What is the best plastic to put under concrete?

The most commonly used vapor barrier under concrete slabs is polyethylene (poly) plastic sheeting with a thickness of 10 mil or 15 mil.

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Is it a good idea to put plastic under concrete?

“Without a vapor barrier, concrete will deteriorate much faster through water vapor intrusion which degrades the quality of the concrete over time and can lead to foundation and building failures, like Surfside Condominium Collapse in Miami, Florida,” says vapor barrier plastic sheeting expert and Americover account ...

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What is the best plastic for under concrete slab?

The American Concrete Institute (ACI) also recommends a minimum of 10 mil polyethylene or thicker for vapor retarders under concrete. According to its Guide to Concrete Floor and Slab Construction ACI 302.1R-15, thicker poly provides a better barrier and is also more puncture resistant.

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How thick should plastic vapor barrier be under concrete?

A vapor retarder that is torn or punctured provides a pathway for moisture to enter the slab from below. The American Concrete Institute's Guide for Concrete Floor and Slab Construction recommends that the thickness of the vapor retarder be at least 10 mils.

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Can you pour concrete over plastic sheeting?

What thickness of plastic do you need under concrete? Thicker plastic polyethylene sheeting between 10 and 15 millimetres should be used under concrete. This sheeting is more durable than most plastic sheeting and almost impermeable to water.

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Why a Plastic Vapor Barrier Under Concrete Slab - Mondays with Mike

37 related questions found

Will cement set on plastic?

If your wood has not already been treated, you may have to purchase a commercial agent and apply it yourself. Concrete also sticks very well to plastic. Treating plastic with a release agent prior to coming in contact with concrete is the best way to ensure your plastic buckets and tools remain free of dry concrete.

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Will concrete dry under plastic?

The most efficient way to cure concrete is to use a plastic cover. The covers are placed on freshly poured concrete until the concrete has a chance to dry. Plastic concrete curing covers seal off concrete and prevents water from evaporating.

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Should you put plastic under concrete outside?

You are not required to have a vapor or moisture retarding barrier for outside concrete pads or unheated buildings. Although a vapor or moisture retarder or barrier is not necessary beneath concrete floors used for unheated carports, driveways, and outbuildings, some DIY enthusiasts and builders recommend it.

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Does concrete need to breathe?

An excess of moisture is the #1 contributor to floor system breakdowns. How does it happen? Well, as we mentioned above, concrete breathes. It may feel solid but it's actually porous, and riddled with capillaries.

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How do I stop moisture coming through my concrete floor Australia?

Liquid epoxy DPM for existing concrete floors

There are a number of benefits to using a liquid epoxy DPM: An epoxy liquid membrane is applied to the floor itself and creates an impermeable layer meaning that water stays in the concrete slab.

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What is best to put under concrete?

Medium gravel, which is 1.8 cm (3/4 inch) in diameter, is the best material for a concrete base. To cover a 4 inch thick concrete slab, you'll need 3 inches of gravel. Because gravel surface is level, you can easily estimate the number of yards of concrete required. In fact, it is impossible to compact gravel.

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What kind of plastic is used for vapor barrier?

Reinforced polyethylene plastic sheeting (poly) comes in a variety of thicknesses and strengths. A 6 mil thick poly is commonly used as a vapor barrier and offers short-term savings to the homeowner.

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What are the disadvantages of using plastic in concrete?

Using synthetics like plastic in concrete generally weakens the material because they do not bond to the cement mix as well as sand.

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Do you need black plastic under concrete?

If you have a concrete floor in continuous contact with a source of moisture, you will have problems. This is why a vapor barrier under concrete is essential. Vapor barriers are a way to keep moisture from getting into the concrete.

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Does plastic make concrete stronger?

They discovered that replacing sand with plastic bottles ground up into similarly sized and shaped particles resulted in concrete that was almost as strong as conventional concrete mixtures, and it could save 820 million tons of sand per year and reduce plastic waste levels.

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How do you keep moisture out of concrete floor?

Apply a concrete waterproofing sealer over the entire surface of the floor in an even layer and allow it to dry completely. Apply a second layer of concrete sealer to ensure maximum protection. Allow the sealer to dry for at least 24 hours before walking on or placing the furniture back onto the surface.

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What does black plastic do under concrete?

Vapour barriers are the black (or orange) plastic that builders put under residential house slabs. They do this for two main reasons: to prevent moisture from the soil permeating up through a slab and into a house (also known as rising damp); and.

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What will stop concrete from sweating?

Use a dehumidifier to remove moisture from the air and reduce the condensation. Use a penetrating sealer to seal the concrete and keep out moisture. We recommend using a concrete densifier first as a primer followed up by a penetrating concrete sealer.

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How long to leave plastic on concrete?

A: The longer concrete stays damp after it's poured, the stronger it will be. Cover it with plastic or damp cardboard for a minimum of three days. A week is even better. For large slabs there is even some benefit at 28 days.

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What happens if you don't install vapor barrier?

Without a barrier, cold air meeting warm heat-generated air inside a house would create condensation in the walls, leading to mold growth and other problems. Interior walls that may need vapor barriers are those surrounding humid areas, such as bathrooms, where moisture can seep through the walls and cause damage.

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What happens if you don't water concrete?

Concrete that is not moist-cured at all dries too rapidly, and reaches less than half its potential design strength. It will also have a greater number of shrinkage cracks.

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Why do they put plastic under concrete slab?

What is Vapor Barrier? A plastic sheet that is placed between the base and the concrete slab. Always placed beneath the rebar or wire mesh and on top of the gravel base. The sole purpose of the vapor barrier is to prevent moisture from penetrating through the concrete.

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How do you keep concrete from cracking when drying?

Reducing concrete cracking
  1. Keep an eye on the temperature. ...
  2. Prevent excess water. ...
  3. Look into using synthetic micro fibers. ...
  4. Brace formwork. ...
  5. Use formed joints. ...
  6. Explore pre-curing options. ...
  7. Provide sufficient concrete cover. ...
  8. Start curing the concrete as quickly as possible.

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