Flat Roof Replacement in Miami — It Fails at the Drains, Not the Field
The stain is over the Florida room, or the addition, or the carport: the flat part. That section is almost never leaking in the middle. It is leaking at a drain, a scupper, a wall flashing, or the seam where the flat roof ties into the sloped one. We replace residential low-slope roofs across Miami-Dade and Broward, and we will tell you which of those it is, in writing, before you sign anything.
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Licensed & Insured
The Product Is Named
The Miami-Dade approval for your system, on the proposal, before you sign
Permits Pulled & Closed
Final inspection sign-off in your closeout package
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Water that sits is what shortens a low-slope roof
A flat roof is never truly flat — it is a low-slope roof that is supposed to move water to a drain or a scupper. When it stops doing that, water sits. The code agrees with us about what that costs, and it makes us tell you so in writing: the Owner's Notification you sign with the permit states that ponding “may shorten the life expectancy and performance of the new roofing system” and “should be corrected” (Florida Building Code, Required Owner's Notification for Roofing Considerations). Positive drainage means the roof clears within about 48 hours of rain.
So before we quote, we follow the water: drain and scupper locations, whether the deck has sagged, whether a previous re-roof buried a drain under new layers, and whether the field needs tapered insulation to re-establish slope. If your roof needs the slope corrected, we say so, and price it, rather than lay a new membrane over the same puddle. No membrane brand fixes a roof that does not drain.
What is not a roof, even when a bid says it is?
An underlayment is not a roof. A self-adhered sheet like Polystick XFR is approved as an underlayment and nothing else. Miami-Dade lists it under Category: Roofing, Sub-Category: Underlayment. It may be left exposed as a temporary roof for a limited period and then has to be covered. It is not an approved flat roof covering, and we will not price it as one, whatever else you have been quoted.
A coating is not the same thing as a fluid-applied roof. A roof coating is a maintenance product. In Miami-Dade it is approved under “Cements–Adhesives–Coatings,” and those approvals say on their face that they may not be used as a roof system, so a coating rolled over a failed roof does not reset the clock. That is a different thing from a fluid-applied reinforced roofing system, which is a genuine approved roof covering with its own Miami-Dade system approval and its own wind design pressure. We do not install those on residential flat work, but they exist, and the difference is on the paperwork.
You do not have to take our word for any of it. Take a bid you are holding and ask one question: what is the Miami-Dade product approval for the covering you are installing, and what sub-category is it in? A real flat roof covering has one. An underlayment and a coating are in different categories. Ours goes on the proposal before you are asked to sign anything.
What flat roof systems do you install on a Miami house?
Residential low-slope work at Robson is modified bitumen, TPO, or built-up roofing (BUR). We will tell you which of the three your roof should get before you ask, and we will put the reason in writing next to it. A proposal that just says “new flat roof” is not a proposal.
Most Miami houses with a flat section have it over an addition, a Florida room, a carport, or a flat-and-mansard combination, not over the whole house. That matters, because a small low-slope field tied into a sloped roof lives or dies at the transition detail, and that is the part a cheap bid skips.
We do not install PVC on residential work. It lives on our commercial line. On a small residential field the three systems above give you the same waterproofing with easier repairs and a crew that works with them every week.
Flat Roofing At a Glance
- Systems
- Modified bitumen, TPO, BUR
- Not offered
- PVC (commercial line only)
- Mod-bit build
- SBS base sheet + granule cap (ASTM D6163/D6164)
- Also available
- Cold-applied mod-bit (no torch, no kettle)
- TPO attachment
- Mechanically attached or adhered, heat-welded seams
- Slope correction
- Tapered insulation, priced separately
- Manufacturer warranty (TPO)
- GAF EverGuard 60 mil — 20 yrs, material only
- Workmanship warranty (mod-bit/BUR)
- Robson, 5 years, transferable once
- Workmanship warranty (TPO)
- Robson, 10 years, transferable once
Modified bitumen, TPO or BUR — which is right for a Miami flat roof?
Most Miami flat sections should get modified bitumen. TPO roofing in Miami earns its place on a bigger open field where heat reflection matters, and BUR earns it where a heavy, redundant multi-ply asphalt membrane is the right answer. The deciding factor is almost never the brand. It is how the roof drains today and what the deck looks like once we open it up.
| Modified bitumen | TPO | BUR | |
|---|---|---|---|
| What it is | SBS asphalt membrane — base sheet plus granule-surfaced cap | Single-ply reflective white membrane, heat-welded seams | Multi-ply asphalt and ply-sheet built-up assembly |
| Best for | Small residential fields, additions, tie-ins to sloped roofs | Larger open fields where heat reflection matters | A heavy, redundant membrane, and re-roofs tying into existing hot-applied assemblies |
| Service life we quote (install-dependent, not a warranty) | 15–20 years | 20–25 years | 15–20 years |
| Repairability | Easy — patches bond to the existing membrane | Good — but repairs must be welded, not caulked | Good — plies can be cut in and re-flashed |
| Torch on your house? | Not required — cold-applied option available | No torch, hot-air welded | Hot-applied |
Service-life ranges are the ranges Robson Industrial Group LLC (CGC1541144, CCC1337790) is willing to put in writing on Miami-Dade and Broward installations. They are not manufacturer marketing figures and they are not a warranty term. Slope correction on any of the three is done with tapered insulation, which is an approved component under single-ply, modified bitumen and BUR alike.
How does a residential flat roof replacement work?
We get on the roof
We count the layers already up there, check whether the deck under them is sound, and follow the water: drains, scuppers, every penetration, and the seam where the flat meets the slope. Then the system and the product approval go in writing on the proposal, not decided later on the job.
Permit and tear-off
We pull the permit with the county or city. The old covering comes off down to the bare deck, which is where you find out what you actually bought.
The deck, honestly
On a wood deck, HVHZ code does not allow a new roofing system over sheathing that is not fastened to current code, so where the existing nailing falls short we re-nail the entire deck to current code at no additional charge, and sign the county's roof-decking attachment affidavit. Rotted or delaminated sheathing comes off and gets replaced at $100 per sheet, named on your proposal before you sign, not decided after tear-off. On a concrete deck there is nothing to re-nail, and we tell you that instead of billing you for it.
Anchor sheet, membrane, closeout
On a low-slope roof the county inspects the anchor sheet before it is covered, then inspects again at the end. Cap sheet or membrane goes on, then the parts that actually leak: drains, scuppers, curbs, pipe penetrations and wall flashings. Final inspection, then a documented closeout package.
How the money and the surprises are handled
Payment follows inspections, not promises. And the deposit is the headline. Most homeowners brace for 30–50% down before a contractor touches the roof. Robson’s standard schedule is 10% at signing, 40% when the deck and underlayment pass the dry-in inspection, 40% at in-progress inspection approval or material delivery to the site, and the final 10% at completion. Four milestones, each tied to an inspection or a delivery, not a date on a calendar.
If we find something mid-job — a rotted deck section, a third layer that should not be there — work stops, you get photographs, and nothing continues without your written approval. A surprise on your roof should never become a surprise on your invoice.
We do not tear off more roof in a day than we can dry in. Your roof is never left open to a Miami afternoon storm because the schedule got ahead of the weather.
Choosing a flat roofing company in Miami: what should you check before you hire?
We are not going to be the lowest number on your kitchen table. Almost all of the difference sits in the parts of the job you cannot see from the driveway: the tie-in where the flat section meets the sloped roof, the drains and the scuppers, the deck, and whether the roof is being made to drain or simply re-covered. Those are the same items a low bid leaves out. That is why it is a low bid.
So do not compare the totals. Make every bid, ours included, put these in writing:
- The approved covering by name, with its Miami-Dade product approval and its sub-category. Not “underlayment.” Not “coating.”
- Who pulls the permit, and who closes it.
- What is being done to the drains, the scuppers, and the tie-in to the sloped roof.
- Whether tapered insulation is included, if the roof does not drain today.
- The workmanship warranty and the manufacturer warranty, listed separately.
- The licence number that covers roofing — not just general contracting.
A bid that cannot answer those six is not a price. It is an opening offer.
Residential Flat Roof FAQ
What kind of flat roof do you install on a house?+
Three systems: modified bitumen, TPO, and built-up roofing (BUR). Modified bitumen is the most common choice on a residential flat section: a mechanically fastened SBS base sheet with a granule-surfaced SBS cap sheet (ASTM D6163 glass-reinforced, or D6164 polyester-reinforced), usually with an interply between them. The exact number of plies comes from the Miami-Dade product approval for that assembly, not from a rule of thumb, and it goes in writing on your proposal. Cold-applied versions are available, so there is no torch on your house. TPO is a single-ply reflective membrane with heat-welded seams, better suited to larger open fields. BUR is a multi-ply asphalt assembly, heavy, redundant, and easy to cut in and re-flash. We do not install PVC on residential work.
How long does a flat roof last in Miami?+
The ranges we are willing to quote are 15 to 20 years for modified bitumen and BUR, and 20 to 25 years for TPO. All three are heavily install-dependent, and the biggest single variable is not the membrane. It is drainage. A roof that ponds water will not reach the top of its range no matter whose membrane is on it. Keeping drains and scuppers clear is the cheapest thing a homeowner can do to protect a flat roof. These are quoting ranges based on how we build the assembly, not a warranty term.
Why does my flat roof keep leaking after it was repaired?+
Because the field membrane is rarely what failed. Low-slope roofs leak at the details: drains, scuppers, curbs, pipe penetrations, wall flashings, and the transition where the flat section meets a sloped roof. Sealant smeared over one of those is a temporary fix that hides the actual defect. A durable repair means opening the detail, correcting it, and re-flashing it with materials that belong to the system already on the roof.
Can you just repair part of my flat roof?+
Up to a point. Florida Building Code limits repair, replacement or recover to 25 percent of a roof section in any twelve-month period. Past that, the whole section has to be brought up to current code. There is one important exception: if that roof or roof section was already built or replaced to the 2007 Florida Building Code or later, only the part being worked on has to meet current code, under Florida Statute 553.844(5). We check the permit history before we tell you which one you are in.
Can you install a new flat roof over the old one?+
Sometimes. In Miami-Dade and Broward the code allows one additional roofing system over the original: two total, no more. Before it is allowed, the existing assembly has to pass a moisture survey and an uplift or fastener-withdrawal test, and those results go in with the permit application. If the deck is wet, or the roof already carries two layers, it comes off. We check the layer count and the deck before we quote, because finding a third layer after tear-off starts is how a fixed price turns into a change order.
Is a roof coating the same as a new flat roof?+
No. A roof coating is a maintenance product, approved in Miami-Dade under “Cements–Adhesives–Coatings,” and those approvals state on their face that they may not be used as a roof system. Rolled over a failed roof, a coating hides the failure and resets nothing. That is not the same as a fluid-applied reinforced roofing system, which is a genuine approved roof covering with its own system approval and wind design pressure. We do not install those on residential flat work, but they are real. Neither is an underlayment a roof: a self-adhered sheet such as Polystick XFR is approved as an underlayment only. If a bid you are comparing lists an underlayment or a coating as the roof itself, ask what the approved covering is and what sub-category its approval is in.
Do I need a permit to replace a flat roof on my house?+
Yes. A re-roof in Miami-Dade or Broward is permitted work with inspections along the way. On a low-slope roof the county inspects the anchor sheet before it is covered, and inspects again at the end. On flat sections under 1,500 square feet the building official may authorise the work to continue and require documented evidence instead. We photograph and document either way. We pull the permit and we close it. An open permit is invisible until you try to sell or refinance, and then it is not, so the final sign-off is part of your closeout package, not an afterthought.
How do I check that you are who you say you are?+
Look us up yourself. Both numbers on this page are public record. CGC1541144 is our state Certified General Contractor licence and CCC1337790 is our state Certified Roofing Contractor licence, and the Florida DBPR licence search will show you the status and history of each. Do the same to everyone bidding your roof, and ask specifically for the licence that covers roofing: a general contractor licence by itself is not a roofing licence, and whoever pulls your permit has to hold the right one.
What if the timing is wrong for the money?
Nobody budgets for a flat roof. It shows up with a deadline attached, usually a leak or a letter from an insurer. Ask when we come out. It does not change the price of the work, and it does not change which system we tell you your roof should get. See financing options →
What if you don't need a full replacement?
We would rather repair a detail than sell you a roof you do not need yet. If the field membrane is sound and one flashing failed, we will say so on the same visit. Flat roof repair in Miami is often a one-day detail, not a re-roof.
Just a leak?
Sometimes a flat roof needs one detail opened and re-flashed, not the whole field torn off. We will tell you which on the first visit.
Miami roof leak repair →Is the whole roof going?
If more than a quarter of the roof is coming off in a twelve-month period, Florida code changes what has to be brought up to current standard. Here is what that means.
See roof replacement →Not sure what you have?
Take two photos — the whole roof and the spot that worries you — and send them our way. We will tell you whether you are looking at a repair or a replacement conversation before anyone climbs a ladder.
Call or text (954) 546-4161 →Find Out What Your Flat Roof Actually Needs
We will walk your roof, check where the water is supposed to go and where it is actually going, and give you the system, the drainage fix and the product approval in writing, before anyone quotes you a number. No cost, Miami-Dade and Broward. We answer seven days a week, 8:00 AM to 8:00 PM. Hablamos español.