How to Know When to Replace a Flat Roof

Replacing a roof is a major endeavor and a big expense, so you don’t want to do it if you don’t have to. But, on the other hand, if you wait too long there can be disastrous consequences, be they major leaks coming down through the roof, damaging equipment, carpet, and furniture, or whether they be the entire roof starting to come apart, with more things falling down through the ceiling than just water.

Either way if you have a flat roof, then a flat roof replacement is inevitable.

How Long Does a Flat Roof Last?

The material that is used in your flat roof will greatly affect flat roof life expectancy. Flat roof materials that are a multi-layer built-up roof that consists of waterproof material, hot tar, and gravel can last a good long while–15 to 20 years. Roofs that are less well built-up, which may be made of 3-5 layers of modified bitumen will last more in the 10-15 year range.

Metal roofs will last longer than tar and gravel roofs–if they’re installed correctly with the appropriate waterproof fasteners and on the appropriate slope.

But no matter the type of roof that you build, there are going to be signs that repair or replacement is needed, whether we’re talking about a commercial building or a residential structure.

Signs Your Flat Roof Needs to Be Replaced

There are many things to take into consideration when it’s time to replace a flat roof, but we’ve narrowed it down to four major factors.

Roof construction on  a flat roof

High Energy Bills

Flat roofs are great for saving energy, and that’s because they’re built with things like TOP, PVC, and EPDM roofing materials. But if you’ve been watching your utility bills and have been noticing that there’s a significant change in the way your building is retaining heat or cold, then looking at commercial flat roofing is a good place to begin an investigation.

A damaged or old flat roof will begin to have its insulation deteriorate, and failing insulation means that your roof is not doing the job it is supposed to do. Keep an eye on the heating and cooling bills, compare them to the same time last year, and see if your flat roof simply isn’t insulating like it used to.

Roof Leaks and Water Damage

This may seem like a no-brainer, but you’d be surprised at how many people ignore a minor leak in the roof–especially in a commercial building. Often, a bucket is just placed under the leak during rainstorms and then, when the sun comes out, the bucket is put away and the leak isn’t thought of again.

Flat roofs have ways of draining, but roof leaks are essential to get on top of quickly. Leaking roofing typically will have water damage throughout, even if it’s only dripping in one spot. In very, very few cases will the dripping spot inside the building be directly underneath the hole in the roof.

In most cases, the water that is seeping through the roof will travel down the lengths of joists and beams, damaging all of them as it works its way down to your ceiling where it eventually comes out. So a small leak may be doing meters and meters of damage to the roof interior even if it just trickles down in one spot.

And we know what a lot of damage means: the flat roof replacement cost will be that much higher

(Want to know if ponding water on a flat roof is normal? Read here.)

The Age of the Roof

Age of the roof, even if you’re not seeing leaks, is still a major factor you need to consider when deciding whether to get roofing contractors up on top looking at it. While some roofs, particularly metal, can last 30 years, most roofs definitely cannot.

In many cases, it costs very little to get a roofing inspector up onto your roof for an estimate. They can tell you what dangers your roof is posing and what you need to be on the watch for. Maybe the solution is easy to install and they can take care of it for little money, but they may also warn you that your roof is in dire need of repair.

Worried that the roofing inspector is going to talk you into unnecessary repairs? That’s why it’s so important to work with scrupulous roofing companies. Make sure to check their reviews and even ask for references. If a roofing company is worth its salt, it’ll have people you can talk to who will give you honest answers to your questions.


The most obvious reason to look into roof repair is that you have visible damage to your roof. If you’ve recently had a storm, an accident, or even just high winds, getting a good look at your roof will let you know whether a tree branch punctured the roofing, whether some of the tar paper was pulled back in the wind, or whether there has simply been too much foot traffic on the roof that has worn an unwanted path.

If you see the damage, call a roofing inspector immediately. It can save you a lot of money in both the short and long term.

For More Information, Contact Colony Roofers

Learn More About Our Flat Roof Replacements