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Manufactured Housing

Compare cost, benefits of single-membrane roof

By LEN BONIFIELD
Published December 10, 2005

Third of four parts.

What is single-membrane roofing and why should you consider it as an option when reroofing your manufactured home?

The initial cost of a single-membrane roof is higher than the traditional shingle roof. So why spend the extra money? Single thermoplastic membrane is available in white, the most common color, or in a shingle look in tan, charcoal, or green. Single membrane lasts longer than typical asphalt shingle. It is waterproof, even on low-pitched roofs. It is durable in extreme weather. It is an energy-efficient insulation system. It noiselessly seals out wind, rain and salt spray. It is maintenance free, looking new year after year. It is a quick and worry-free installation, usually one day.

Single-membrane roofing is installed over your existing shingle roof, adding another layer of insulation and sound deadening.

Dave Smith, a consultant with Tropical Roofing in St. Petersburg, describes how Tropical creates a single-membrane roof. Workers take precise measurements so they can prefabricate the roof in a warehouse with an 1,100-degree heat welder.

Workers frame the roof for high wind uplift ratings by using 1 x 4 pressure-treated lumber securely fastened to the perimeter of the roof.

The next step is to insulate the roof using 11/4-inch, highly dense, expanded polystyrene foil-faced insulation, which can provide up to 50 percent energy savings.

Then the roof is covered with a flexible thermoplastic polyolefin roofing membrane. One custom section at a time is mechanically fastened through the insulation into your original decking.

Now the seams are all welded along with the ridge cap area, which is doubly protected. These seams are welded at 1,100 degrees, making the seams stronger than the material itself.

All of the vents are removed and replaced with a spun aluminum vent with a heat-welded boot for lifetime protection.

The connections to carports, Florida rooms and sheds are vulnerable to leaking, so the new single membrane roof is extended up to 12 feet over those areas.

The entire roof is then secured with a white aluminum termination bar mechanically attached with stainless steel screws below the roof's edge.

Just how good is this new single membrane roof for insulation and energy savings? One customer installed an electronic thermometer in the space between the interior ceilings and his original roof. He recorded the daily outside temperature and the temperature in the space between ceilings and roof. Every day, it was hotter inside the attic than outside by 30 to 25 degrees on sunny days, 7 to 14 degrees on cloudy days.

Then he tracked the temperatures for two weeks after installation of his single-membrane roof. The interior temperature was always lower than the outside temperature by 6 to 15 degrees.

I talked with two neighbors who have had single-membrane for almost two years. One says his electric bill is 50 percent lower; the other, 30 percent.

Tropical estimated that a single-membrane roof on my 28- by 58-foot, 10-year-old Fleetwood, including the sunroom, would cost around $7,500. Question: Is a lifetime guarantee, never worrying about replacing it, combined with the substantial energy savings, worth the extra cost? Each home owner would have to determine that.

Next: metal roofing.

- Send comments or questions to Len Bonifield at elb@gate.net or write him at 2914 Dollar Bonnet Lane, Lakeland, FL 33810. Please include your e-mail and mailing address. Because of the volume of mail, he can't respond personally to every query. Bonifield is a manufactured-home resident and a past HOA president and former officer of the FMO District 1 board of directors.

[Last modified December 9, 2005, 08:25:05]