Question

Does anyone have experience with a spray foam roofing product for my roof - like an elastomeric compound?

Asked by Trent
Washington, DC

They apply and it supposedly lasts 10 years. Basically you spray the whole roof with it and you can get away with not replacing your roof for awhile . It is supposed to cover seams and cracks and provide insulation. Part of me thinks getting a new roof would be smarter and probably better environmentally but I thought I would ask.

Answer

Michael Holcomb

Answered by Michael Holcomb

Byron Center, MI

Alliance for Environmental Sustainability (Headquarters)

September 22, 2011

Trent, I see a couple of red flags in your question. Salesmen often make claims that are false or misleading by omission. 

  • Is the material "supposed to last" 10 years?
  • Or is there a 10 year, no leak warranty?
  • Does this cover replacement or repair?
  • Is the warranty prorated over the 10-years?

If I had a flat roof I would weigh the cost of the coating, the warranty and my expected tenure in the home. 

Insulation value

It is highly unlikely that an elastimeric coating will add insulation, regardless of the type of roof.

It may be reflective and reduce summer cooling bills by reflecting heat back into the atmosphere but add to your heating costs in the winter for the same reason (no solar gain).

Aesthetics

If you have a traditional sloped roof with 3/1 cut tab shingles you might not be very happy with the final appearance of the product once it is installed.

  • Spray coatings over asphalt shingles are unsightly if the shingles are curled, cupped or cracked.
  • I've inspected dozens of sloped roofs with spray coatings and have never met a satisfied customer.
  • It can make your home difficult to sell without tearing off the old roof and replacing it regardless of age.
  • Appearance is everything.

Factors to consider about roof replacement

A good case for replacing a flat roof that is near the end of design service life is timing.

Improving flat roof insulation can only be done properly after the roofing material is removed. Tear off is costly so you will need to determine the return on investment. You also want to make sure you have a strong warranty against leaks and replacement for a specific period of time.

Tips for working with the roofing contractor

Take time to check contractor references, especially clients that have had their roof replaced 2 or 3 years ago.

Some other tips:

  • Make sure the contractor carries proper liability and workman's compensation by asking for current insurance certificates.
  • Negotiate the lowest down payment possible.
  • Make sure the contractor is bonded in the event he takes the down payment and skips town or gets hit by a bus.
  • Hold back 15% until you can verify that all the work is completed in a workmanlike manner.
  • You can hire an independent (ASHI) inspector to review the work before final settlement.
  • Get your warranty in writing and check, double check references.

Good luck.

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