If your home has a flat roof and it needs replacement, you have a few options. You could go with a built-up roof (BUR), a membrane roof like EPDM, TPO, or PVC, or a modified-bitumen roof. Each type has its advantages, but let’s look at one type of modified-bitumen roof that’s been popular for years: the torch-down roof. This type of flat roof system offers excellent waterproofness, which obviously is a great quality here in Florida. It’s also fairly easy to repair if a leak is detected. And the cost is competitive with other options. So what’s the cost for a torch-down roof?
Why Choose A Torch-Down Roof?
First, we can say this method is proven in the real world. With a torch-down roof, thousands of these roofs have been installed over decades and they work. The technology is simple and the cost is competitive. In Florida, this type of roof should last about 20 years when installed by a professional crew.
The rolled asphalt roofing material is the basic product. It typically has a polyester mat or a similar material as the structure, with an asphalt coating for the waterproofing material. The crew installs it by unrolling the the product slowly while heating the underside, the asphalt side, with a torch. Yes, that’s an open flame, and it is somewhat dangerous, which is why it’s a good idea to have first-rate professional roofers install a torch-down roof. It’s also a good idea to install this roof over rigid insulation to keep the blazing Florida sun from heating up your home in the summertime.
The Installation Method
Here’s how it works: the crew slowly unrolls each roll of material, melting the underside and adhering it to the surface below, making a watertight seal. The seams of each roll overlap by a couple inches as well, also making a watertight seal side to side. Around penetrations like pipes and skylights, the crew fits boots and sealant. You can opt for two layers over the entire roof and call it done, but three layers is better. With three layers, the top layer is the cap sheet. This layer will usually have a granulated finish that improves UV resistance and overall durability. The cap sheet can also have “cool roof” properties, which are a no-brainer in Florida. A cool roof is basically ceramic granules that reflect the sun’s heat, rather than letting it radiate into your home, jacking up your AC costs.
WHAT’S THE COST FOR A TORCH-DOWN ROOF?
A standard range for a torch-down roof in Florida is about $400–$550/square. Roofers quote roofing jobs by the square FYI, which is 100 square feet. You’ll usually see roofing materials priced by the square as well. A 2000-square-foot home with a flat roof will therefore require at least 20 squares of roofing material, and 21 squares is safer. So that gives you a range of $8400–$11,550 for materials, installed. You may also see some other costs like tear off of the existing roof, materials like boots and flashing, and any repairs that must be made to the decking, for example, and waste hauling.
A torch-down roof installation is, in comparison to a shingled roof job, a fairly slow affair. There’s only so fast you can go with the torch. That’s just the way it is, but it gets done.
Other Options: Built-Up Roofs
Just so you know, let’s review the options to a torch-down modified bitumen roof. First, how does a torch-down roof compare with a built-up (BUR)? If your home already has a built-up roof, you could consider getting another. A BUR uses multiple layers of asphalt-soaked roofing felt topped with gravel, so it’s a very heavy roof. If your home doesn’t have this roof in place already, there’s really no reason to beef up the framing to handle all that weight. It would require spending a lot of money for no real advantage.
That said, if that’s what you have now, you can plan on spending roughly the same as for a torch-down roof. It might last a couple of years longer than a torch-down roof, and the installation process will be somewhat more smelly and toxic from the hot asphalt getting mopped on.
Membrane Roofs: Another Option
A membrane roof is a better choice than a built-up roof. It’s light in weight and you have three options that give you a range in price in longevity. EPDM is the cheapest and shortest lived. At $450–$500 per square installed, it’s cost competitive with a torch-down roof, but you can expect more like a 10-15 year lifespan. If you plan to be in your home for an indefinite length of time, that doesn’t seem like money well spend. For just a bit more money, you can get a better roof with TPO.
Going to TPO, which is our membrane of choice, you’ll pay $550–600 per square installed. TPO is a 15–25 year roof in Florida, which is why we go this route. You get many more years of service for basically the same installation cost, so TPO is a much better value than EPDM. We think TPO really hits the sweet spot on durability and value. That’s one of the reasons why it has become so popular in the marketplace.
PVC is the most expensive of the typical membrane roof systems. It costs about $650–800 per square installed and should last 15–30 years. It might be better than TPO, and it might last longer in some cases, but that’s not cut and dried in every case. We think TPO comes out ahead as the best value when installed by a top-notch crew, in terms of the cost for the material vs the lifespan.
We’re Here When You Need Us
If you’d like to talk about replacing your flat roof, give us a call at 813-373-9088. Our team has more than 40 years of experience in roofing. You can also use this form and ask us, “What’s the cost for a flat roof?” and we will contact you.