Rooftop Deck Specialists
Custom Roof Decks In Philadelphia
More living space, a skyline view, somewhere to actually sit outside when you don’t have a backyard. Built right, a rooftop deck pays you back every summer — built wrong, it’s a leak waiting to happen.
20+ Years
Fiberglass & Dec-Tec
Rowhome Experts
Free Assessment
Get A Free Deck Assessment
We’ll tell you which system fits — and which ones you don’t need.
Free, no-obligation, itemized. We’ll tell you straight what it needs.
More Living Space, Skyline View
A Rooftop Deck is a Roof First,
And a Deck Second
A rooftop deck is one of the best things you can add to a Philadelphia rowhome. More living space, a skyline view, somewhere to actually sit outside when you don’t have a backyard. Built right, it’s the kind of upgrade that pays you back every summer.
Built wrong, it’s a leak waiting to happen.
That’s the part most people don’t think about until it’s too late. A roof deck isn’t a patio you set on top of your house — and the difference is whether the waterproofing underneath was done by someone who actually knows roofs. We’ve been the rooftop deck specialist Philadelphia homeowners call for over 20 years, and we build them the way we’d build our own.
Waterproofing First
The Part You Can’t See
A Deck is Only as Good
As the Roof Under It
Here’s the thing a lot of deck builders won’t tell you: the beautiful surface you walk on is the least important part of a rooftop deck. What matters is the waterproofing membrane sealed underneath it — because that’s the only thing standing between the weather and the rooms below.
Get that membrane wrong and it doesn’t matter how good the deck looks. Water will find the gap, and by the time you see a stain on your ceiling the damage has been spreading for months. Fixing it usually means tearing the whole deck back up.
We come to roof decks as roofers, not carpenters who also happen to do decks. The roof gets waterproofed to the same standard as any roof we install — then the deck goes on top of it. That order is why our decks hold up.
Matched To Your Roof
Waterproofing Systems
We Install
There’s no single “best” system for every roof. The right one depends on your roof structure, how the deck will be used, and your budget. We install a broader range than most deck contractors in the area — so we can match the system to your roof instead of selling you the only thing we know how to install.
Fiberglass
A seamless, walkable surface that bonds directly to the deck. Extremely durable, no seams to fail, and it doubles as the finished walking surface. A favorite for rowhome roof decks.
Dec-Tec
A vinyl membrane designed specifically for rooftop decks and terraces. Waterproof, slip-resistant, and finished in a range of looks. One of the strongest deck-specific systems on the market.
TPO
A proven single-ply membrane, welded at the seams for a watertight roof surface underneath a deck frame or pavers.
Rubber With Coatings
A cost-effective waterproofing layer sealed with a coating built to take foot traffic and UV.
Not sure which one fits your project? That’s what the free assessment is for. We’ll look at your roof, talk through how you want to use the space, and tell you honestly which system makes sense — and which ones would just be spending money you don’t need to.
Rowhome Specialists
Fishtown · South Philly · NoLibs
Roof Decks On
Philadelphia Rowhomes
Philadelphia is a rowhome city, and rowhomes are practically made for rooftop decks. Flat roof, no yard, and a view worth having. It’s no surprise roof decks have taken off across Fishtown, South Philly, Northern Liberties, and just about every neighborhood with a flat roofline.
But rowhomes come with their own rules. The roofs are older, they share walls with the houses next door, and the flat surface has to keep draining properly even with a deck sitting on it. We know how these roofs are built, where they tend to fail, and how to add a deck without creating a drainage problem for you or your neighbor.
Common Question
Can You Build a Roof Deck
Over an Existing Flat Roof?
Often, yes — and it’s one of the most common questions we get. If you already have a sound flat roof, a rooftop deck can frequently be built over it, as long as the roof itself is in good enough shape to be the waterproof layer underneath.
The catch is that word “sound.” If your existing flat roof is near the end of its life, building a deck on top of a roof that’s about to fail is a mistake you’ll pay for twice. Before we build anything, we inspect what’s already there. If the roof is good, we build on it. If it needs to be redone first, we’ll tell you that straight — because putting a deck over a failing roof means tearing it all off again in a couple of years.
Sometimes the smart move is a fresh roof installation first, then the deck. We’ll show you what we find and let you decide.
Already Have One?
Rooftop Deck Repair
And Resealing
Already have a roof deck that’s leaking, or one that’s due for maintenance? We handle that too.
Rooftop deck leaks usually trace back to a failed seam, a worn-out coating, or waterproofing that was never done right in the first place. We find the actual source of the leak — not just the spot where it’s dripping inside — and reseal or repair the system so it holds.
If your deck coating is chalking, cracking, or letting water pond where it shouldn’t, it’s worth having looked at before a small failure turns into a ceiling repair.
Why Homeowners Call Us
Why Garrison
For Roof Decks
Rooftop deck specialists — we build decks as roofers first, so the waterproofing is done right
The widest range of deck systems in the area — fiberglass, Dec-Tec, TPO, and rubber with coatings, matched to your roof
GAF Certified Residential Roofing Contractor — the roofing under your deck is done to manufacturer standard
In-house crews, no subcontractors — the people who build your deck work for Garrison
20+ years on Philadelphia rowhomes — we know how to add a deck without creating a drainage problem
Certified Spanish-speaking team and honest, no-obligation assessments on every project
Drag The Handle
Roof Decks,
Before and After
A storm-damaged roof turned into a waterproofed double deck.
Recent Roof Decks
Decks We
Have Built
Wood, composite and Dec-Tec walkable surfaces — built so the deck and the roof under it both last. Tap any photo to open it full size.
Straight Answers
Frequently Asked Questions
What is the best waterproofing system for a rooftop deck?
There isn't one answer that fits every roof. Fiberglass gives you a seamless, walkable surface with no seams to fail. Dec-Tec is a vinyl membrane built specifically for decks and terraces. TPO and rubber-with-coatings are proven, cost-effective options depending on your structure and how the deck will be used. The best system is the one that fits your roof, your usage, and your budget — which is exactly what we sort out during a free assessment.
How often does a roof deck need to be resealed?
It depends on the system and how much wear the deck takes, but every waterproofing system needs attention over time. Coatings wear, seams age, and UV takes its toll. The honest answer is to have it inspected periodically rather than wait for a leak — catching a worn coating early is a maintenance job, while ignoring it can turn into a full deck teardown.
Can a rooftop deck be built over an existing flat roof?
Frequently, yes — if the existing flat roof is in good enough condition to serve as the waterproof layer underneath the deck. If the roof is near the end of its life, it's usually smarter to replace it first, because building a deck over a failing roof means tearing it all back up in a few years. We inspect the existing roof before we build so you're not paying for the same work twice.
What causes rooftop deck leaks?
Almost always a failure in the waterproofing under the deck — a worn or cracked coating, a failed seam, water ponding where it shouldn't drain, or waterproofing that wasn't installed correctly to begin with. Because the leak you see inside is often several feet from where water actually gets in, we track the real source before repairing, then reseal or rebuild the system so it holds.
Free & No-Obligation
Get a Free Roof
Deck Estimate
Thinking about adding a rooftop deck, or dealing with one that’s leaking? Talk to the specialists who treat the roof under your deck as seriously as the deck on top of it.