Emergency Service

Roof Collapse

The building was a large strip mall we had reroofed about 10 years earlier with Firestone APP 180 modified bitumen. The specific store location where the collapse occurred was a high profile women’s apparel outlet.

We had just received 6-10 inches of wet snow that mid February day, snow that had fallen on top of 4-6 inches from a few days earlier. The snowstorm turned to freezing snow and finally all rain at the end. The recipe was perfect for creating excessive weight on area roofs.

Those inside the store that morning said they heard a very loud boom, felt the store shake, saw the ceiling collapse slightly, and then the lights went out. The roof had partially collapsed and the ceiling with it. Needless to say the store was immediately and voluntarily evacuated. The store personnel then called 911 which resulted in the fire department coming to assess the situation.

The rest of the surrounding stores within this common-roof strip mall were also told to evacuate. Although the damage seemed far from their locations, the reality was that the common nature of the roof put all the stores in jeopardy. After officially condemning most of the building the Fire Marshall quickly called the building manager who was located in another state. They then immediately called Cooper Roofing, asking us to get on site as quickly as possible. With 24x7 availability, the Cooper team responded immediately.

Within minutes Cooper Roofing Corporation met with the Fire Marshall to explain the roof composition to him. After exchanging information we were both thankful a complete collapse hadn’t occurred. At that time we were all unsure of the extent of damage and if the compromised roof would eventually collapse completely. It appeared that the 10-year-old Firestone membrane was helping to support the enormous weight of the snow and water now ponding in the collapsed area.

With many unanswered questions, and several business owners shut out of their rented space, a true crisis was on our hands. We immediately went into action.

Until the owner could travel to the site we acted as his representative. The Fire Marshall and local authorities wanted to know our opinion of the situation so we needed to conduct an initial inspection, from both above and below the collapsed area. A trip up onto the very dangerous damaged roof was necessary.

Because of the danger involved in not knowing if the roof would completely collapse under our weight we hired a crane to make a safe inspection above the surface of the roof.

The crane, with an articulating boom and personnel bucket, was on site within hours that same day. Until that point there was no evidence of water entering the building. It appeared that the structure had bent under the weight of the snow and water, but did not break, thanks in part to the Firestone roof membrane. Once suspended over the roof in the crane bucket we could clearly see the damaged area, even through the snow and water. From the bucket we dropped a high volume pump into the pool and immediately began pumping out water. In doing this we relieved some of the weight on the compromised roof. Our goal was to stabilize the situation as quickly as possible. Later we would worry about making permanent repairs.

The problem was it was still raining. Since the roof had partially caved in the weakened area had become a sunken ‘pool’ and was attracting even more melting snow and rain. Water weighs approximately 8+ pounds per gallon and the area around the cave-in was getting heavier by the second. The main area was at least 60 feet by 30 feet in overall size with the average depth at about 6 inches. We quickly estimated the volume of water in the sunken area to be approximately 6750 gallons or about 56,000 pounds!

(The formula for this kind of calculation is as follows: [60' x 30' x .5'' (6 inch average depth) = 900. Then multiply 900 x 7.5 (cubic foot of water = 7.5 gallons) to equal total gallons 6750. Next multiply 6750 x 8.34 lbs. (which is the weight of a gallon of water) to equal the total weight 56,295 lbs.])

With the snow load on the roof melting, the pumps had to be turned on during the warmer days (and nights) to keep the weight to a minimum. By now the owner had arrived on site and instructed us to remove as much snow and water as possible from the entire mall roof with snow shovels and additional pumps. Keep in mind the area affected was only a small part of a much larger roof. The remaining snowmelt generated thousands of gallons of water as it thawed on top of the rain that had continued falling through the period. Much of this melt off was finding it’s way to our sunken area. We were monitoring the roof daily, turning pumps on and off in relation to freeze/thaw periods. Cooper Roofing’s goal was to maintain the roofs status quo, avoiding further damage.

Meanwhile, the stores around the cave in had been condemned by the Fire Marshall (for obvious safety reasons). The pressure was on us to somehow permanently stabilize the situation so that the stores could reopen. The building’s owner was about to be responsible for lost revenue every day the stores remained closed. What we had on our hands was more than just a roofing emergency; it was also a financial emergency for the building owner.

We arranged to meet with a structural engineer that day and examine the underside of the compromised roof. We had no choice but to climb stepladders with flashlights in order to evaluate the damaged roof. It wasn’t long before the problem was identified. Faulty welds made at the factory where the structural steel bar joists were fabricated had allowed the excessive snow load to buckle the roof supports. Even the main 18 inch ‘I’ beam on which the bar joists were perched had been twisted under the enormous weight. This too would need replacement. It was ‘a miracle’ that a rupturing of the roof surface hadn’t occurred given all the shock, stress, strain and movement it had endured. That Firestone membrane had held up well!

As the ‘emergency repair’ evolved into a full-blown construction project we assumed the role of General Contractor. The first step in the engineer’s report included immediately adding steel columns to support each of the damaged bar joists across the entire width of the store. Once our steel contractor had them in place the roof was deemed ‘safe’ and the tenants were allowed to reopen businesses. This arrested the ballooning monetary pressure of mandatory store closure.

At that point, having the owner’s complete confidence, we met with the insurance adjuster and negotiated a fair price to permanently restore the roof’s steel substrate and roofing composition to its previous condition. This included removing the damaged steel (bar joists and ‘I’ beam) and then installing new structural steel along with a new roofing system.

This sort of project would require at least 3 days of clear weather with no chance of rain to complete safely. Without that window, and considering the amount of work involved, we would be taking an enormous risk of allowing water damage to the interior. This was something we had been trying to avoid at all costs throughout this ongoing emergency. We didn’t want to fail now, especially since the existing roof was still watertight, so we decided (with the owner’s blessings) to wait for the right weather.

When the 3 good days were targeted we knew we had to make it count. Steel and roofing materials were staged on site ready to be utilized immediately. We pumped the damaged area down for the last time. We were almost through the multiple month emergency.

We arranged with the steel contractor to work long days (and nights) insuring successful completion of this project. Large areas of the roof had to be cut open to allow replacement and/or repair of the damaged structural steel before the new roof deck and system could be installed.


Cooper Roofing completed the steel and roofing work well within the 3-day weather window, without any compromise to the building and it’s contents. In fact, the store remained open for business throughout the 3 day reroofing process! From the start of the project through to final completion no water entered the building!

It wasn’t easy but our final customer challenge had been met. This was truly a world class ‘emergency repair’.

You can count on Cooper Roofing to give your emergency repair needs the same kind of care that we gave this large commercial structure. We have been through enough of them to understand the urgency involved.

The next time a roof emergency hits- remember our name... Cooper Roofing Corporation.

Cooper Roofing Corporation - 610.275.7663 (ROOF)