Woven vs High Strength Vapor Barriers
- High Strength™ has a 5 mil layer on top of the vapor barrier to improve wear from crawling
- Coated woven has a 1 mil - 1.5 mil top layer.
- High Strength™ uses a film on the top layer not just a coating
- High Strength™ uses strengthened polyethylene ribbons for reinforcement
Woven crawl space vapor barriers
Since 2019 woven barriers have arrived on the crawl space vapor barrier scene as a low cost alternative to string reinforced. 2019 is not the first time woven has been used as a vapor barrier, but it is when it really started to become popular.
Woven
Coated woven vapor barriers are made with polyethylene ribbons woven together to make a cross hatch design similar to a tarp. The purpose of these ribbons is to reinforce the surface of the vapor barrier. The ribbons are woven together on a loom, either a flat loom or a circular loom and then coated with a 1 or 1.5 mil polyethylene layer to hold the ribbons together. The manufacturing industry uses the term "coated woven" to describe this process.
Coated woven vapor barriers became popular because they were far less expensive to purchase when compared to a cord reinforced vapor barrier. There was also a push by some in the crawl space market to offer it as a solution to poor quality string reinforced vapor barriers using recycled plastic that caused unwanted odors.
A pro to a coated woven used to be price, but now that it is a more popular option the price seems to have found its way up near string reinforced. However, the cost to manufacture a coated woven has not changed much.
The biggest disadvantage to a coated woven being used in a crawl space is it only has a 1 to 1.5 mil (0.001" to 0.0015") coating on either side to protect it from the soil and from the more abusive crawl traffic. Once this coating has been compromised it looses its barrier quality. The thin coating must be controlled during manufacturing to specifications in order to not heat the bonding surface too much causing the ribbons to dramatically loose their strength.
High Strength™
High Strength™ (HS) uses a very similar reinforcement to the coated woven. In manufacturing the High Strength™ we stretch the virgin polyethylene ribbons to strengthen them before weaving them on the loom. Polyethylene becomes the strongest just before it breaks. This stretching greatly improves the puncture and tear strength of the HS. To reduce the crawl traffic wear on the High Strength™ we do not use a thin coating on the top white surface, instead we laminate a 3.5 mil 12' wide polyethylene film to the surface using a 1.5 mil bonding layer. That means the High Strength™ has a 5 mil top layer compared to a 1 or 1.5 mil top layer on the coat woven. This gives the High Strength™ much better resistance to crawl traffic damage and wear.
The appearance is nicer as well with a smooth white top layer that gives the WaterProof Pro Seam Tape™ a great bonding surface.