The Roofing Resource Blog

Flat Roof Repair- 4 Common Types of Flat Roofs We Recover

Mon, May 30, 2016 @ 08:00 AM | Perry

Many building owners are surprised and optimistic when they find out about how their existing roof could be recovered with a PVC membrane saving the cost and mess of tearing off the old roof. The substantial cost savings of recovering your existing roof with a PVC membrane as opposed to tearing the old roof off and replacing it is enough for even the most skeptical building owners to give it a second look.

Here are 4 commonly found types of flat roofs within our service area that we recover using our PVC flat roof recovery system.

  • Tar and Gravel
  • Rubber Roofing
  • Asphalt Rolled Roofing
  • Ballasted Rubber Roofing

Tar and Gravel Flat Roofs

Tar and gravel roofs are great candidates for a PVC recovery system because they save a building owner a large amount of money. The tear off on tar and gravel roofs can be tough, messy, and expensive so leaving the existing roof in place and recovering it can save 50% or more of the total cost of a flat roof repair. They are easily recovered by leaving pea gravel in place and installing thin layer of insulation over the gravel. The 1/2" of insulation flattens out the surface by absorbing the shape of the gravel. Once the insulation is installed over the gravel the roof is ready to be recovered with the new PVC membrane.

Tar and gravel roofs are characterized by the small pea gravel that is partially stuck in tar. These types of roofs were common on shopping centers and larger sized commercial buildings with flat roofs built in the 60's, 70's, and 80's.

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Rubber Roofs

Rubber roofs are by far the easiest and least expensive type of flat roof to recover. The rubber roof is typically glued down and stretched tight offering a solid, flat surface to recover. The PVC membrane is 100% compatible with EPDM rubber roofing and can be installed directly over the rubber without any insulation or separation sheet.

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Asphalt Rolled Roofing 

Rolled roofing or modified roofing sheets can be recovered by separating the asphalt based roofing product from the PVC membrane. This can easily be done by installing a layer of insulation over the roof before installing the PVC membrane. A separator sheet can be installed along the parapet wall before the PVC membrane is used to cover them.

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Ballasted Rubber Roofing 

Ballasted rubber roofing is simple to distinguish, it is a flat roof covered in large round river stone. Underneath the larger rock lays a rubber roof. The purpose of the large stone is to weigh the rubber down to hold it in place as this type of rubber roof is not glued down. Ballasted rubber roofs can be recovered with our PVC membrane but unlike the tar and gravel roof, the large stone must be removed. We use a large vacuum truck to that literally sucks the rock up off the roof. We can easily remove 20,000 plus sq. ft. per day of large stone if a dump area is close for the rock to be deposited. Once the rock is clean off the roof the PVC lay over can start immediately afterwards. 

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The ability to recover an existing flat roof and drastically reduce your flat roof repair cost is an option most building owners are glad to explore. To see if your flat roof is a good candidate for a recover, call us to set a free site visit at (812) 274-0444 or to learn more about our flat roof repair options download our guide. 


Topics: PVC membrane, Rubber Roofing, Flat Roofing, Commercial Roof