Flatfoam and Singleply Roofing

Roofs with an almost flat pitch are called low-slope and often require special materials when installing new roofing. Traditional shingles are usually designed for roofs with a pitch of at least a 4:12, and in many jurisdictions they can't pass local building inspections when installed on a low-slope roof. An almost flat roof needs a material that remains moisture proof even when water or snow remains on the surface for long periods of time. If you have a low-slope roof, a good solution might be flat foam/single ply roofing.

Are there different types of flat foam/single ply roofing?

Flat foam/single ply roofing gets its name from the sheet of foam that's applied to the sheathing of a low-slope roof and the single ply waterproof membrane that covers it. The thickness of the foam can vary depending on the application, but in most cases it is at least 1 1/2 inches deep. The foam serves three primary purposes:

1. provide protection to the rubber membrane from the roof sheathing
2. increase the roof's insulation to make it more energy efficient
3. aid in roof drainage

The rubber membrane is available in various widths and thicknesses and is normally attached to the roof using one of two methods. The first technique is called attaching the membrane mechanically and consists of using long screws and plates that are fastened down through the rubber and into the roof framing below the foam. The plates and screws are covered by overlaps in the membrane which are then hot-air welded.

The second technique involves attaching the foam to the sheathing and then using adhesive to install the membrane. The roof, your contractor's preference, and the amount of wind your home receives can determine which method is best for your situation. A mechanical installation is normally considered more durable but can also be more expensive.

How long does flat foam/single ply roofing last?

The thickness of the rubber membrane, the installation process, and the product brand can affect how durable a flat foam/single ply roof is and also how much it may cost. Many manufacturers require that the contractor doing your installation have training from the company in order for their warranty to be valid. Some of the more well-known manufacturers in the field include the following:

1. IB Roof Systems
2. Carlisle-Syntec
3. Firestone Building Products

IB Roof Systems offers a limited warranty of 15 years for their 50 mil membrane and if you upgrade to 80 mil, you can receive a 25-year warranty. Costs can vary widely as labor is normally included as a part of a flat foam/single ply roofing installation. The thickness of the foam and membrane can also cause pricing to fluctuate. Flat foam/single ply roofing is priced per square foot, and an average price for materials and installation of a 60 mil roof may range from $3 to $5 per square foot.

What about energy efficiency?

Not that long ago just about all rubber membrane roofs were black, which meant that they could get very hot during the summer months. That heat was often transferred to the living spaces below and could cause your cooling costs to skyrocket. Many rubber membrane manufacturers now offer "cool roof" options featuring lighter colors which can reflect radiant sun heat. Firestone Building Products' EcoWhite and Carlisle-Syntec's Sure-White membranes are both considered energy saving roofing systems that can earn LEED credits.

How to get started with foam/single ply roofing

Installing flat foam/single ply roofing is quite a bit different than traditional shingles, and many roofing contractors lack the knowledge and experience to apply it correctly. An improperly installed rubber membrane on a low-slope roof can cause expensive water intrusion damage to your home. The form on this page can assist you with finding reputable, properly experienced contractors in your area, or contact local custom homebuilders for recommendations.