We have a 12'x15' crawlspace underneath a den in our house adjacent to the LR that my wife wants to turn into a homeschooling room for the kids instead of doing it at the dining room table. It will work better to have a formal space with desks and it's already got a nice built-in for all their books and stuff.

The problem is, this is dirt floor crawlspace and lots of air intrusions from the outside wall and patio, it's cold as hell in that room in the winter. You can sit on the hardwood floor and actually feel the cold air coming up and in. In the summer the basement is always musty and the poor dehumidifier runs 24/7 and can only ever get to maybe 60-65% because I may as well have windows open with this dirt floor.

I had a guy come from a large and well-known (and well-reviewed) basement waterproofing company that also does crawlspace encapsulation come and look at it and give me a price quote on doing it.

They will:

-Seal all air intrusions
-Close off all vents
-Foam board the walls with 2" thick silver foamboard
-Grade the floor
-Place a matting down then a 20 Mil thick vapor barrier material that goes up the walls a bit as well
-Install a sump pump in the space
-Install a dehumidifier in the space

Total was about $5,000

Does that look right? We really need to address this as the room is basically unusable in the winter and I'm sure it's affecting my heating bill

This is what they will do, right now I have a nasty dirt floor with all sorts of debris, someone put fiberglass insulation batting in the joists at some point to try and "fix" the issue and the previous owner had a large electric baseboard heat strip installed above because I think it was his TV room and he was cold:

(example from their website):




I'm just trying to see if this sounds like a fair price or if I could do better. I know the company does good work and has lots of good reviews on Yelp, Google etc

That doesn't seem out of line to me. You may well amortize the cost in fuel savings in a few years.

quote:

Originally posted by PASig:
We have a 12'x15' crawlspace underneath a den in our house ...

Our's is 13x22.

quote:

Originally posted by PASig:
The problem is, this is dirt floor crawlspace and lots of air intrusions from the outside wall ...

Same. As well as the id10t original owner of the home, who never did one damn thing correctly, put the sill atop hollow cinder blocks.

quote:

Originally posted by PASig:
I had a guy come from a large and well-known (and well-reviewed) basement waterproofing company ...

I'm thinking of doing the same. We had it done by professionals once, already, and they didn't do a very good job.

quote:

Originally posted by PASig:
... right now I have a nasty dirt floor with all sorts of debris, someone put fiberglass insulation batting in the joists at some point to try and "fix" the issue ...

That's what we had. Worse: The original owner put in backed insulation and had it facing the wrong way

The "pros" we hired to fix all that took all that out, cleaned up the dirt floor, put a vapor barrier down, and put fiberglass batts up against the outside walls.

Some of those fiberglass batts have since fallen down.

quote:

Originally posted by PASig:
(example from their website):

That's what I want.

We don't need a sump pump or dehumidifier in our space, though. Even with all the st00pid the original owner did, moisture wasn't a problem.

And, right after I get all that cleaned up, I may take the opportunity to get in there and run some Ethernet cabling into one of the baseboards--right behind the home theater stuff

quote:

Originally posted by ensigmatic:


The "pros" we hired to fix all that took all that out, cleaned up the dirt floor, put a vapor barrier down, and put fiberglass batts up against the outside walls.

Some of those fiberglass batts have since fallen down.

I'd say 1/3 of the batts in the joists in my crawlspace have fallen down or are hanging. The guy told me it's because they soak up moisture and eventually fall down from the weight.

quote:

Originally posted by PASig:
I'd say 1/3 of the batts in the joists in my crawlspace have fallen down or are hanging. The guy told me it's because they soak up moisture and eventually fall down from the weight.

No doubt.

Ours were all still in place because whomever put them up there at least ran supports across the bottoms of the floor joists to keep them there.

Still the wrong thing to do.

Fiberglass batting is no longer recommended for rim joists and other areas subject to moisture for the reason that it can retain moisture, thus becoming less efficient and becoming a place for mold to grow.

Our job, when I get it re-done correctly, will probably be more expensive than yours. Or at least as expensive. Larger area and, while we won't need the dehumidifier or sump pump, it will be very laborious to seal up the entire rim due to the incorrect construction.

Fracking id10t original owner

$5K doesn't sound bad, probably help with energy bills too

I am/was a Class A contractor specializing in highly efficient custom homes. I also just bought home in Pinehurst, NC with an open crawl space that I am in the process of converting into a conditioned crawl space.

My foundation space is about 2000 SF. I started off by cutting out some foam board to seal the foundation vents.
Then I went to Lowe’s and bought some 2”, R-10 foam boards that I am attaching to the interior of the foundation walls with 3” roofing nails and styrofoam adhesive.
I had a local HVAC company come over and install a 6” adjustable damper about midpoint in the main trunk supply line.
I already had a 10 mil vapor barrier so I didn’t need to touch that. I will not need a sump pump and even though it has a dehumidifier down there I may not need it once completed.

My total cost will be less than $500 but it does take some labor.. Depending on where you live and what your surrounding soil is that may be all you need.

For a room as small as yours $5000 does seem a bit on the high side but I don’t know about prices where you live. It will save you money and make your living area more comfortable.