Flat Roof Membranes
Tuesday, March 6, 2018 at 1:06PM

March 2018

by Bryce Given

In the Pacific NW, there are many different types of roofing materials that can be applied onto a flat roof of a home or commercial building.  These include metal, silicone spray foam, EPDM rubber, single ply, built up, and bitumen based.  Bitumen is asphalt or coal tar based material.  Single ply, built up roofing (BUR) and torch down roofing are the most common types we see installed in the Pacific NW.  So what are the general differences between the common roofing types? 

Single Ply Membrane Roofing:

There are three kinds of single ply roofing:  1) polyvinyl chloride (PVC), 2) thermoplastic polyolefin (TPO) and 3) ethylene propylene diene monomer (EPDM).  Single ply membranes come in thicknesses between 40 mil and 80 mil, depending on manufacturer and type.  Single ply can be mechanically or adhesively attached to the underlying substrates.  PVC and TPO seams and laps are hot air welded or chemically bonded.  

Installation costs vary by site conditions, roofing contractor, manufacturer and material type and thickness.  Generally, a square foot allowance cost for labor and material may be $9 to $10 for PVC’s and $7 to $8 for TPO’s. 

Installation costs are generally $7 to $8 per square foot.

Installation costs are generally $7 to $8 per square foot.

Torched Down systems 

Installation costs are about $6 to $8 per square foot.

Regardless of the type of roofing or extent of the project, CDR recommends that two or more bids be obtained for the work and contracts be in writing and reviewed by an attorney before signing.  Additionally, CDR recommends that manufacturer and installation warranties be researched and inspection protocols be followed during and after installation to maximize the life and warranty of the roof system.

Article originally appeared on Construction Dispute Resolution, Inc. (http://www.constructionresolution.com/).
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