If you have a flat or low-slope roof covered in rubber or single-ply membrane, you may have heard that solar is complicated on that type of surface, or simply not worth the effort. We often hear this from homeowners with flat-roof additions and garages and from commercial building owners with large membrane-covered warehouses and retail spaces. The concern is understandable. Membrane roofs require a different installation approach than standard shingle or metal roofs, and not every solar installer has experience with them.
The reality is that membrane roofs are among the most solar-friendly surfaces available. The flat or low-slope profile gives you unobstructed space, freedom to orient panels at the ideal angle for Michigan’s sun, and easier access for both installation and long-term maintenance. The question is not whether solar works on a membrane roof – it’s is how it gets done correctly: protecting the membrane, accounting for Michigan’s climate, and making sure your roof and your solar system hold up together for decades.
Key Points
- Solar panels can be installed on EPDM, TPO, PVC, and modified bitumen membrane roofs
- The mounting method depends on your membrane type, roof construction, and structural capacity
- Protecting the membrane’s waterproofing integrity is the central concern throughout installation
- Michigan snow load, freeze-thaw cycles, and wind uplift add structural considerations that a generic installer may not account for
- Roof age and condition should be evaluated before installation begins — if your membrane is near end of life, re-roofing first is the smarter move
- Strawberry Solar coordinates the full installation process, including any roofing contractor involvement and all permitting
What Is a Membrane Roof?
A membrane roof is any flat or low-slope roof covered by a continuous waterproof membrane rather than overlapping shingles or standing seam metal panels. Instead of relying on slope to shed water, membrane roofs use a single unbroken layer of material to keep water out. That design makes them common on commercial buildings throughout Michigan: warehouses, office buildings, retail centers, restaurants, and industrial facilities. They also appear on residential properties more often than people realize, covering flat-roof additions, attached garages, lower sections of split-level homes, and the occasional full flat-roof home.
The Main Types of Membrane Roofing in Michigan
Understanding which type of membrane you have matters because each one has different properties that affect how solar is mounted and how the waterproofing is protected during installation.
EPDM
EPDM is a synthetic rubber membrane, typically black, and one of the most common membrane types on Michigan commercial and residential flat roofs. It is highly flexible, which makes it well-suited to Michigan’s freeze-thaw cycles. A properly installed EPDM roof can last 25 to 40 years. Because it is a rubber material, it requires rubber-compatible adhesives when mounting hardware is bonded to its surface.
TPO
TPO is a single-ply thermoplastic membrane, almost always white. The reflective surface reduces cooling loads in summer, and the heat-welded seams create strong, watertight bonds. TPO has become the most widely used commercial membrane type in recent years. For solar installations, TPO is particularly well-suited because mounting pads can be heat-welded directly to the membrane surface without penetrating it.
PVC
PVC is a polyvinyl chloride membrane known for its chemical resistance and fire performance. It is common on restaurants, industrial facilities, and buildings where chemical exposure is a concern. Like TPO, PVC can accept heat-welded mounting pads, making it compatible with non-penetrating solar installation methods.
Modified Bitumen
Modified bitumen is an asphalt-based membrane system, typically installed in multiple layers. It is older technology and still common in Michigan’s existing commercial building stock. Solar can be installed on modified bitumen roofs, though the installation approach requires more care around surface protection and adhesive compatibility.
Knowing which membrane you have is the first step in determining how your solar system will be mounted.
Can Solar Panels Be Installed on a Membrane Roof?
Yes, and in several ways a membrane roof is actually a better surface for solar than a traditional pitched roof. Here’s why:
On a pitched shingle or metal roof, the angle of the panels is largely determined by the roof itself. On a flat membrane roof, panels are mounted on racking that can be set at whatever tilt angle produces the best output for your location. In Michigan, where winter sun angles are low and grey skies are common from November through March, the ability to optimize panel tilt is a meaningful advantage. You are not locked into a south-facing pitch that may or may not match ideal production angles.
Flat membrane roofs also offer large, unobstructed surface areas, which is particularly valuable for commercial buildings trying to offset significant electricity loads. There are no dormers, no valleys, no multiple roof planes to work around. And because the surface is accessible and low-slope, both installation and future maintenance are easier and safer than working on a steep pitched roof.
The central concern with membrane roof solar is protecting the membrane. A membrane roof’s waterproofing depends on the integrity of a continuous surface. Any mounting approach that punctures or damages that surface without proper sealing creates a potential leak point. Getting this right is what separates a well-executed membrane roof solar installation from one that causes problems years later.
Your Roof Is Ready. Let’s Talk Solar.
Strawberry Solar installs on EPDM, TPO, PVC, and modified bitumen roofs across Michigan. Get a free quote and we’ll assess your roof as part of the process.
Get a QuoteHow Solar Is Mounted on a Membrane Roof
The mounting method is what makes membrane roof solar meaningfully different from a shingle or metal roof installation. There are three primary approaches, and the right one depends on your membrane type, your roof’s structural capacity, and the specific conditions of your building.
Ballasted Mounting
Ballasted mounting is the most common approach on flat membrane roofs, and for good reason. In a ballasted system, the solar racking sits on weighted bases, typically concrete blocks or pavers, that hold the array in place through sheer mass. No fasteners penetrate the membrane. The waterproofing layer is left completely intact.
Because there are no penetrations, ballasted systems are the lowest-risk option for membrane integrity. They are also the only approach that does not require coordination with a roofing contractor, since the membrane is never touched. The installer works entirely on top of the surface using protective pads between the ballast and the membrane to prevent abrasion.
The tradeoff is weight. Concrete ballast adds significant load to the roof structure, and that load has to be evaluated against the building’s structural capacity. In Michigan, that calculation also has to account for snow load. A roof that carries ballasted solar racking and a heavy Michigan snowfall at the same time is carrying a combined load that must be within the building’s engineered limits. For most well-constructed commercial buildings this is not a barrier, but it requires verification.
Wind uplift also factors into ballasted system design. The Great Lakes region produces strong and variable winds, and the ballast weight must be calculated specifically for local wind conditions, not a national average. Taller buildings and exposed sites require more ballast to resist uplift forces.
While we have done other mounting methods and can service those installations when required, Strawberry Solar primarily works with ballasted mount systems on membrane roofs.
Adhesive and Heat-Welded Mounting
For buildings where added structural load is a concern, or where the membrane type makes it possible, adhesive and heat-welded mounting systems offer a lighter alternative that still avoids penetrating the membrane.
On TPO and PVC roofs, mounting pads can be heat-welded directly to the membrane surface using the same technique used to seal the membrane seams. This creates a permanent, watertight bond between the pad and the membrane. Racking rails attach to these pads, and panels mount to the rails. The membrane is bonded to, not punctured, and the waterproofing stays intact.
On EPDM roofs, heat welding is not an option because EPDM is a thermoset rubber rather than a thermoplastic. Instead, structural adhesives specifically formulated for rubber membrane compatibility are used to bond mounting hardware to the surface. The adhesive must maintain flexibility through Michigan’s temperature swings and freeze-thaw cycles, and surface preparation has to be done correctly for the bond to hold long-term.
Adhesive and heat-welded systems are lighter than ballasted systems, which makes them a good fit for buildings with limited structural reserve. They do require more membrane-specific expertise than ballasted systems, and the chemistry of the adhesive or weld must match the membrane material exactly.
Mechanically Fixed Mounting
Mechanically fixed systems anchor the solar racking directly to the roof deck or structural framing through fasteners that penetrate the membrane. This approach offers the highest wind uplift resistance of the three methods, which makes it the right choice for taller buildings, high-wind locations, or large commercial arrays where ballasted systems would require an impractical amount of weight.
The tradeoff is that every penetration point is a potential leak if not handled correctly. Each fastener location requires proper flashing and sealing, coordinated with the membrane manufacturer’s approved details. This is work that requires active involvement from a roofing contractor alongside the solar installer. Done correctly, mechanically fixed systems are fully watertight and long-lasting. Done carelessly, they create the exact problem a membrane roof owner is trying to avoid.
Before You Install: What to Evaluate on a Membrane Roof
Not every membrane roof is ready for solar on the day you decide to go solar. Three factors should be assessed before installation begins.
Roof Age and Condition
This is the most important factor. Installing solar on a membrane roof that is near the end of its useful life creates a costly problem down the road: when the membrane needs replacing, the solar panels have to come off first, and then go back on after the new membrane is installed. That is an avoidable expense if you plan ahead.
As a general guideline, if your membrane has less than 10 years of remaining life, re-roofing before solar installation is usually the smarter financial decision. If you are unsure about remaining membrane life, look for visible signs of wear: cracking, seam separations, blistering, persistent ponding water, or areas that have been patched multiple times. Strawberry Solar evaluates roof condition as part of the site assessment and will flag any concerns before the project moves forward.
Structural Capacity
Solar panels, racking hardware, and ballast materials add load to the roof structure. The amount varies by system type but typically ranges from 2 to 12 pounds per square foot. In Michigan, that load has to be evaluated alongside anticipated snow accumulation. The two combined must fall within the building’s structural design capacity.
For most commercial projects, a structural engineer reviews the roof and signs off on the design before installation begins. If any reinforcement is needed, the engineer identifies it and we work through next steps with you.
Drainage
Flat membrane roofs are designed with specific drainage patterns, and solar panel layout has to work around them. Racking systems and panel arrays can block roof drains or scuppers if placed without attention to water flow, and standing water under or around mounting hardware accelerates membrane wear. We design panel placement to preserve proper drainage across the full roof surface.
Michigan-Specific Considerations for Membrane Roof Solar
A membrane roof solar installation in Michigan involves considerations that do not apply in warmer, drier climates. Here is what makes this state different.
Snow load: Michigan building code requires that roof structures be evaluated for the combined weight of any added load and anticipated snow accumulation. Membrane roofs are already designed to carry snow, but adding solar panels and ballast changes the calculation. This evaluation is standard practice for Strawberry Solar on every membrane roof project.
Freeze-thaw cycling: Michigan goes through repeated freeze-thaw cycles through the fall, winter, and spring. These cycles put stress on adhesive bonds and membrane seams. Adhesive mounting systems need to use materials rated for sub-zero temperatures and repeated thermal movement. Strawberry Solar specifies materials appropriate for Michigan conditions.
Wind uplift: We live in a region where weather produces strong wind events that can arrive from multiple directions. Ballast weight calculations and mechanical attachment designs for Michigan projects need to reflect local wind uplift requirements. A system engineered to national defaults may be undersized for a lakeside commercial building in western Michigan.
Panel tilt and winter output: Michigan’s low winter sun angle means a well-designed tilt can meaningfully improve output during the months when the sun stays low in the sky. We factor this into system design for every flat or low-slope roof project.
Permitting: Permit requirements vary by municipality across Michigan. What applies in Detroit is different from what applies in Grand Rapids or Traverse City. Strawberry Solar handles all permitting on behalf of the customer, regardless of which area the project falls in.
The Role of the Solar Installer and the Roofing Contractor
Membrane roof solar is one of the few installation types where the line between solar work and roofing work can overlap. Understanding who does what helps set the right expectations going in.
For ballasted and adhesive systems, the solar installer typically handles the full installation without needing a roofing contractor on site. The membrane is not penetrated, so there is no roofing work to coordinate in the traditional sense. The installer works from the surface using manufacturer-approved pads and hardware.
For mechanically fixed systems, a roofing contractor needs to be involved to flash and seal every penetration point according to the membrane manufacturer’s specifications. This is not optional work. Unsealed penetrations on a membrane roof will eventually leak, and that damage may void the membrane warranty.
Strawberry Solar manages this coordination directly. If your project requires roofing contractor involvement, we handle the scheduling and coordination so the solar and roofing work proceed together as a single project. You work with one team and we keep things clear and easy to follow. Our residential solar installation and commercial solar installation services both include this coordination as part of the process.
One Team Handles Everything.
From structural assessment to permits to roofing coordination, Strawberry Solar manages the full process on membrane roof projects. No juggling contractors.
Get a QuoteHow Long Do Solar Panels Last on a Membrane Roof?
The solar panels themselves last 25 to 30 years regardless of what type of roof they sit on. Panel lifespan is not affected by the membrane below. What matters is matching the solar system’s lifespan to the remaining life of the membrane so you are not caught pulling panels off mid-system-life for an unplanned re-roof.
Here is how the typical membrane lifespans stack up:
- EPDM roofs, properly installed and maintained, last 25 to 40 years.
- TPO roofs typically last 15 to 25 years. PVC roofs generally last 20 to 30 years.
- Modified bitumen systems typically run 15 to 20 years.
If you install solar on a 10-year-old TPO roof with a 20-year lifespan, plan for panel removal and reinstallation around year 10 of your solar system’s life. That is a manageable cost if you budget for it and a frustrating surprise if you do not. Strawberry Solar factors membrane age into every system design conversation and can advise on timing relative to your roof’s lifecycle. For more on panel lifespan and what to expect over time, see how long do solar panels last.
Frequently Asked Questions
It depends on the mounting method and your membrane manufacturer’s requirements. Ballasted systems, which do not contact or penetrate the membrane beyond protective pads, generally preserve the warranty. Adhesive and heat-welded systems need to use manufacturer-approved materials and techniques. Any penetrations in a mechanically fixed system must be flashed and sealed according to manufacturer specifications. Strawberry Solar works within these requirements on every project.
Yes, as long as the membrane has sufficient remaining life and is structurally sound. We assess this during the site visit. If the membrane is too far along in its lifecycle, we will tell you, and we can help you think through the timing of a re-roof alongside your solar project.
For most commercial projects, yes. The engineer evaluates whether the roof structure can carry the combined load of the solar system, racking, ballast, and Michigan snow accumulation. Strawberry Solar coordinates the engineering assessment as part of the project.
TPO is one of the most solar-compatible membrane types available. Heat-welded mounting pads bond directly to the TPO surface without penetrating it, creating a strong, watertight attachment point. If your commercial building has a TPO roof and adequate structural capacity, it is a strong candidate for solar.
Snow load is factored into the structural assessment for every Michigan membrane roof project. On the output side, panels on a flat membrane roof can be tilted to a steeper angle than a typical pitched roof allows, which improves winter production and helps snow clear from the panel surface more quickly.
Membrane Roofs and Solar Work Well Together in Michigan
A membrane roof is not a barrier to going solar. For many Michigan homeowners and commercial building owners, it is actually an advantage. What it requires is an installer who understands the membrane, knows how to protect it throughout the process, and accounts for the specific demands of Michigan’s climate.
Our team has designed and installed solar systems on EPDM, TPO, and PVC roofs across Michigan. We assess the membrane, evaluate the structure, handle the permitting, and coordinate any roofing involvement the project requires. If you are considering solar on a flat or low-slope roof, the best starting point is a conversation with someone who has done it.
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