By BUILDER Magazine Staff. No one needs to tell you that the roof is the primary weather barrier on a house and is one of its most important items. A good roof, depending on the material, should last at least 20 years--and some have been known to last up to 50.

But a house cannot live by roofing material alone; it needs help. That's why manufacturers offer products that extend the life of your roofs, keeping your home buyers dry.

One of the best ways to help a roof do its job is to use a high-quality underlayment. Now required by all three major building codes, the products reduce the chances of water infiltration from wind-driven rain or ice dams. "An underlayment is the least expensive insurance policy you can put on your house," says Kerston Russell, division president of Vernon Hills, Ill. based EcoStar. "If builders aren't using one, they are putting homeowners at risk and building inadequate houses."

Stuck up

Ed Farina, senior vice president for Hazelton, Pa. based Polyglass, notes that underlayments come in three basic forms--traditional 30-pound felt paper, self-adhesive asphalt, and various types of polyblend products. Polyglass offers an extensive line of rubberized asphalt underlayments for various types of roofing material. All of these products have a self-sealing feature that helps create tighter roofs because the glue seals around the nails after they have passed through to the sheathing.

Courtesy Benjamin Obdyke

Polyglass' most recent introduction, Polystick TU, is ideally suited to tile roofing products. "PolyStick TU was developed more for the Florida market," Farina says, or for houses being built in warmer areas of the country. "Traditional ice and water underlayment uses a smooth surface, but this one uses a hard rough surface so that tiles will not slide down during installation." The self-adhering product is manufactured using a rubberized asphalt waterproofing compound and a fiberglass-reinforced mat. EcoStar manufacturers a spun-bounded polypropylene product called Aqua Guard that it says is a more versatile product than felt underlayment because it will not crack or dry out in extreme temperatures and is highly resistant to wind blow off. The product also has a melt point of 260 degrees--an important feature in warmer areas, Russell notes.

Courtesy Grace Construction Products

"The thing about underlayment is that you have to make sure the melting point of the adhesive is not too close to the roof's temperature," explains Russell. For example, if the roof gets to 150 degrees and the melt point of the adhesive is 160 degrees or 170 degrees, that's a little too close for comfort. At such a close number, Russell says, "you can have adhesive leaking out the sides of your roof, so you have to make sure the adhesive's melt point is high."

Free to vent

If you build homes in hot climates, a ridge vent is another important product that can mean a lot to your buyers. Installed over the ridge of the roof, the product helps to draw hot moist air outside and pulls fresh air to the attic.

Venting the ridge of a house is good practice, says Farina, because it serves a dual purpose: It helps keep the roof dry, but it also vents moisture from the interior of the house, which reduces the risk of mold growth. Ridge vents are not required by national building codes, but many local codes are requiring the use of them.

Courtesy Tarco Specialty Products

Michigan City, Ind. based Blocksom and Co. offers a natural fiber product called Roof Saver that vents the ridge and can survive the severe winds of Miami and the Southeast coast. Made from high-density fiber on polyester netting, it removes hot air from the attic and eliminates potential damage to the roof, the company says. Rapid Ridge Metric from Benjamin Obdyke in Horsham, Pa., is a nylon and polyester product that will keep roofs dry and tight for a longer period of time, the company says. Melissa Grimes, marketing manager for the company, says the product is designed to protect roofs that have been installed with metric asphalt and fiberglass shingles. Removing moisture from the attic "helps to conserve energy, and it also helps the roof stay dry in warm regions of the country." The product is also a benefit to builders, Grimes says, because it comes with its own 1 U-inch collated nails and installs quickly.

Sticky stuff: Polystick TU is a self-adhering tile roofing underlayment and waterproofing product for steep slope roofs. The product is manufactured using a rubberized asphalt waterproofing compound and a fiberglass-reinforced mat with a granular surface that helps keep tile in place during installation. The manufacturer says the rubberized asphalt seals around the nails for a tighter roof. Polyglass. 800-894-4563.

Courtesy EcoStar

Over ridge: Rapid Ridge ridge vent can be easily installed with any pneumatic roofing nail gun to provide weather protection for metric asphalt and fiberglass shingles. The manufacturer says it also offers insect infiltration protection. The three-dimensional nylon matrix won't dent, crack, or split and allows the product to sit neatly under the ridge cap shingles. Lightweight and flexible, the product comes in 20- and 50-foot rolls and has visible nail lines for installation. Benjamin Obdyke. 800-346-7655. Shields 'n frost: Made with a rubberized asphalt adhesive backed by a layer of high-density polyethylene, Ice amp; Water Shield applied in critical flashing areas can prevent leak problems from occurring and can help extend the life of roofs, the manufacturer says. The membrane is supplied in two roll sizes: 75 feet long by 36 inches wide and 36 feet long by 36 inches wide. It is ideal for slate, tile, cedar shakes, metal, and asphalt shingles. Grace Construction Products. 617-876-1400.

Barrier free: LeakBarrier is a multi-purpose underlayment that can be used under many roofing types, including composition shingles, shake, tile, and metal. Consisting of a fiberglass-reinforced sheet sandwiched between two layers of resin, the product combines the moisture resistance of asphalt with the strength of synthetic resin, the maker says. It is available in 1- or 2-square rolls. Tarco Specialty Products. 800-365-4506.

On guard: Aqua Guard roofing underlayment offers more water protection advantages over traditional felt underlayment, the maker says, because it will not crack, dry, or degrade in extreme temperatures. The product is made of polypropylene, so it also will not degrade, deteriorate, or rip from nails and will be highly slip resistant when installing roofing material. Measuring 300 feet by 4 1/2 inches, each role covers about 10 squares. EcoStar. 800-211-7170.