Commercial roofing materials are not indestructible, so they will eventually have problems. It’s important for business owners to know what problems they should expect so they know how to spot the signs of an issue and when it’s time to contact a professional for help. Here are some of the most common problems that may arise with commercial roofing in Denver:


A commercial roof may develop a leak for a number of reasons. Roofs must be designed with water drainage in mind, meaning the roofing professional who installs your roof must figure out where and how water will drain. If there is no drainage system, water that falls on the roof will have nowhere to go. The longer that it sits on the roof, the more likely it is that the water will seep through the roof’s membrane and start leaking inside your building.

Leaks can also start to form if the roof is starting to wear down because of its age. A commercial roof can last anywhere from 15 to 50 years, depending on the type of roofing material that is used. As you get closer to the end of the roof’s lifespan, the materials may start to deteriorate and leaks may start to form.

If you spot puddles of water inside the building or dark-colored stains on the ceiling, this indicates there is a leak in your roof. Some property owners are able to smell a leak before they see it. If you smell mold but can’t figure out where it’s coming from, this could be a sign that the roof is leaking.

Thermal Shock

One problem that many property owners are unaware of is thermal shock, which is most likely to occur in the beginning of winter when the days are warm and the nights are cold. The roofing system will expand slightly when it is exposed to warm temperatures, and then contract when it is exposed to cold temperatures. Roofing systems that are exposed to both warm and cold temperatures within the same day will expand and contract as the temperatures change throughout the day. But, this puts a lot of stress on the roofing materials, especially if they are already worn down due to their age.

It’s recommended that you look for the signs of thermal shock if the temperatures have been high during the day and low at night. If you see any cracks or buckling in your roof, call a professional for help. You should also pay close attention to areas with flashing, which may become loose after expanding and contracting repeatedly.


As previously mentioned, sitting water can lead to roof leaks. But in some cases, the sitting water may become so heavy that it causes the entire portion of the roof to collapse. “Ponding water,” which is water that sits on a roof for longer than 48 hours, can cause a great deal of damage. Every inch of ponding water on your roof weighs an estimated 5 lbs. per square foot. The heavier the ponding water becomes, the more stress it will put on the roof and the structure of the building, eventually causing the roof to collapse.

This is a much more serious issue than a tiny roof leak, so it’s important for business owners to understand how to spot the signs of this problem. Although the National Roofing Contractors Association defines ponding water as water that has been sitting on a roof for more than 48 hours, sitting water can actually do damage before 48 hours has passed. For this reason, it’s strongly recommended that you work with a roofing professional to ensure there is an effective drainage system put in place so water never sits on you roof. See 10 common commercial roof problems.

Punctures Caused by Foot Traffic

Property owners with single-ply or spray polyurethane foam roofs need to be especially careful to avoid punctures caused by foot traffic. If there are constantly people on your roof performing maintenance checks or repairs, it’s possible that the heavy foot traffic could lead to punctures in the roofing material.

Most roofing professionals know to install extra layers of membrane in areas where there are bound to be a lot of foot traffic. But even if you have these extra membrane layers, it’s still a good idea to restrict access to the roof to cut down on foot traffic. This doesn’t mean you should skip inspections or delay roof repairs, but don’t let anyone on the roof that does not have a valid reason to be there.


Blistering is another common problem that may arise on your commercial roof, although it is typically only found on built-up roofs (BURs). Blisters are pockets of trapped air or moisture that form between layers of the roof’s membranes. As the blisters become larger, they will start to stretch the membrane further and further. Sometimes, the blisters will grow so large that the membrane will crack from the pressure.

Blisters are fairly easy to spot as long as you take the time to glance at your roof once in awhile. A blister will make the surface of your roof appear uneven and lumpy. If you spot blisters on your roof, call a professional even if the blisters appear to be shrinking in size. Blistering is a reoccurring problem that will not go away unless it is fixed by a professional. A roofing professional will most likely need to cut through the layers of membrane until he has reached membrane that has not been stretched out. Then, new layers of membrane will need to be installed to make the roofing system whole and effective again.