1. Station A Knowledge Base
  2. Marketplace
  3. Building and RFP technical questions

Should a roof be replaced before doing a rooftop solar project?

When investigating your rooftop solar options it is best to engage a commercial roofer to get an evaluation of the remaining life left in your roof.

You will want to have your installation and warranty details in hand to help aid you in your decision. The end of the warranty doesn’t mean that it’s the end of the roof. In some cases, you will be in a gray area and have to make a decision based on your specific project goals and economics.   

Roof warranties

Most manufacturers have roofing warranties from 10 years up to 25 years.  However, the longer the warranty the more expensive the cost and installation requirements.  A 20-year manufacturer's No Dollar Limit (NDL) warranty covering both materials and labor is the most common warranty.

Roof Material Lifespans

TPO or Thermoplastic Olefin (20-30 Years) TPO roofs have been known to last 20 to 30 years. These flat roofing systems are common in commercial buildings such as warehouses, shopping malls, and expansive office complexes. With proper maintenance and repairs, a TPO roof can last up to the upper limit of its lifespan.

PVC (15-30 Years) PVC is arguably the most popular flat roof material, thanks to its impressive strength and durability. This commercial roofing system is made of thermoplastic material with heat-welded seams making it extremely sturdy with a minimum breaking point of 300 lbs/inch. However, PVC roofs can be relatively expensive due to their strength and longevity.

Modified Bitumen (10-20 Years) Modified Bitumen is a multi-ply roofing material which requires professional installation for enhanced performance. When properly installed by an experienced roofing contractor, your commercial building can highly benefit from its multi-layer structure. Like EPDM roofing, modified bitumen also absorbs heat quickly. Its estimated lifespan is 10-20 years.

Ethylene Propylene Diene Monomer (EPDM) (20-30 Years) The durable rubber which makes up this roof’s membrane is what gives it a higher lifespan of between 20 to 30 years. It’s a synthetic, industrial-grade material and is remarkably durable and resistant to wear under normal to more intense conditions.

The longevity of your roof is largely dependent on the installation process and regular maintenance.