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"Visqueen" Vapor Barrier- Will it do the job?

Posted by Nana Hinsley on Mon, Mar 09, 2015 @ 10:16

So often people inquire about, "Visqueen" vapor barrier.  What they are really asking for is some sort of plastic sheeting to use as a vapor barrier/retarder. (Click here to visit the vapor barrier page).

Vapor barrier for concrete

 

Why are vapor barriers used under concrete you ask...Moisture that is in the ground slowly rises to the surface. This is problematic if you are putting tile or carpeting on top of the concrete in the way of flooring.  Vapor barriers AKA vapor  retarders are a sheet of plastic that blocks the water from reaching the concrete slab. 

Can any type of plastic work for this purpose...not exactly.  You see while you may think a 6-mil layer of Visqueen is sufficient, it simply isn't. This liner is not water tight. Additionally, 6 mil plastic gets damaged during the placement of reinforcement and concrete which will create holes that will let the water right up.

Torn Vapor Barrier.jpg

Visqueen has become one of the generic names for plastic sheeting, just as Kleenex has become the generic name for tissue. When someone asks for Visqueen, they are referring to a lesser grade of plastic sheeting. The plastic sheeting known as Visqueen has become a generic name for Construction and Agricultural Grade Polyethylene sheeting (C&A film). C&A film contains up to 25% post consumer recycled content, and is made from the least expensive resins available at any given time. While it is excellent for use in many projects, it is not ideal for any use that requires sustained strength such as a tarp or for use as a vapor/moisture barrier or retarder. People will often do a search for "visqueen vapor retarder", or fire retardant visqueen" when they may be looking for an engineered plastic. An engineered plastic is one that is intentionally designed to meet certain measurable criteria to insure its suitability for the job it is intended for. 

When looking for a vapor retarder/barrier, we recommend  an engineered film like Raven Industries VaporBlock Plus for this purpose to block as much of the moisture, radon, methane and VOC's as possible. VaporBlock Plus engineered films are designed to last forever buried in the soil, where C&A film often completely breaks down within a couple of years. Have you ever dug up some old black plastic? Remember how torn and crusty it was? It's important that today's vapor/moisture barriers or retarders should pass the ASTM E 96 Class A, B and C (standard for under-slab vapor retarders in contact with soil or granular fill).  ASTM E 96 measures in part the "permeance" or how much water can pass through the vapor barrier.  You need a liner that is 0.3 perms or less. In terms of thickness, 10 mils and above will offer much better protection and resistance to moisture transmission.   If you need to over-lap the vapor retarder, 6 inches at the seams, taped and sealed around column and the like.

The bottom line is doing your due diligence regarding vapor barriers and selecting one that is not a "visqueen vapor barrier" and go with  liner that is engineered and tested to do the best job for the application.

Tags: Visqeen vapor barrier

6 Mil Clear Reinforced Films- Why Are They Popular?

Posted by Nana Hinsley on Thu, Mar 05, 2015 @ 01:21

6 Mil clear Reinforced Films  Why are resized 600

Click here to view 6 mil clear reinforced plastic sheeting. 


Are 6 mil clear reinforced polyethylene construction fins the same thing as 6 mil clear plastic sheeting/poly sheeting?  Perhaps comparing it to a 4 wheel drive SUV’s and 2 wheel drive SUV’s can help  with the analog.  The SUV's may look the same in terms of the shape and color of the vehicle, but the performance of the two vehicles vastly differ.  The same can be said when you are trying to compare 6 mil clear reinforced (nylon string poly to 6 mil clear plastic sheeting. Both films can be made from virgin resins, but the strings/scrim reinforced film is much stronger due to the string reinforcement.

 When people refer to "string reinforced"  they are talking about fiber that is placed between two sheets of polyethylene to strengthen the plastic sheeting.  This fiber can be made from a variety of materials such as fiberglass, polyester, polypropylene and others.  Each string type will offer a different set of benefits.  Essentially all those terms are referring to the fact that there is more than just polyethylene in the sheeting.  The string/ fiber is what keeps tears to a minimum.  If the string is laid equally in both directions it follows that the tear will be the same in both directions.

So how do you decide between the string reinforced and the non-reinforced plastic sheeting? The key is defining the results you want from the poly film for the application at hand. If you need a tougher film, then go for the scrim reinforced version. 

Will this film be used outside and thus need UV protection to protect for sun degradation?  Some of the addition that can be added to the 6 mil reinforced  film are grommets, tie‐downs, hems, zippers, drains, and 3‐D custom shapes are an option. Do you need the film to be fire retardant? That is an option as well.

Both films will do a good job when they are used in applications that suit their intended use. 

Tags: Poly Scrim, string reinforcement, scrim reinforcement, Raven IndustriesDura Skrim