Commercial roofing services often ask the building owners if they want a ledge all the way around the top of the flat roof. There are pros and cons to having a ledge, to be sure, but the question has to be asked and discussed during the construction process all the same. If you are having a new commercial building or new addition to your existing building constructed, here is how to decide if you want to add the ledge or go ledge-less.
Argument for the Ledge
The biggest argument for the ledge is to protect the rest of the building, of course. The ledge prevents water from constantly running down the sides of the building from the room. The ledge keeps the water heading away from the edges of the roof and toward a drain hole, and then down and out of the downspout.
A ledge is also a safety matter. It is more difficult to fall from the top of a building when there is a ledge onto which to grab. A really thick, sturdy ledge also lends itself well to installing an eight-foot chain-link fence around the top of the roof so that nobody can attempt to jump onto or off of the roof.
Argument Against the Ledge
Ledges do face a lot of weathering. They have to be checked a couple times a year to make sure that they are not cracked and crumbling onto people's heads below. If a ledge is cracked and/or starts to crumble, commercial roofing services have to come to the building and repair the cracked and crumbling portions of the ledges to prevent injuries to people down on the sidewalk and street.
Additionally, the ledge-less buildings have less maintenance to do. Because they are extremely flat, they can be leveled and have concrete and/or asphalt applied to the top of the roof to seal it. Eavestroughs are installed by bolting them to the sides of the building all the way around the edges of the roof. Water flows directly into the troughs and then is funneled to a downspout. No drain holes are needed in this type of commercial roof, which is why it is easier and cheaper to construct. You will, however, have to climb up there (or have a roofing service climb up there) in winter to remove snow and ice to prevent roofing cave-ins and damage at a much later date. You will also have to resurface a flat, ledge-less commercial roof more often than a roof with ledges.