Hi,

My crawl space is moist, i.e., the air is damp and the foundation walls show signs of wetness. A mold inspector has not found mold and the subfloor is dry. I am planning to dry out the crawl space and I have a few questions regarding your product and the various approaches that I've read about:
1. I've come to your site via 'Ask the Builder' where you or one of your colleagues pointed to the Crawl Space Vapor Barrier product. (Very nice site, btw.) In the article, Tim Carter (author of 'Ask the Builder' column) referred to high performance polyethylene. Can you tell me what the advantage of the Crawl Space Vapor Barrier over the high performance polyethylene is? I'm not planning to use the crawl space for storage.
2. Based on what I read, the best practice indicates that one should close the crawl space vents and to seal the crawl space. But given that moisture will still be underneath the vapor barrier, will this not lead to wet foundation walls and wet studs underneath the vapor barrier?
3. I've read about two alternative approaches to dry out the crawl space:
a) use a dehumidifier
b) open up a HVAC duct and an air return to dry and warm the crawl space through conditioned air.
- Is option (b) the cheaper solution that is recommended for less moist crawl spaces. Is option (a) recommended for severe cases? We live in Maryland (West of DC), so it gets humid in the Summer, but it's not as wet as in the Eastern Shore.
- Does option (b) require insulation of the foundation walls, while option
(a) does not?

Any help would be greatly appreciated.

Many thanks,

****** (customer asked to remove his name)