Provided you're not claustrophobic, installing a vapor barrier is a project most homeowners can DIY. You will need to calculate the square footage of your crawl space, so you can buy the appropriate amount of liner.
While it is possible to do this job by yourself, it helps to have at least one helper to pass items through the crawl space door and to help with rolling out the plastic and taping the seams. It may also be beneficial to wear a face mask so you don't inhale debris or damp moisture that may contain bacteria and mold.
Drywall works too, and is pretty much the standard for this sort of thing. You could also use plywood or anything else that can act as an air barrier while still being vapor permeable to allow for some inward drying.
How To Install a Vapor Barrier in a Crawl Space. Cover the crawlspace floor with a single layer of plastic moisture polyethylene vapor barrier. Overlap any seams and tape them with waterproof seam tape. “Make sure you overlap the plastic at least 12 inches,” Church says.
You can use plastic if you put polyethylene between your drywall and the wall studs. This way, you should get a tighter wall without trapping moisture inside the exterior walls. If you are framing out a below-grade basement, however, do not use plastic as a vapor barrier.
Because a vapor barrier is a low permeable barrier, it keeps moisture from passing through. This is beneficial to keep moisture away from a dry surface but will trap moisture behind it if installed on a water-damaged concrete wall, causing the wall to fail further.
Plastic and aluminium foil is the most frequently used of all materials as a vapour barrier. It is usually offered as a roll.
Depending on where you live, the vapour barrier will either go on the inner surface of the insulation (if you live in a cold climate) or the outer surface of the insulation (if you live in a hot climate). It's safe to say that a vapour barrier will be needed for almost all projects.
Standard OSB (and other wood panel types such as plywood, particleboard and MDF) are not ideal as an air and vapour tight layer as their air and vapour permeability is variable and can vary greatly between production cycles and production sites.
“For minor projects, the absence of a vapor barrier leads to water intrusion, leading to an unstable foundation or a cracked slab.” The American Society for Testing and Materials (ASTM) outlines national standards for underslab vapor barriers.
No, DuPont Tyvek is not a vapor barrier. It is breathable, allowing moisture vapor to pass through it.
Not every plastic tarp can create a vapor barrier. Pay attention to thickness when looking for the right plastic sheathing for your crawl space. At South Central Services, we install a minimum of 12 mil thick sheathing. Anything thinner than 12 mil is not vapor permeable, but will likely not stand the test of time.
Materials such as rigid foam insulation, reinforced plastics, aluminum, and stainless steel are relatively resistant to water vapor diffusion. These types of vapor retarders are usually mechanically fastened and sealed at the joints.
Rubber vs.
Vapor Barrier: Both materials act as effective vapor barriers, preventing moisture from seeping through. However, rubber is more durable and less prone to tearing or puncturing.
House wrap is not a vapor barrier. In fact, serious problems can arise from using solid material like polyethylene sheeting as house wrap when a similar vapor barrier is installed to the interior. Moisture can become trapped between those barriers, leading to mold, decay, and other damage.
Clear polyethylene is the most basic, plastic barrier film available, as well as the most economical, and is best suited to interior wall applications over framing and insulation.
Yes, covering your insulation with a vapor barrier plastic before installing drywall is crucial.
Install a New Vapor Barrier
If your vapor barrier was damaged or not installed correctly, it's important to replace it with a new one. This will help prevent moisture from seeping into your crawl space and creating the perfect environment for mold growth.
Single Sided Foil Tape is an adhesive jointing tape designed for sealing over the face of vapour control layer membrane joints. This acts to stop the penetration of water vapour through the membrane joint, effectively ensuring that the vapour cannot condensate on the cold side of the insulation.
Have you ever noticed that condensation gathers on the foil when it has been used to cover hot food? This is because aluminium foil is moisture-resistant and acts as a vapour barrier. It is also waterproof (water-repellent), draught-excluding and windproof.
The product also can be used as an effective vapor retarder. The aluminum facing also reduces radiant heat transfer for added R-value or as a radiant barrier and is available in 1000 square foot rolls 54″ wide.
Unless otherwise indicated by the design professional(s) of record, unfold the vapor barrier to completely cover the placement area. Overlap all joints/seams a minimum of 6 inches. Ensure the vapor barrier is clean and dry when applying a manufacturer's engineered seaming tape or approved method.
Moisture barriers block both liquid water and water vapor, while vapor barriers focus on blocking water vapor only. Many products do both jobs, but you should know what your barrier is designed to do and pick the right one for your project.