What is the Best Warranty for a Single-Ply Membrane Commercial Flat Roof?

by | Jul 5, 2023 | Planning and Budgeting

Single-ply membranes are popular with commercial flat roof building owners because they are suitable for most climates, affordable, and long-lasting.

If you’re getting a new roof membrane installed, a warranty is an important consideration. It is a significant investment; one you should expect to protect your investment, property, and tenants for years to come.

What Warranties Are Available?

There are three main types of flat roof warranties available on the market:

  • workmanship;
  • materials-only; and
  • material and workmanship.

A workmanship warranty covers labor and installation. It is an assurance that the roofing contractor will stand by his or her work and repair any mistakes or defects that may arise as a result of their workmanship.

A materials-only warranty is a warranty covering the manufacturer’s materials used to install your roof. It means that if your roof fails because of a shortcoming or malfunction in the manufacturer’s roofing materials, they will cover the cost of replacement. A material-only warranty does not apply to products made by another manufacturer. It also does not cover workmanship defects or wind, hail, and ice damage.

Finally, a materials and workmanship warranty covers materials, labor, and installation. It certifies the installer will follow detailed manufacturer installation instructions and the manufacturer will guarantee their workmanship as a result. It also covers all parts and materials used during the installation.

What Is the Best Warranty?

At Flat Roof Solutions, we specialize in installing single-ply membrane flat roofing solutions. In our experience, customers who get a manufacturer-issued materials and workmanship warranty have the best roofing outcomes. The reason is the manufacturer holds the roofer to a higher installation standard than they may do on their own.

A Flat Roof Solutions roofer installing a Duro-Last single-ply roof membrane | getflatroofing.com

Here’s why that happens.

Manufacturer-Created Installation Specifications

Every roofing manufacturer has drawings of how the components of the roof should be installed. That goes for fastening the deck sheets, flashing curbs and walls, edge termination, and so on. There are drawings and specific guidelines the installer must follow before the manufacturer will issue its warranty.

Roofers that issue their own warranty are not working with a guide. They are free to do less than what a prudent design would call for.

A good example of this is the number and placement of roof fasteners. In the field of a fully adhered roof, you need a minimum of 12 fasteners per 4×8 sheet of polyisocyanurate or ISO. At Flat Roof Solutions, we routinely see installations where the roofer warranted the job and used only 4 or 5 fasteners. Since there was no 3rd-party inspection (like when the manufacturer inspects the roof), and probably no mention of a design spec, they felt free to short the job.

Off-Brand and Cheap Products

When a roofer writes their own warranty, they are free to use any product. Flat Roof Solutions has seen bids where the roofer didn’t even specify a particular manufacturer of a product; they just used generic descriptions like “TPO roof”. This is probably because they don’t want to be locked into using a specific brand or product. They are free to install the cheapest thing available to them.

In most cases, the manufacturer is unaware their product is even being used on a job. They, therefore, do not warranty their product.

Product Consistency

At Flat Roof Solutions, we have seen roof membrane sporadic failure. Some deck sheets wore fine, others are worn completely through. The reason this happens is the roofer mixed and matched different brand products based on what was in his or her warehouse or the supply house. Some of the rolls were high quality, others were not.

A roof built like a chain is only as strong as its weakest link.

Materials and Workmanship Warranty

Installers that work hand in glove with manufacturers and issue a manufacturer’s materials and workmanship warranty can’t play these tricks. They are held to a higher standard in the design details and have to use the same products throughout the job.

Manufacturers usually go through an inspection at the end of the job before the warranty is issued. By choosing to work with a certified installer, you are effectively weeding out low-quality roofers doing a substandard installation and end up with a far better, longer-lasting, and reliable outcome.

Expert Advice

Whether you’re a beginner, need advanced information about flat roofing topics, or a refresher,  this is where you can learn everything you need to know about commercial and industrial flat roofing.

Contact us for more information or pricing.




Jared Van Vranken is Vice President and lead estimator at Flat Roof Solutions in Malvern, PA. Jared has directed the installation, repair, recovery, and replacement of commercial flat roofs for more than a decade at Flat Roof Solutions. He guides clients in selecting the best roofing materials for their needs and budget.

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