.

James Khan
Inspection Software - Infomation Portal

[Jeff Zehnder]

This sounds suspiciously like a closed and possibly conditioned crawlspace. If the side walls are insulated (even with leaving the band un-insulated) and the slab is insulated it is possible. Normally the band would be insulated and a 3-6 inch strip at the top of the block is left uncovered for termite inspections. There should also be a supply duct and a return cut into the floor somewhere. Your photos do not show enough of the crawlspace to be sure.