moist crawl space
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 read about two alternative approaches to dry out the crawl space:
a) Use a dehumidifier such as the Dri-Crawl Space Dehumidifier
b) Open up a HVAC duct and an air return to dry and warm the crawl space through conditioned air. This will also reduce overall heating/cooling cost since it the air from the crawl space will have a similar temperature as in the floor above.
- 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?
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. What is the best material to seal the crawl space. In one article, Tim Carter (author of 'Ask the Builder' column) referred to high performance polyethylene as the best product. Other sites are recommending higher end products such as the 'Crawl Space Vapor Barrier,' which is made of 7 layers. 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.
Any help would be greatly appreciated.