Flat Roof Replacement and Repair: The Ultimate Guide to Roof Repairs

The Ultimate Guide to Flat Roof Replacement and Repair

HomeThe Ultimate Guide to Flat Roof Replacement and Repair


flat roof replacement gravelI’m sure you’ve heard that the only certainties in life are death and taxes. Well, for those of you that have a flat roof, you know that there are actually three certainties.

Flat roofs leak! End of story. (Thanks for coming; I’ll be here all week. Please tip your waitress.)

Of all the flat roofs in use today, you can bet that around 99% will leak at some point. Which means eventually you’ll have to Google either “flat roof replacement” or “flat roof repair,” while simultaneously popping Excedrin like they were Skittles, in an attempt to rid yourself of your roof-related headache.

All right, enough doddling about. You’ve got a leaky roof to fix. So let’s get to the meat of this already. But first a line from Shakespeare: To replace your flat roof or not to replace your flat roof; that is the question.


Flat Roof Replacement Cost

According to Fixr.com, the national average expense for flat roof replacement is between $4000 and $5000 for a 1200 square foot home.

Of course, this will depend on the materials of your flat roof, and whether or not you do it yourself, or pay someone who specializes in flat roof replacement. And when it comes to doing it yourself, you just have to ask yourself one question: Do I know the difference between a flathead screwdriver and a Phillips-head screwdriver?

Oh, you do? Well then, you should be fine! So let’s skip ahead to the materials, some of which are easier to work with than others.


Flat Roof Replacement: What Materials are Best?


flat roof replacement materialsPVC Single-Ply Membrane

PVC is the most popular material for constructing flat roofs. It’s strong, durable, and usually carriers with it a lifetime warranty. Which could make the decision process a pretty quick and easy exercise.

PVC roofing has seams that are welded together using hot air. However, the seams are quite strong. In fact, they’re even stronger than the material itself.


EPDM Rubber

EPDM stands for Ethylene Propylene Diene Monomer, which no one can say fast 10 times in a row without inducing a stroke. So let’s just call it rubber. Or EPDM.

After PVC, EPDM is the next most popular flat roof replacement material. The seams aren’t as strong, but it’s lower in price. Unless you’re planning on going super thick, as the membrane’s thickness will definitely affect the cost.

Plan on paying somewhere around $2-$3 per square feet, not including professional installation.



I know what you’re thinking, and yes. There are a lot of acronyms in the field of flat roof replacement. But it sure beats having to read something like ethylene propylene diene monomer over and over.

TPO is a mix of rubber, ethylene, propylene, and various fillers. It’s gaining in popularity, likely because it’s more energy efficient than the two other acronyms above.

If you’re torn between PVC and EPDM, perhaps TPO is the way to go. It’s lower in cost like EPDM, and similar in durability to PVC. Making it a candidate for the Best-of-Both-Worlds’ choice.


Modified Bitumen

Modified bitumen is a mix of roofing asphalt and modifiers like fiberglass or polyester fiber matting. It’s a multi-ply roofing material, unlike the others above that are only single-ply.

The multiple layers mean that it’s more durable and more weather resistant. It’s sold in rolls, which makes it sound like it’d be easy to install. (As if!) And you have the added fun of sealing the seams with a torch. Which doesn’t sound easy or safe.

Disclaimer: torch means fire!


BUR (Built Up Roofing)

flat roof replacement specialistBUR basically refers to tar and gravel. It consists of alternating layers of bitumen with layers of gravel or other materials. As you might imagine, this makes BUR roofs quite heavy, which means structural reinforcement may be necessary.

If you’re planning to use your roof as an outdoor living area that will get heavy foot traffic, you may want to consider built up roofing. Otherwise, it may be overkill.


Silicon Spray Coating

The nice thing about silicon spray-on coating is the lack of seams, when compared to membrane roofs. The not-so-nice thing about silicon spray-on coating is the price, as it tends to be … wait for it … through the roof!

(Seriously, please remember to tip your waitress.)


Metal Flat Roof

metal flat roof replacementMetal flat roofs have a long history of success and a long life span, yet are decreasing in popularity. They have traditionally been made from tin or copper, but are generally constructed of aluminum these days.

The substrate can be difficult to work with when installing metal flat roofs. They’re also harder to replace, and can suffer from rust issues, which usually leads to holes. Making this a poor choice in rainier, more humid climates.


Flat Roof Coatings

Flat roof coatings are applied by spraying, and are a more recent development in the flat roof market. Silicon spray coating (listed above) is just one of the different materials used. Other common materials include acrylic and aluminum.

Flat roof coatings are easy to apply, but do require a bit of precision and concentration. You don’t want to miss spots, obviously. But you don’t have seams to worry about, and the material bonds easily around difficult protrusions.

Flat roof coatings look absolutely wonderful when they’re new and shiny. However, don’t expect this to last. The coating remains sticky after installation, so it gets dirty easily, as it grabs hold of dirt, leaves, small birds, and other debris.

Well, maybe not small birds. But if it does, just drape Christmas lights over them come December.


How to Install Flat Roof Roll

flat roof replacement workerFlat roof rolls are another option when it comes to flat roof replacement, and one that you do-it-yourselfers can probably even manage.

Flat roof rolls are kind of like shingles … that roll. They’re less expensive than other options, and can usually be completed in one day. Providing it’s at least reasonably warm, as in 45 degrees or warmer.

Warmer weather means more pliable material. Be sure to clean the roof first, and check for any loose screws or nails. If you use an underlay, this will add more protection, but also more cost and work.

It’s pretty standard stuff, really. You’ll roll out the sheets, apply some cement, nail it down, overlap the seams, and trim away the excess. If you think you may want to go this route, some better instructions for how to install flat roof roll could be useful.


Flat Roof Repair Options

Want to know how the experts repair their roofs. They don’t. They replace them.

Of course it depends on the circumstances. Let’s say you just replaced your flat roof with an even better flat roof, and then out of nowhere a dragon crash landed on it. But just a little bit. Well, in that case …

But usually flat roof repair is a bad option. You see, by the time you notice a leak, it’s likely already done a whole bunch of damage. Plus, if you patch over that area, you may trap moisture inside the roof, which leads to rotting.

Rotting, by the way, is bad!

For older roofs, a repair job is often just a temporary fix. But almost always, it’s a sunken cost. But if you’re still determined to repair your roof instead of replacing it, or if it was just a simple dragon accident, then by all means, continue reading.


Flat Roof Repair: Do it Yourself

flat roof replacement cutting metalSo your roof is leaking. Now what? Well, you could call a professional. But that’s not very DIY of you. So let’s begin by finding that leak, which is sometimes way more difficult than you’d think.

Actually, let’s backtrack. The first thing you’ll want to do is position some buckets around the house and lay a tarp over the area you suspect the leak may be coming from. Buckets go under the leak. Tarp goes over the leak. (Too thorough?)

Repairing your roof, even after you find the leak, depends on the materials your roof is made of, and whether or not you have the skills and tools to do so.

If you are determined to repair your roof, and do it yourself, check out this handy guide on rubber roof repair. Or if you have a tar and gravel roof, this DIY guide should be a handy resource.

Of course, if your roof is still under warranty, well then you’re golden. If not, well …


Flat Roof Leak Repair Cost

flat roof replacement coverSome questions you may want to ask if you’re still leaning towards repair over replacement: How bad is it? What materials do I need? Can I do it myself? That last one is particularly important.

Flat roof leak repair costs run quite a bit higher than flat roof replacement costs. While replacement will run you somewhere between $4.50 and $10 per square foot, repair will usually average between $12 and $20 per square foot.

It seems counterintuitive, but repairing your roof will almost always take longer than replacing it. And labor costs, if not doing it yourself, are a major expense.

The one question you’ll want to ask yourself when deciding if the cost of repair is reasonable is, how old is the roof? If it’s nearing the end of its life expectancy, you may be better off replacing it.


Flat Roof Replacement and Repair Conclusion

If your head isn’t completely scrambled by this point, let’s recap briefly. Flat roof replacement is probably your best bet for older roofs. And you have loads of choices.

Flat roof repair is a decent option for newer roofs that dragons accidentally fly into yet somehow do very little damage.

And doing either of these yourself depends on whether you know the difference between a Phillips-head screwdriver and a flathead screwdriver. The end … of your leaky roof!

Even if you know a little about roof or construction work, you may want to call the experts at Chief Roofing, Inc. Your roof is a major component in the value and safety of your home. Chief Roofing are professional roofers who treat your home as if it was their own. Call today.


Chief Roofing 919-732-5028

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