Coping stones are a common feature on multiple dwellings and commercial buildings. This simple construction feature can be hazardous to firefighters on the ground and those ascending to the roof if not understood. These stones are held in place by mortar which can loosen up over time. Water under the stones can freeze and expand which will also loosen the stones over the years.
When throwing portable ladders against the wall a small piece may break off and fall to the ground but rarely will the entire coping stone fall. The real concern is when a firefighter ascends either a portable or aerial ladder to the roof and then goes to step off of the ladder. These stones have a smooth surface which becomes very slippery when wet or covered with snow. Also, these stones can have very fine cracks that are hard to see. Once the weight of a firefighter is places on top of the stone it may crumble under the firefighters foot. If the parapet wall is not very high it is best to try to step directly onto the roof surface to avoid slipping on the slick or broken coping stones. If that is not possible be sure to hold onto the ladder tightly and check your footing before shifting your weight. As always, when dismounting a ladder, drop your tools and equipment to the roof surface first.
When conducting your perimeter survey be mindful of loose coping stones as well. Leaning over the roofs edge is necessary, just be sure not to knock loose stones off!
A loose coping stone can also be our friend in some cases. After forcing the bulkhead door (doorway leading to the roof from the interior stairwell), I will either grab a loose one (again, very common) or knock one loose with a quick shot from the Halligan, and use it to chock the bulkhead door.
This is a better option, in my opinion than dropping a tool (hook and/or roof rope) to chock the door open, and they are readily available on most roofs.
Stay safe!