Just bought a house with a crawl space. No vapor barrier, floor insulation or foundation venting. The crawlspace is moist. There are some grading issues to be addressed. I intend to put down plastic and insulate the floor. Adding vents thru the poured foundation will be difficult. Is venting the space thru a stud cavity (metal ductwork) straight up thru the roof a viable option?
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Replies
I think you'll find that laying down a layer of 6 mil poly will help immensely...try to find some that has nylon re-inforcing fibers embedded, it's alot tougher.
i have nothing to contribute to the crawlspace conversation, but happened to go to your site.
holy crud!!!!!!!!!! your work is awesome. do you come to nj?
Thanks for the kind words. We don't travel too far from home - so far there's plenty of work nearby. I do fabricate and ship, though.Birth, school, work, death.....................
http://grantlogan.net/
Cut in a couple of vents in the foundation, install a small fan on a timer to kick air out. As it is kicked out one opening, the other opening - hopefully in a different area - will pull ihn fresh air.
Advocate
I disagree. Seal it up and condition it. Treat it like a really short basement.
Put poly on the floor, insulate the walls, and run a heat run down there. You'll have warmer floors, no worries of pipes freezing, and you wont be introducing moisture to the area.
I think the appropriate solution has a lot to do with climate. I'm out on the west coast, so we don't worry about outside air bringing in moisture. We do worry about foundation walls being covered in a way that can obscure termite tubes, and the B.I.s don't allow conditioned crawlspaces.
I think the original poster was in Kentucky, a climate I'm not educated about.
Advocate
I dont know much about the west coast. Do you have to vent basements out there? I dont mean to sound sarcastic but, its kind of logical not to vent. You then have control over what comes into the space.
I understand what you're saying about termite threat but , once again how do you handle that in a basement situation? Should be able to address it the same way.
In CA we are under the UBC. It has a specific requirement for square inches of CS venting per SF of floor area above. I have not heard of a single example of a conditioned CS on the west coast. I have asked local termite inspectors about this design and none of them will go for it.
Advocate
>>I have asked local termite inspectors about this design and none of them will go for it.Too lazy to lift the FG insulation hanging from the sill plate?
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that had been our 30 year experience. Treat it like a short basement. We insulate the short walls c/w vaporbarrier. 6mil poly on floor and either finished concrete or slurrcoat
If you don't have rigid insulation under the slab, would there be any benefit to putting it on top, or just the poly.
And as far as heating it, if there is an opening (3' x 3') to the rest of the basement, is that sufficient for heat, or would you cut in a register.
I was refering to rigid on the walls. I dont believe you need it on the floor (at least up here in detroit you dont).
You will need an actual heat run for the crawl. The opening wont cut it.
This was a frame house originally with a block foundation. It has a poured foundation outside of the block to carry the brick veneer that was added later. Lots to cut thru to add foundation vents. One side has a concrete driveway that is poured against the house (part of the source of moisture).Birth, school, work, death.....................
http://grantlogan.net/
Why vent?
In the summer you will just be allowing HOT, HUMID air into a cool space and the RH will go way up. Probably enough to grow mold.
House was purchased a couple of years ago. Its been fine for at least 80 years(thats old for the west coast) But the officials made the sellers vent the house. Now pipes are freezing and holes are cut all over the outside. The city inspectors have no clue as to the real world....they are just going "by the book". I think we all know there is no "book" that covers every microclimate.
Re Venting: there is no one solution; it depends on your heating system and your location.
Check out the Building Science Corp's website for the best info on crawlspaces and venting.
In my area (NW Ohio) a conditioned crawl space where there is forced air heat and A/C generally performs much better than a vented crawl.
Thanks, Bob (and others). Radon is a concern in doing that. I haven't tested yet. I get possession tomorrow, so I'll be able to assess the situation better by the weekend.Birth, school, work, death.....................
http://grantlogan.net/