Given how easy it is for rain and snow to puddle and pile up on a flat or low-slope roof, you might wonder why more commercial buildings don't have peaked roofs that allow all the water to run right off. And if you have a commercial building where the flat roof is in bad shape, replacing it with a peaked roof may have crossed your mind briefly if you think that configuration could make the roof leak less and last longer.
Replacing a flat roof with a peaked or sloped roof requires modifying two sides of the building and is not that easy, but the process itself is doable. Yet you don't see many commercial buildings with peaked roofs unless they're converted houses that already had sloped roofs or have flat areas around the sloped areas (such as with skyscrapers that appear to have sloped tops). There are a few reasons for this.
Space for Building Equipment
If your building has air conditioning, it needs to put the main unit somewhere, and for commercial buildings, that's usually on the roof. That equipment needs a relatively flat surface, especially because the people who service that equipment need to be up there to work, and they have to be safe too. If you replace your building's flat roof with a peaked or sloped roof, you'd also need to find a new place for that equipment and then change the wiring or pipe system that connects the equipment to the rest of the building. In other words, this is a reason why you want to replace your old flat roof with another flat roof. You get to keep everything else the same and save money and time.
Similar to the equipment repair reasoning, any roof repairs that need to be done need to allow the workers to remain safe. Working on a sloped roof on a very tall multistory building is not a good idea unless there are areas around the slopes that workers can safely stand on. Take a look at skyscrapers that appear to have pointed or sloped tops and you'll see that the slopes are either ornamental with a wide walkway around them, or they're actually a series of flat levels and walkways piled on top of each other. Again, keeping the flat-roof model when you replace your building's roof is the safest and most cost-effective thing to do.
There are a number of compilation videos that show a lot of multistory buildings with sloped roofs, covered in snow and ice, with the snow suddenly cascading onto the ground far below, damaging cars in the process. If you have a tall commercial building and you convert the flat roof to a sloped roof without adding adequate space around the sloped portions, you could have snow creating the same havoc around your building. It's really much better if you stick to flat roofs and have a snow removal company remove heavy snow from the roofs each winter.
Contact a local roofing company for more info.