Vapor Barrier Under Cement Slab

Why is too much moisture in concrete a problem.

Vapor barrier under cement slab.

Its not required for accessory structure storage rooms under 70 sf flatwork that isn t enclosed and other approved site conditions. Meadows that make equivalent vapor barriers to stego wrap. 2 4 how to install vapor barrier on concrete floor under laminate flooring. By steve ragan director research and technical services the answer to this controversial question from both angles is a qualified yes vapor barriers have been associated with certain concrete slab on grade problems including curling and cracking.

A high performance vapor barrier once again can eliminate one of the variables which leads to the condition in the first place. 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. Should you put a vapor barrier under concrete slabs.

There are other manufactures like w r. 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. 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. Thin plastic like this is often called a vapor retarder meaning it slows the vapor down but doesn t stop it.

By reducing the moisture gradient and diffusion in your slab you can virtually eliminate efflorescence caused by under slab water vapor migration. Why and how is there moisture in concrete slabs. 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. 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.

There is always water underneath the ground while it might not be near the surface it is there. Vapor barriers under concrete floor slabs. 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. Too much moisture in concrete is a problem because it can cause ph changes that destroy adhesives.

Meadows vapor barrier is called perminator it also comes in 10 mil and. Months or years from now the water table link might rise and the water will pass through concrete in water vapors with a. 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.