Conditioned Crawl Space Insulation

LuckyFoot15 · 09-21-2012, 04:07 PM

I have a family room addition on the back of our house. It has a concrete crawlspace below it that currently does not have direct access from the basement that it backs up against. Both the family room and crawlspace are conditioned.

The previous owner installed kraft paper faced insulation between the crawlspace and family room. About half the crawlspace has this insulation AND drywall over the top of the insulation. It looks like it may have been unconditioned at one point in time, and it was eventually changed to a conditioned space.

We had a pretty well certified home inspector when we moved in. He recommended, at the very least, taking a knife to all the kraft paper that was exposed, in order to let the insulation breath and not trap moisture. I have not tackled this job yet. When I was down in the crawlspace today, I took a few pictures. I looks like some of the exposed (and covered) insulation may have surface mold starting on it. There is no moisture in the insulation that I inspected, but that doesn't mean that there never was moisture, correct?

With winter coming, I would like to tackle the insulation problem. Can someone tell me if the dirty/grim in the photos is mold? Considering all this space is conditioned, am I best off ripping out all the drywall and insulation that may be improperly installed?

In addition, the first three of the photos show the corner of the crawlspace that I plan to reopen so that the crawlspace can be accessed from the basement. You can see what I found when I pulled off the drywall...

Windows on Wash · 09-21-2012, 05:00 PM

The dirt on the insulation is likely from air movement and not mold.

The mold on the lower area surface insulation is probably due to moisture perking from the concrete. I would make sure that concrete is well sealed with a vapor barrier type coating or put down plastic.

In theory, have a vapor retarder level between conditioned spaces should not make a difference. I would be willing to bet there is still higher than normal humidity levels in the crawlspace.

LuckyFoot15 · 09-25-2012, 03:26 PM

With the recent cold nights, the crawl stays more conditioned than the room above it due to heat and air leak in the ducts. I will probably start pulling down the insulation and drywall and toss it into a pile for repurposing in other parts of the house...maybe just rip off the kraft paper and throw it in the attic.

LuckyFoot15 · 09-30-2012, 01:13 PM

I got around to pulling insulation and drywall out yesterday. It went pretty well, and I found a mouse nest and droppings. I suspect it was the same mouse that our cat fished out and I trapped last year

.

I drilled a hole into the corner that I thought faced the basement...and saw daylight. I forgot that the corner of the house extends out about 4 feet from the original foundation. With this said, I will likely start a new thread about how to properly frame out an access door / header through the wall (like the one in the picture).

I still have some work to do, but when I'm done, the walls will all be insulated and drywalled and the floor will be exposed with no insulation or drywall. I ripped the paper face off all the insulation and added it to the attic.

**Gary in WA** · 09-30-2012, 02:35 PM

"I ripped the paper face off all the insulation and added it to the attic." ------
Good work! Vapor barriers/retarders are area weighed or surface measured, pp.5 - Magnitude of vapor diffusion; http://www.buildingscience.com/docum...researchreport

Gary