Hey Everyone,

I am new to this forum and I wanted to post my situation to see if I could get some insight. I recently had a contractor come out to my house to inspect a few things. When we went into my crawl space he had suggested I install a vapor barrier because of the dampness in the crawl space. Here is a background of my specific situation:
1) The home is located in Basye, VA 22810. We have hot humid summers up to 100 degrees, and 0 degree winters with wind.
2) It is built on a mountain side that is rather steep
3) The crawl space is triangular in shape. When you walk in the ceilings are about 15-20 feet high, and at the furthest point the crawl space floor reaches the bottom of the house (walk out basement is over the crawl space...remember, this house is on a steep hillside)
4) The crawl space is huge and is not heated
5) Crawl space vents have been stuffed with insulation by previous owner
6) The ceiling in the crawl space has been poorly insulated by R-11 fiberglass. Above the ceiling in the crawl space are 2 bedrooms, 2 bathrooms, and a basement common area.
7) The interior of the crawl space is actual rock ledge that juts into the room (I think it was blasted when originally building the home). The floor is just loose dirt/rocks naturally occuring in the area.
8) The walls are cinderblock with no current protection/insulation outside or inside.

I have not noticed any mold on the joists or water droplets on the crappy insulation. However, the crawl space is very humid feeling and musty smelling. I also noticed that the basement above even has a smell occassionally. My question is regarding what is the proper thing to do for this type of situation. My 2 objectives are to insulate the basement of the house from the freezing cold crawl space in the winter, and to also protect the foundation of the house from any moisture. Any help is greatly appreciated!!

-Ben

 

Welcome to the forums Ben!

I'd be inclined to open up the foundation vents which will help remove the moisture and better insulate the floors ..... but I'm not an expert in this field although we do have some members that are - they'll likely post replies later.

 

Thanks for the welcome! My initial thought was to replace the poor insulation in the ceiling of the crawl space and to put a vapor barrier over the exposed hillside. From what I've read online, it seems that keeping the vents closed in the summer will actually reduce humidity in the crawl space. But given my unique situation of having both hot, cold, and wet conditions I was not sure. Hopefully some experts will chime in

 

It's been my understanding that you either have to have working vents or seal off the entire crawlspace and add HVAC vents or maybe run a dehumidifier. Adding a vapor barrier doesn't hurt.

 

Yep, crawlspaces are either open to the outside and sealed from the house (with insulation in the ceiling and not on the walls) or open to the house and sealed from the outside (with the insulation then on the walls and not the ceiling).

I think I'd go with Mark's plan as well based on what I'm understanding of your situation.

 

Thanks for the responses. I guess I should have include this one other part about my crawl space and house. I do not have central heat or AC. I have baseboard heat and a window AC unit in the top floor of the house. So there is no duct work in the house for me to run a vent down to the crawl space to heat or cool it.

However, the kicker is that I do have some water lines that run through the top part of the crawl space (the joists of the basement). My main plumbing stack for the house also comes right through the foundation of the home and vertically up through the crawl space and up into the house. The plumbing stack is completely enclosed in an area the size of a closet. It has rigid foam insulation on the cinderblock walls in this area as well as a base board heater to help keep the pipes from freezing.

So in the winter I was not particular inclined to re-open the crawl space vents to let in any colder air than I had to.

 

I have a vented crawlspace under my house. I routinely close the vents during the winter but open them back up when it warms up. All your water supply pipes should be insulated. You can use heat tape on them if insulation alone isn't enough.