Our Specialty · Seamless Systems
Fiberglass Roofing In Philadelphia
Seamless, walkable, waterproof — with no seams to fail. It’s the work we’re known for, and the reason rowhome roof decks and flat porch roofs across the city come to us first.
Fiberglass Specialists
Duradek Installs
Crack Repair
Free Estimates
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Cracks caught early are usually a repair — not a tear-off.
Free, no-obligation, itemized. We’ll tell you straight what it needs.
Our Specialty
Seamless, Walkable,
Waterproof
Fiberglass roofing is one of the best surfaces you can put on a flat roof or a rooftop deck in Philadelphia — and it’s the work Garrison is known for. Done right, it gives you a seamless, walkable, waterproof surface with no seams to fail. Done wrong, it cracks and leaks, and most people don’t notice until the water’s already inside.
We’ve spent 20-plus years learning the difference, and it’s why fiberglass is our specialty. If you’ve got a rowhome roof deck, a flat porch roof, or a spot where nothing else has held up, fiberglass is worth a serious look.
Liquid-Applied
One Solid Piece
What Fiberglass
Roofing Actually Is
A fiberglass roof is a liquid-applied system. We lay down fiberglass matting, saturate it with resin so it hardens into one solid piece, then finish it with a UV-resistant gel coat that protects the surface and gives it its color and grip.
The result is a single, seamless membrane bonded to your roof deck. No overlapping sheets, no glued seams, no fasteners punching through.
On a flat roof, seams and penetrations are where leaks almost always start — so a system with none of them is a real advantage. It’s also hard enough to walk on and set furniture on.
Not For Every Roof
Where Fiberglass
Roofing Fits
Fiberglass isn’t for every roof, and we’ll tell you when it’s not the right call. But it’s hard to beat in a few spots.
01
Rooftop Decks & Terraces
Waterproof and walkable at once, so you get usable outdoor space over a fully sealed roof.
02
Flat & Low-Slope Roofs
Common on Philadelphia rowhomes, where a seamless surface outlasts seamed membranes.
03
Porch & Balcony Roofs
Smaller surfaces that take foot traffic and need to stay watertight.
04
Complex Shapes
Applied as a liquid, it wraps around drains, corners, and odd angles that sheet materials struggle to seal.
For larger commercial-style flat roofs, a membrane like TPO or EPDM may be the better fit. We install those too — see our flat roofs page. If fiberglass is right for your roof, we’ll say so. If it isn’t, we’ll tell you that too.
The benefit that sells fiberglass is simple: no seams means no seam leaks, the single biggest failure point on a flat roof. It’s tough, waterproof edge to edge, and a well-maintained fiberglass roof deck lasts for decades. But every one of those benefits depends entirely on the install, and fiberglass punishes shortcuts, which brings us to the part most roofers won’t tell you.
The Costly Repair
What Most Roofers Skip
The Fiberglass Problem
Nobody Warns You About
A fiberglass roof usually fails because of tiny hairline cracks in the surface, and by the time anyone notices, it’s an expensive fix.
These cracks are easy to miss. They show up in the gel coat from normal expansion and contraction, a deck that wasn’t prepped right, or a resin layer that was rushed, and they’re often too thin to see unless you know what to look for. But water finds them. It seeps under the membrane and spreads across the deck where you can’t see it, rotting the wood underneath while the surface still looks fine. Left alone, a crack you could have sealed cheaply turns into a full fiberglass roof deck replacement. It’s the most commonly overlooked and costliest repair we get called for.
Here’s the good news most roofers skip: caught in time, a cracked or leaking fiberglass roof usually does not need to be torn off. Some roofers let you believe it does, because a full replacement is a much bigger check. We clean out the damaged area, re-lay fiberglass and resin, and re-coat the surface so it bonds back into one piece, and you keep the roof you have for a fraction of the cost. If the damage has gone too far, we’ll show you why, with photos. That’s the same straight answer we’d want if it were our own roof.
The Vinyl Alternative
Duradek
Not every walkable roof surface has to be poured fiberglass. Duradek is a heavy-duty vinyl membrane built specifically for rooftop decks, and Garrison installs it too. It rolls out as a single waterproof sheet with heat-welded seams in a range of textures and colors, goes down faster than fiberglass, and flexes instead of cracking on a busy deck. Fiberglass gives you a harder, fully custom finish that molds to any shape.
Which one is right depends on your deck and how you use the space — and because we install both, our recommendation isn’t steered by the one thing we happen to sell.
Specialist, Not Occasional
Why Garrison For
Fiberglass Roofing
Plenty of roofers will take a fiberglass job. Far fewer specialize in it.
A true fiberglass specialist — core work for us, not an occasional add-on
GAF Certified Residential Roofing Contractor — held to manufacturer standards on every install
In-house crews, no subcontractors — the people who lay your fiberglass work for Garrison
20+ years across Philadelphia, including the older rowhomes and roof decks where fiberglass gets used most
Certified Spanish-speaking team — so every homeowner gets a clear explanation
Honest, no-obligation assessments — free, itemized estimates on every job
Fiberglass is one specialty among the full range of roofing services we handle — and a big part of why homeowners here call us first.
Recent Fiberglass Roofs
Seamless
Fiberglass Work
Fiberglass and Dec-Tec surfaces on Philadelphia flat roofs, decks and terraces. Tap any photo to open it full size.
Straight Answers
Frequently Asked Questions
What causes cracks in a fiberglass roof?
Hairline cracks are the most common fiberglass failure, and they come from a deck that wasn’t prepped right, normal expansion and contraction, or a resin and gel coat layer applied too thin or rushed. They’re often too fine to see from the ground, but water gets through and spreads under the surface. That’s why catching them early matters — and why the quality of the original install is everything.
How long does a fiberglass roof deck last?
A properly installed and maintained fiberglass roof deck can last for decades. The surface has to be laid correctly from the start, and the gel coat needs periodic recoating as it wears from sun and foot traffic. Skip the maintenance and hairline cracks set in early. Stay on top of it and it’s one of the longest-lasting flat surfaces you can own.
Is Duradek better than traditional fiberglass?
Neither is flat-out better — they’re built for different priorities. Duradek is a vinyl membrane that goes down fast, flexes instead of cracking, and handles high-traffic decks well. Fiberglass gives you a harder, fully custom, seamless surface that molds to any shape. We install both, so we recommend the one that fits your deck rather than the one we’d rather sell.
Can a cracked fiberglass roof be repaired without full replacement?
Most of the time, yes. If the cracks are caught before water has rotted the deck underneath, we clean out the damaged spot, re-lay fiberglass and resin, and re-coat the surface so it seals back into one piece — no tear-off needed. The trouble starts when a crack gets ignored for years and the damage spreads. Get it looked at early and repair is almost always the answer.
Free & No-Obligation
Get Your Free Fiberglass
Roofing Estimate
Thinking about a fiberglass roof deck, or worried about a crack in the one you’ve got? Get a straight answer on whether you’re looking at a quick repair or something bigger.