The Cost of Installing a Quality Vapor Barrier
We most often get questions regarding the cost of the Your Crawlspace vapor barrier system. Contractors and wholesalers are welcome to call (843) 543-9003 to discuss volume discounts and payment options. You can calculate how much materials you need or you can click the “Receive a Quote” button on our website's homepage and we’d be happy to calculate the materials you need and provide a quote.
The first step in calculating the cost of a crawlspace vapor barrier is to calculate the floor area of the crawlspace. There’s no need to be exact. Remember that you’ll need a little extra for seam overlap. Our vapor barrier is sold in 7’ X 50’ rolls (350 square feet per roll) so divide the square footage by 350 and round up to determine the number of rolls you’ll need. For example, if the crawlspace is 30’ by 40’, your crawlspace floor area is 1,200 square feet. Divide the square feet by 350 square feet per roll equals 3.43. Rounding up to 4 gives you the number of rolls of vapor barrier you’ll need to cover the floor area.
Since the Your Crawlspace vapor barrier is a 35 mil coated geofabric, there’s no need to purchase an underlayment recommended by most other material retailers at a cost of 20 to 30 cents. That’s a savings of $250 or more. A geofabric is a synthetic felt that is lightweight yet very strong and puncture resistant. A goefabric protects the vapor barrier from damage. In addition, since geofabrics create an air space between the actual vapor barrier and the crawlspace ground, they play an important role in soil gas mitigation that cause crawlspace odors and, like radon, may even be dangerous. Geofabrics were originally designed as a highway underlayment.
Our Crawl Curtain also comes in 50’ lengths and 2’, 3’, and 5’ widths. First, count the number of support piers and note their size. Most support piers will be single block (8” X 16”) or double block (16” X 16”). Remember that the purpose of wrapping the piers is to provide an air and waterproof seal for the floor vapor barrier. It is only necessary to seal the piers 6” to 12” up from the crawlspace floor, so the 2’ wide material works perfectly. One 50’ roll will wrap 11 single block piers and 9 double block piers.
Let’s assume our example has ten double block support piers. Our 1,200 square foot crawlspace example has a total of 140 linear feet of exterior walls. Three 50’ rolls of Crawl Curtain will seal the walls with plenty of material for seam overlap. Most crawlspace experts (Advanced Energy, the EPA, and the US Department of Energy) recommend a 4” to 6” termite inspection gap at the top of wall. You’ll also need enough width to lap the material 6” to 12” out onto the floor for a good overlap. So, in our 1,200 square foot example, if the walls were three blocks tall (24”), a 3’ crawl Curtain would allow for a six inch inspection gap and enough material for a 6” overlap on the floor. Three 3’ X 50’ rolls would be required.
And what about sealing the piers and wall? The Crawl Curtain attaches and seals with a ¼ bead of our recommended low VOC polyurethane adhesive. Not only will our system save hours of installation time, it won’t be necessary to purchase Tapcon screws, washers, a hammer drill, and masonry bits; or a ramset gun, nails, and black-powder loads; or pressure treated furring strips and concrete nails. In all of the alternative installation methods, it is also necessary to seal the attachment with caulk. So if you're going that route, add caulk to your shopping list too.
Our recommended polyurethane adhesive is sold in 10 ounce and 29 ounce tubes. A 10 ounce tube will provide a ¼” X 32’ inch bead and a 29 ounce tube will provide a ¼” X 89’ bead. Our 1,200 square foot crawlspace will require six 10 ounce tubes of adhesive or three 29 ounce tubes of adhesive We’re almost done.
The last consideration is seam sealing tape. Our seam sealing tape is a 7 mil white polyethylene tape with a waterproof synthetic rubber adhesive. It is sold in 3” X 180’ rolls. We recommend 1 ½ rolls of tape for every roll of floor vapor barrier. Our 1,200 square foot crawlspace would require six roll of seam tape. We’re done! That’s all you need - only four products and a little labor. Let’s review our shopping list: four rolls of vapor barrier, three rolls of 3’ Crawl Curtain and one roll of 2’ Crawl Curtain, three 29 ounce tubes of adhesive, and six roll of seam tape. You’re buying the safest and most easily installed vapor barrier system available anywhere and saving yourself hundreds of dollars in the process.