Vapor Barrier Under Cement Slab

Too much moisture in concrete is a problem because it can cause ph changes that destroy adhesives.

Vapor barrier under cement slab.

Should you put a vapor barrier under concrete slabs. Thin plastic like this is often called a vapor retarder meaning it slows the vapor down but doesn t stop it. Why is too much moisture in concrete a problem. Meadows vapor barrier is called perminator it also comes in 10 mil and.

By reducing the moisture gradient and diffusion in your slab you can virtually eliminate efflorescence caused by under slab water vapor migration. Astm e 1643 standard practice for installation of vapor retarders used in contact with earth or granular fill under concrete slabs provides details but here are a few tips. To be effective a vapor barrier must be installed in a way that prevents any water vapor from getting to the slab. Chemical resistance consideration if a vapor barrier is being used under a slab to control vapors at a brownfields site the chemical resistance of the vapor barrier must be considered.

Meadows that make equivalent vapor barriers to stego wrap. 2 4 how to install vapor barrier on concrete floor under laminate flooring. If heavy equipment will be operating on the vapor barrier or if the vapor barrier will be installed over an angular subbase a minimum of 15 mils is recommended. Vapor barriers under concrete floor slabs.

Why and how is there moisture in concrete slabs. A much better approach is a true vapor barrier with characteristics that conform to the requirements of astm e 1745 standard specification for water vapor retarders used in contact with soil or granular fill under concrete slabs. Reinforcing has to be supported so that it is in the top 1 2 to 1 3 of the depth of the slab throughout the pour. In the past i ve used 6 mil poly as a vapor barrier under concrete floors and slabs and will say it is easily punctured the stego wrap is much more puncture resistant.

There needs to be a vapor retarder at least 6 mil between the base course and the slab. Astm international gives specific guidelines in astm e1745 17 and astm e1643 for the use installation and inspection of vapor barriers used under concrete slabs. Months or years from now the water table link might rise and the water will pass through concrete in water vapors with a. A high performance vapor barrier once again can eliminate one of the variables which leads to the condition in the first place.

Find out where to buy vapor barriers and other problem solving products. There is always water underneath the ground while it might not be near the surface it is there. Its not required for accessory structure storage rooms under 70 sf flatwork that isn t enclosed and other approved site conditions.