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Why Seattle’s Summer Can Be Tough on Commercial Roofs

While it may not reach the sweltering highs of southern states, Seattle's summer weather is deceptively harsh on roofing systems. UV radiation, thermal cycling, and membrane shrinkage are all factors that can cause premature wear—and lead to expensive repairs if ignored.

 

1. UV Degradation

In summer, UV rays beat down on your roof for up to 16 hours a day. Over time, this exposure can cause roofing membranes—like TPO, EPDM, and PVC—to dry out, fade, and become brittle. This degradation compromises their flexibility and waterproofing capability. Even ballast and gravel-covered roofs aren’t immune, as underlying membranes can still deteriorate due to heat retention and reflected UV light.

Additionally, wildfire smoke—a growing concern in the PNW—can trap heat and UV rays in the atmosphere, amplifying their effect on exposed roof surfaces. UV damage often appears as discoloration, cracking, and chalking of the membrane. Left unchecked, this can eventually lead to punctures, splits, and interior leaks.

What You Can Do:
Invest in a reflective roof coating designed to block harmful UV rays and reduce surface temperatures by up to 30%. These coatings can significantly extend the life of your roof by creating a protective barrier against solar radiation. At Axiom D7, we use high-performance products that are ideal for Seattle’s climate, offering both energy efficiency and superior UV protection.

 

2. Thermal Expansion and Contraction

Seattle summers often bring wide temperature swings—from cool 50°F mornings to 85°F+ afternoons. This daily fluctuation causes Seattle roofing materials to expand and contract continuously, which can stress joints, fasteners, and flashings. Over time, this movement weakens seals, separates seams, and even cracks the substrate below.

Metal roofs are especially vulnerable to this effect, but even flexible membranes like EPDM can suffer if not properly maintained. Expansion gaps may grow, and flashing details around HVAC units or skylights can loosen—opening the door to future water infiltration once the rainy season returns.

What You Can Do:
Regular commercial roof maintenance inspections during the warmer months are essential. At Axiom D7, we inspect for signs of movement-related wear, including splits, seam separation, and flashing uplift. We’ll reinforce critical areas with flexible sealants, reattach fasteners, and install expansion joints if needed to accommodate movement. Our proactive approach keeps your roof watertight year-round.

 

3. Surface Dry-Out and Membrane Shrinkage

Dry air and high sun exposure can cause single-ply membranes like EPDM and TPO to shrink over time. This happens as plasticizers and oils within the material begin to evaporate—particularly on older roofs that haven’t received proper care. As the membrane contracts, it pulls away from edges, corners, and penetrations, potentially exposing the insulation or deck below.

Membrane shrinkage is particularly problematic in roofs with poor anchoring or insufficient detailing. It often manifests in wrinkling, open seams, or lifted flashings—issues that may not be visible from the ground but can lead to significant water damage come fall.

What You Can Do:
To combat shrinkage, we recommend applying elastomeric roof coatings or re-tensioning the membrane where possible. These coatings form a flexible, seamless layer over the roof, protecting it from sun damage while preserving pliability. Axiom D7’s roofing experts can assess your current membrane’s condition and advise whether a restorative coating or localized repair is the right choice.

 

Summer Roof Maintenance Checklist for Seattle Businesses

To prepare your commercial roof for summer and avoid costly surprises, here are key steps every Seattle building owner should take:

• Schedule a mid-summer roof inspection to catch small issues before they grow.
• Clear debris from drains, scuppers, and gutters—pollen and spring debris can block drainage even in dry months.
• Check all penetrations (vents, skylights, HVAC) for sealant degradation.
• Apply or reapply reflective or elastomeric coatings for UV and thermal protection.
• Ensure rooftop equipment is secure to prevent damage during thermal expansion.

 

Why Choose Axiom D7 for Your Seattle Commercial Roofing Needs?

As a trusted Seattle commercial roofing contractor, Axiom D7 brings local expertise and proven solutions to every project. We understand how seasonal transitions—from wet winters to dry summers—impact roofing systems across the Puget Sound.

Here’s what sets us apart:

• Seattle-specific knowledge: We know how to build and maintain roofs that withstand the city’s unique climate patterns.
• Comprehensive services: From inspections to emergency repairs, coatings, and full replacements—we do it all.
• Preventative maintenance programs: Save money over time with customized seasonal care plans.

 

Ready for a Dry Season Check-Up?

Don’t wait until damage is visible to take action. Contact Axiom D7 today for a summer-ready commercial roof inspection. We’ll help you extend the life of your roof, improve energy efficiency, and avoid mid-season surprises.