In my experience the roof is one thing most buyers and tenants with triple net leases have the most attention on and rightfully so. Proper maintenance and routine inspections are strongly advised.
The typical commercial and industrial roof is a “flat” roof. This means that is has less than 2” of slope or fall for every level foot. Modern standards require all roofing to have a minimum of ¼” of slope for every level foot. This was rarely the case in roofing before the 70’s. Most any roof built in the 70’s and before is almost always very flat and does not shed water well. This leaves areas of standing water. Standing water is a potential problem for two reasons; #1 is when water stands it has a way of finding a weak spot and leaking. #2 is standing water collects dirt and debris that will cause the roofing material to deteriorate faster and leak quicker. (Standing water is any water that is either ½” deep or more and not flowing or is there more than 48 hours after the rain has stopped.)
From my experience maintenance is the single area that can prolong almost all aspects of any building. Proper maintenance of the roof is the cheapest insurance there is. If every owner had a roofer go over the roof every 2-3 years (once it is at least 5 years old) and make any repairs as well as do all the normal preventative maintenance, a roof can last well past its expected useful life.
The usual expected useful life of a flat roof is approximately 13 – 17 years with many roofing materials, if properly maintained, lasting 20 years.
