As solar energy becomes more popular, understanding how to install photovoltaic (PV) systems on different roof types is essential. In Massachusetts, where energy efficiency and renewable solutions are priorities, choosing the right mounting system is critical to ensuring a secure, long-lasting installation that protects your roof.

In this guide, we’ll explore three common roof types—asphalt shingles, metal standing seam, and EPDM rubber roofs—and explain the engineering behind the specific footings required for each.

Types of Roofs Suitable for Solar PV Systems

Asphalt Shingle Roofs

Asphalt shingles are one of the most common residential roofing materials in Massachusetts. They provide durability and affordability, making them ideal for solar PV installations. However, it’s crucial to use the correct mounting system to ensure roof protection and panel stability.

Footing: The IronRidge QuickMount HUG Footing is specifically designed for asphalt shingles and uses innovative technology to secure the solar panels without damaging the roof. Key features of the HUG system include:

Halo UltraGrip™ Seal Technology: The HUG utilizes a unique combination of foam-and-mastic seal that conforms and adheres to the irregularities of the shingle surface, creating a watertight bond. This ensures that even step-downs or gaps up to 1/8" are sealed, providing superior waterproofing.
Multi-Tiered Waterproofing: The cast-aluminum Halo surrounds the UltraGrip base, providing multiple layers of protection against water intrusion. This design eliminates the need for prying shingles or applying additional sealants in most cases.
Rafter and Deck Mounting: The HUG system offers flexibility to mount directly into the roof rafters or the deck.
- When lagging into a rafter, only two RD Structural Screws are required for a secure installation.
- If attaching to the roof deck, up to six screws can be used to distribute the load and ensure stability. The screws are accompanied by an EPDM sealing washer, which adds an extra layer of waterproofing.
Structural Integrity: Tested and rated for 1004 lbs of uplift and 368 lbs of lateral load, the HUG system provides exceptional durability, withstanding severe weather conditions like high winds and heavy snow.

Why it’s important: The HUG system not only accelerates the installation process but also ensures long-term roof protection with minimal hassle. This system has passed both UL 441 Section 27 Rain Test and TAS 100(A)-95 Wind Driven Rain Test, guaranteeing superior performance in harsh climates like Massachusetts.

EPDM Rubber Roofs

EPDM rubber roofs are common on commercial buildings and flat-roofed homes. Their durability makes them ideal for solar PV installations, but they require specialized mounting systems to avoid damaging the roofing membrane.

Footing: The EcoFasten SimpleGrip SQ Footing is designed specifically for low-slope, membrane roofs like EPDM. The system offers a fast, secure, and watertight installation without cutting into the roof. Key features include:

Watertight Technology: The SimpleGrip SQ base is compressed between two layers of adhesive that create a waterproof seal. This system eliminates the need for additional flashing, offering a fast installation while maintaining the roof’s integrity.
Compression Plate with EPDM Grommet: The compression plate ensures the adhesive stays protected and forms a tight seal with the roof membrane. An EPDM grommet adds another layer of waterproofing, making this system highly effective in preventing leaks.
Self-Drilling Screws: The SimpleGrip SQ system uses four self-drilling screws to provide a secure attachment, offering optimal uplift resistance while minimizing installation time.
UV-Resistant Mastic: The mastic used in the system is UV-shielded, preventing degradation from exposure to sunlight and ensuring long-term durability.

Why it’s important: The SimpleGrip SQ system is engineered to install quickly and without penetrating the roof, which is critical for maintaining the watertight properties of EPDM roofs. By avoiding cuts or intrusions into the membrane, the risk of leaks is minimized, ensuring the roof remains protected for the life of the solar PV system.

Metal Standing Seam Roofs

Metal standing seam roofs are popular for their longevity and minimal maintenance, making them an ideal candidate for solar installations. However, the standing seam design requires specialized equipment to ensure the panels are mounted without damaging the metal roof.

Footing: For metal roofs, the S-5! standing seam clamps are the industry standard. These clamps are engineered to attach directly to the raised seams of the metal roof without penetrating the surface.

No drilling or lagging required: Unlike asphalt and EPDM roofs, metal standing seam roofs don’t require screws to penetrate the surface. The clamps grip the raised seams, providing a secure attachment point for the solar panels without compromising the roof’s structural integrity.

Why it’s important: The non-penetrative approach used with standing seam clamps ensures the metal roof remains watertight and undamaged, extending its lifespan. This method of attachment also makes it easier to adjust or remove the solar panels if necessary, without leaving permanent holes or damage in the roof.

Why the Right Footing Matters for Each Roof Type

Selecting the correct footing for each type of roof is crucial for the long-term success of your solar PV installation. The right engineering ensures:

Structural integrity: Proper footings maintain the roof’s structure, ensuring no long-term damage or leaks.
Safety: Securely attaching the solar panels prevents accidents, especially during extreme weather conditions.
Longevity: Using the right footings extends the lifespan of both the solar PV system and the roof, preventing costly repairs or re-installations in the future.

Factors to Consider When Installing Solar PV on Different Roofs

Roof Age & Condition: Before installing solar panels, assess the age and condition of the roof. If it’s nearing the end of its lifespan, replacing the roof before installation may be a wise choice.
Slope & Orientation: The angle and direction of the roof impact solar panel efficiency. South-facing roofs with a moderate slope tend to yield the highest energy output.
Load-Bearing Capacity: Ensure your roof can support the additional weight of the solar panels and footings without compromising its structure.

FAQ Section

Q1: What types of roofs are best for solar PV systems?
Solar PV systems can be installed on many roof types, but the three most common in Massachusetts are asphalt shingles, standing seam metal, and EPDM rubber. Each requires specialized footings to ensure a secure and long-lasting installation.

Q2: Will solar panels damage my roof?
No, when installed correctly with the proper footings, solar panels should not damage your roof. Proper footings are designed to prevent leaks and maintain the structural integrity of the roof.

Q3: How long do solar footings last?
Solar footings are built to last as long as the solar PV system itself—typically 25-30 years. Proper installation ensures the footings provide a secure attachment for the entire lifespan of the system.

Q4: Can solar panels be installed on flat roofs?
Yes, flat roofs, often found with EPDM rubber membranes, are ideal for solar installations. However, proper footings like the SimpleGrip SQ system must be used to ensure a secure, leak-free installation.