Built-Up Roofs

Built-up roofs are one of the oldest and most dependable methods for roofing. Built-up roofs are made by applying multiple plies of roof felts laminated together with bitumen. The materials typically used for built-up roofing are polyester, fiberglass or organic bitumen-saturated felts. The surface of a built-up roof is typically asphalt, granulated cap sheet or gravel.

Decor has extensive experience with the installation, maintenance, and repair of built-up roofs. With more than 30 years of experience in the roofing industry, our roofers are among the best. We are extremely knowledgeable and have an in-depth understanding of the components of built-up roofs and are happy to answer any questions you may have about the installation or maintenance of this roofing system.

We do complete installations and are experts in commercial roofing, maintenance, and repairs. We have strong vendor relationships and can offer you competitive pricing for the best products necessary for your built-up roofs.

How Built-Up Roofs Are Installed

Our roofers understand the importance of quality commercial roofing installation. Built-Up Roof installation is a three part process:

In built-up roofs, base sheets are the first piece of roofing material installed. They are nailed down and fastened to the deck or substrate.

After the base sheets, the felts are installed. Felts can be installed with either hot asphalt, coal tar, or cold-applied liquid adhesive. 25 to 30 pounds of hot asphalt or 20 to 25 pounds of coal tar per 100 square feet (roof square) are applied between each felt ply. Adhesive is the last step for installing the felt and three to five gallons of adhesive is used per square.

The final step of installation is the surfacing. Cap sheets use the same amount of bitumen or lap cement for installation that is used to install the plies of felts. Gravel or slag flood coats take around 60 pounds per square of asphalt or 70 pounds per square of coal tar is applied. Once the tar or asphalt is applied, 400 – 500 pounds per square of gravel or 300 – 400 pounds per square of slag are used to embed the roof.

All of the steps of installation should be handled with extreme attention to detail. Our roofers only offer the highest quality and professional work for your commercial roofing needs.

What Roofing Decks Qualify

Built-up roofing can be installed on almost any type of roof deck. Wooden roof decks will require the installation of a rosin sheet and base sheet to prepare the surface. Steel roof decks require a the thickness of at least 22 gauge and some type of approved insulation that provides a substrate.

Manufacturers need to be consulted before installing a built-up roofing system to a polyisocyanurate roof. Manufacturers will not permit a roof if the felts are applied directly to the polyisocyanurate, and cover boards like wood fiber or perlite are needed. If adhesives are being used to attach insulation to the deck, make sure the roofing materials manufacturer is consulted before this is done. Our roofers are committed to taking each of these important steps seriously.

Concrete roof decks need to be thoroughly cleaned before installing a built-up roofing system. Thermal insulation is often used to provide a substrate. Thermal insulation can be attached by mechanical means, adhesives, or even hot-mopped.

Cement fiber roof decks need to have a base sheet or insulation put on before a built-up can be installed to the roof. Insulation needs to be installed in two layers and have all the joints offset and staggered at least twelve inches apart.

Built-up Roof Repair

Overall, built-up roofs are pretty durable. However, strong winds can blow gravel away from the roof’s surface, exposing it to heat and sun and causing the roof membrane to blister. Over time, you may start to notice leaks if bare patches in the gravel persist.

Regular maintenance and inspections can prevent most major problems with built-up roofs. If repairs are necessary, we provide 24/7 emergency service to quickly stop any intrusion and make permanent repairs to the roof.

Lifespan of Built-Up Roofs

Service lives of roofing are dependent on many factors like the area, weather conditions, the materials used, how the roof was installed and many other factors. Each additional ply to a built-up roof adds five years to the roof’s life. Three-ply roofs last for 15 years, four-ply last for 20 years and five-ply last for 25 years.

The most important factor in longevity is the installation. Make sure your built-up roof is installed property by relying on the experienced team at Decor for your built-up roof installation, repairs and maintenance.

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