Vapor Barriers

All Around Roofing: Honest Roofers Denver

Most building codes specify that a vapor barrier must be used when a home is built. In addition to newly constructed houses, older homes also benefit from the use of a vapor barrier. Experienced Denver roofing crews can install different types of moisture barriers that help to protect homes against the damage caused by condensation and water infiltration that may result from roof leaks and ice dams.

Some types of insulation come with a vapor barrier already attached to them. This material offers an enhanced level of convenience, as the installers can put up the insulation and barrier all in one step. The most common type of insulation with a barrier already attached is fiberglass rolls with a Kraft paper backing. If an attic’s insulation already contains unfaced fiberglass, but the amount of insulation does not meet the U.S. Department of Energy’s recommended R value, roofers can add a layer of faced fiberglass right on top of the existing insulation. If the current insulation already has a paper backing, then the roofers can add unfaced fiberglass in a perpendicular orientation.

Another popular option for vapor barriers is four millimeter or six millimeter polyurethane sheeting. When there is unfaced insulation in an attic, a layer of the four millimeter polyurethane can be attached on top of it with a staple gun.

The roofers will use duct tape to secure the seams of the sheets. If the existing unfaced insulation is not sufficient, more of it can be added, and then the vapor barrier can be installed. There should never be an insulation sandwich, which consists of a vapor barrier, then insulation and another barrier. This can cause the insulation to lose effectiveness.

In very damp climates, the roofers might recommend applying a vapor barrier paint to the wood. This can be done without creating an unwanted insulation sandwich. The paint is best applied when the roof is being attached, as the roofers can paint it on and then attach the pieces of wood sheathing. Painting the plywood boards is more difficult when they are attached to the roof’s trusses, as the pitch of the roof may make it physically difficult to do the painting. The paint fumes can also be a problem in enclosed attic spaces. For optimal results, the roofers will apply a vapor barrier primer followed by a waterproof vapor paint after the primer has dried. The paint needs about 24 hours of drying time and then the roof can be insulated.

The roofers from All Around Roofing of Denver can answer any questions you have about siding or flat roof systems. Ask a Question.