Commercial Flat Roof Waterproofing

Save on AC Costs & Extend Your Roof's Life

Seals & waterproofs to stop leaks
Reflects UV rays to prevent heat damage
Prevents cracks & peeling with flexibility
Cuts maintenance costs & avoids costly repairs
Boosts energy efficiency by keeping buildings cooler

Before Waterproofing

Before applying any waterproofing system, the commercial flat roof must be thoroughly cleaned to remove dirt, debris, and existing loose materials, following the specific manufacturer's surface preparation guidelines. Any cracks, blisters, or damaged areas should be repaired and fully cured to ensure proper adhesion and long-term performance of the waterproofing membrane or coating.

After Waterproofing

Grenier Construction provides expert waterproofing solutions for existing commercial flat roofs throughout Los Angeles, helping extend roof life and prevent costly water damage. Our advanced coatings and membrane systems not only stop leaks but also reflect sunlight, reducing heat absorption and lowering cooling costs year-round. In addition to waterproofing, we offer general roof repairs to keep your building energy-efficient, weather-resistant, and up to code.

Residential Waterproofing in Pasadena

Prevent Costly Water Damage In Your Home

At Grenier Construction, we have experience repairing existing flat roof's and Waterproofing. Our clients built a room addition to their house some time ago. They were experiencing pooling around their drain, causing leaks into the home. After careful evaluation, we removed and replaced the drain with a bigger 6" x 8" due to the dense leaves causing clogging. We also added new roof flashing and re-painted the existing ones for a seamless look.

Overview of a Job Well Done

Completed Residential Waterproofing

Source of Roof Leak

As shown in the video, this roof drain had been previously "repaired," but the seams were found to be cracked and lifting allowing for water intrusion. When surrounding foliage clogged the drain, water began to pool on the roof surface. The standing water eventually penetrated the building envelope, traveling down the wall and causing swelling and damage to the recently installed hardwood flooring.

Upgraded Drain

We added a bigger drain to accommodate the foliage in the area to pass through the new drain without obstruction. A waterproof membrane was added to the entire area where pooling previously occurred. New flat roofing lay on top to match the existing roof. Then the waterproofing system was applied to the entire roof.