Key Takeaways
- Foam roofing eliminates water leak challenges while the installation of solar panels on a flat roof.
- Most flat-roof solar systems use ballasted racking, reducing the need for roof penetrations and lowering leak risk.
- Spray polyurethane foam (SPF) adds insulation while solar panels reduce heat gain through shading.
- Coordinating roof work and solar installation at the same time can save approx 200$/panel in future labor costs. (Source)
- For homeowners considering an Eichler solar installation, foam roofing can help address common flat-roof challenges.
A surprising amount of homeowners put in solar panels on their flat roofs and discover later their roofs need repairs after only a few years. Then the real cost comes in to remove the whole system, repair the roof, replace the whole system.
We have seen this happen more than a couple of times.
If you are looking to put solar panels on a home that you have or if you are looking to do an Eichler solar installation, putting solar panels on a foam roof is one of the smartest things you can do. If done right, both systems work together very well.
Why Flat Roof Solar Panels Work So Well
Many homeowners assume solar performs best on a pitched roof. Not necessarily.
Flat roofs offer flexibility. Installers can position panels at the ideal angle instead of being locked into the roof’s existing slope.
Most flat-roof systems use tilt racks between 10° and 15°. That angle helps:
- Improve solar production
- Promote water runoff
- Reduce dirt buildup
- Limit wind uplift
For homes with large, unobstructed roof areas, this setup often creates more usable solar space than a traditional roof.
The Foam Roofing Advantage
The biggest concern with flat roof solar panels isn’t usually the panels themselves.
It’s water.
Proving the truth of every roof penetration is its potential to create a leak; traditional roofing systems often have extra flashing and waterproofing around their penetrations that, over time, can create headaches when trying to maintain these areas.
Foam roofing changes the equation.
Spray Polyurethane Foam creates a seamless cut to the roof deck with no seams or exposed joints. This makes a huge difference in the simplicity of maintenance for the homeowner. For example, one Bay Area-based homeowner Dura Foam assisted in 2022 installed a new SPF roof and a 9.2 kW solar array, thereby avoiding having to replace the entire roof some four years after installation.
The result? Thousands saved and zero disruption to solar production.
Why Eichler Homes Benefit from This Combination
Eichler homes present unique opportunities and challenges.
Eichler homes all have long, horizontal roofs that are perfect for solar systems; however, many of the original roofs installed decades ago do not meet current insulation standards. Foam roofing is ideal for these homes because of its superior insulative properties.
A fully installed SPF roof will give a home approximately R6-R7 insulation per inch. This extra thermal performance allows for less cooling from the air conditioning when the solar system is being used to generate electricity (that can then be sent back to the grid).
It’s a double win.
For Eichler homeowners with an existing solar panel installation, adding insulation to the roof prior to having the panels installed would provide better energy efficiency and longevity of the roof and significantly lower future maintenance costs.
If you are an Eichler homeowner, keep in mind the ‘foam-first then solar’ checklist.
Conclusion
The foam roofing serves as a long-lasting, well-insulated platform. The solar panels provide shade to the roof surface and supply clean electricity. When combined they contribute to a building envelope that is more efficient than either product working alone, leading to fewer expensive future repairs.
If you are considering the installation of solar on your Eichler or flat-roofed home, it is important to first assess the condition of your roof before proceeding with the solar system installation. This step can help ensure that your new solar system will provide you with 25 years of use without costly surprises along the way.
FAQs (Frequently-Asked Questions)
Q1. How long does a foam roof last under solar panels?
Ans. An SPF coated roof can easily last 50 years given it is maintained and recoated every 5 to 10 years.
Q2. What is the best tilt angle for flat roof solar panels?
Ans. 10° to 15° is the ideal angle when installing solar panels on a flat roof.
Q3. Can I put solar panels on a foam roof?
Ans. Yes, you can install solar panels on a foam roof. Also, it is highly recommended that you combine both to cut costs
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