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Rick, General Contractor
Category: Home Improvement
Satisfied Customers: 21775
Experience:  Licensed construction supervisor with 35+ yrs. experience.
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My home has a well maintained crawl space with a plastic

Customer Question

My home has a well maintained crawl space with a plastic moisture barrier over the earth floor, and has fiberglass insulation in the floor joists.
I would like to use the crawlspace to do 2 things, extra storage (particularly for lawn equipment) and as a homebrew beer workshop. To this end, I would like to install plastic sheeting on the bottom of the floor joists (to create a sanitary barrier/ceiling), and install a hard-surface floor to store equipment without damaging the plastic vapor barrier.
I am concerned about the effects this will have on moisture retention on above the moisture barrier and in the floor joists. Can anyone provide any advice on ways to accomplish my goals?
Submitted: 10 months ago.
Category: Home Improvement
Expert:  Rick replied 10 months ago.

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

If you're installing a floor in the space concrete over the plastic vapor barrier would be best. In this case you shouldn't need/don't want another vapor barrier on the bottom of the floor joists. You could use plywood on the bottom of the joists.

Customer: replied 10 months ago.
What about a removable flooring of some type to cover just part of the floor? And as far as plywood under the joists, can I use plastic sheeting instead, I want to prevent moisture from penetrating the plywood.
Expert:  Rick replied 10 months ago.

You can't put anything on the floor that won't destroy (poke a lot of holes in) the plastic. Only concrete will give you a good hard surface and protect the vapor barrier. With a vapor barrier on the floor you don't need one on the ceiling and would be better off without one which could trap moisture in the joist space. You could use a product like Tyvek which would allow water vapor to pass through it.