Latest Discussions : Basement & Foundation


08:32AM | 03/31/05
Member Since: 03/30/05
4 lifetime posts
Can anyone give me some advice on whether or not a vapor barrier is necessary when waterproofing a crawl space? I've had two waterproofing companies (and two more to go)give me an estimate. Both suggest the pipe & tile method w/ a sump pump to pump out water. However, one contractor also suggests a vapor barrier and the other doesn't. The one who doesn't says that you will always have condensation (ie moisture) in the crawlspace even if there is a vapor barrier, so it is not necessary as long as the system is working and keeping the water from standing. I'd like to say no to the vapor barrier to save money, but I don't want to cut a corner that will hurt me in the long run. Any help would be appreciated!


11:04AM | 03/31/05
Member Since: 06/23/04
161 lifetime posts
Mold and mildew need three things to survive - a food source, water, and proper temperature. The food can be any organic material. The water can be any type with humid air being the best. Temperature is best when between cool and cold. Enemies of mold and mildew are high temperatures, sunlight, and dry air.

If you have water in the crawlspace, the best solution is to stop it from entering in the first place. That is the only way for the soil to dry out and prevent other problems such as rotting, mold, mildew, etc. Often, this solution is not inexpensive. You don't need a vapor barrier if you can keep the crawlspace dry.

As a last resort, collect and pipe the water away. Keep in mind that the crawlspace will remain damp and create opportunities for mold and mildew growth. A vapor barrier can be helpful here in that it will retard the evaporation rate of moisture from the soil and keep the air more dry . However, the vapor barrier has a two edged sword. It also creates surfaces with high moisture concentrations between the plastic and the ground that can be a breeding ground for mold and mildew.

Crawlspaces should always be ventilated to help remove moisture. This is true even in the winter. Don't block your vents in winter.


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