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.
The most commonly used vapor barrier under concrete slabs is polyethylene (poly) plastic sheeting with a thickness of 10 mil or 15 mil.
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.
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.
Vapour barrier: A material specifically intended to restrict the transmission of vapour. Typically used for moisture proofing. Only use materials which are VCM Class 1 to AS/NZS 4200.1 and are classified as Water Barrier to AS/NZS 4200.1.
The IRC recommends builders install a Class-I or -II vapour retarder on the interior side of homes in climate zones 5 (Cold) and north, and in the Marine 4 zone. However, if you air-condition your house in the summer, your might trap condensation in your roof or walls for part of the year.
You don't “need” a vapour membrane under a shed concrete slab but it is still a good idea to install one. It is still a good idea to have protection against rising damp even though you don't strictly need it.
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.
“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 plastic sheeting expert and Americover account manager Charlie ...
Without a vapor barrier, moisture would continually wet the bottom of the slab, as vapor will continuously drive from the high humidity below slab to the relatively low humidity above the slab.
By sticking with a thicker mil plastic, you'll have a dryer crawl space and better air quality. We recommend using a vapor barrier of 16 mil or higher. This translates into a permeance rate of only .
The best sub-base for a concrete slab is gravel. The soil has to be prepped first before the gravel can be laid down; pouring concrete directly onto rock is not considered a best practice. You can use different kinds of gravel for the subbase as long as it is clean and uniform in shape and size.
This means that in addition to groundwater working its way up, you also have a moisture-laden flooring surface slowly releasing water vapor for years. Concrete needs to breathe; it's the nature of the beast.
Black barriers are more effective at stopping moisture evaporation, compared with the clear barrier. The black color hinders the growth of plant seeds that may reside beneath a home's crawlspace. Plants naturally send moisture into the air, creating more moisture.
Vapor barriers should be at least 6 mil in thickness to effectively cover the area and create a moisture barrier.
PROTECTIVE BARRIER: This is the ideal cover for heavy equipment and machinery; it acts as a protective barrier from dust, vapor, moisture, paint and more. QUALITY MATERIAL: Made in the USA from industrial grade polyethylene with a 10 mil thickness for extra durability, the tarp meets all building code specs.
Plastic should be placed under a concrete slab to protect it from moisture damage. Moisture from soil can penetrate the concrete causing it to crack with time and potentially risking lots of structural damage. A vapour barrier put under a concrete slab such as plastic sheets can protect it from this.
Subfloor Material
Therefore, in high-humidity areas, moisture will move to a relatively low-humidity area, even through concrete. Therefore, because concrete is porous, it's a good idea to install a vapor barrier over your concrete subfloor before installing your flooring.
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.
Standard Concrete Slab Thickness In Australia
In Australia, concrete slabs must be fixed in adherence with the Australian Standards AS 2870 and AS 3600. The most common slab thickness in Australia is between 85mm and 100 mm. The thickness of concrete slabs is usually stated in specification documents.
Overview of the Standard
AS 2870 sets outs the method for determining the classification of a site and the design and construction requirements for slab on ground, stiffened rafts, waffle slab, strip footings, pad footings and piled footings.
Most concrete contractors want a mix of coarse and fine aggregate to create a compactable base that is going to be safe for settlement and drainage. Crusher run (a mix of crushed stone and stone dust) and #57 coarse aggregate are two of the best base materials for concrete slabs.