Polythene Sheet For Concrete Slab

Currently what little evidence i have indicates that polyethylene under slabs degrades over time.

Polythene sheet for concrete slab. Keep w c at or below 0 5. Under slab vapor retarders play a very important role in retarding moisture from coming up through the concrete and into the structure. This is important for example if polyethylene used under a slab as a radon. Polyethylene sheeting under concrete slab.

When a concrete slab dries it shrinks. A vapour barrier in concrete slabs full basements and crawl space construction. Starting with lower water cement ratio concrete will let the slab dry faster. The order upwards for the slab is.

So that concrete can take its own time for dry and avoids the possibilities of cracks and other damages. Often referred to as construction and agricultural film c a film it is used most frequently in concrete slab preparation wall construction floor underlayment crawl spaces pit covers and landscape mulching. A concrete vapor barrier is simply a sheet of polyethylene plastic visqueen placed directly on top of the sub grade before the concrete floor or slab is poured to help keep moisture from the soil from passing up through the concrete. A slip sheet is a layer of material placed between the slab and the subgrade to reduce the friction between them.

Oversite concrete slabs employ a 1000 guage 250 microns polythene sheet laid underneath the concrete to prevent the moisture from being absorbed. Vapor barriers also block gases such as methane or radon. Undisturbed soil crushed stone 4 inches of type i eps 6 mil polyethelene sheet another 4 inches of type i eps and then the 4 inch concrete slab for a total insulation value of r30. Typical 8 mil polyethylene sheeting costs 5 to 7 cents per square foot.

Construction poly sheets are mainly used for the construction sector. This is because polyethylene allows the passage of oxygen and carbon dioxide. These products are made. Is there information available such as research case studies and field experiences that documents the long term performance of polyethylene sheets used as vapor barriers beneath concrete slabs on grade.

However this list is a summary of current applications. Today most experts feel very strongly that engineered films designed specifically for use as vapor retarders should be used as vapor retarders. The general standard employed for the testing and verification of polythene sheets for use as a vapor barrier is the astm4397. Roly poly heavy duty 6 mil black polyethylene sheeting on a roll is perfect for many industrial commercial construction residential uses.

As the concrete begins to shorten some cracking can occur because the subgrade resists slab movement. Slip sheets reduce this frictional resistance and help reduce cracking.