Damage to Roofing Systems By Other Trades, The Consequences And The Cure

July 1969

The Canadian roofing industry has, for the past century, been plagued with problems of varying degrees of complexity. It is probably safe to say that a major portion of these problems have been controlled or eliminated. The intent of this article is to deal with what is probably still the most frustrating of all failures, damage to the roofing system by other trades.

This type of failure is relatively new in comparison with the age of the industry but seems to be increasing in severity. The basic cause of this problem of course is the modern design of multi level buildings combined with increasing amounts of equipment being placed over the deck surface.

The roofing contractor in the past was usually one of the last trades to work above the deck surface. To day however the roofer completes his roofing system only to be followed by a veritable army of the other trades dragging their equipment and behind them.  These trades range from mechanical and electrical to brick layers and steel erectors just to mention a few.

Obviously much more is expected from the modem day roof than the original design intended; that of waterproofing the deck surface. In this day and age the completed roof is expected to serve as a highway, workshop, storage area for building materials, base for scaffolding and finally a convenient area for dumping left over or unusable materials such as form boards and broken concrete blocks. It seems a certainty that the average tradesman views the gravelled surface of a roof in the same light as a gravelled surface on the ground, considering it to be impervious to damage.

The consequences of a few careless tradesmen can be very   far reaching, extending from immediate failure to those occurring several years after building completion. The costs can vary from those of minor repairs to complete roof replacement. In some instances, the complete roof replacement may only amount to a fraction of the total interior repair costs. The costs of damages detected during the period governed by general contract conditions are usually borne by the designer, general contractor or roofing contractor in lost time costs examining the roof and actual repair costs which can seldom be recovered. More often than not a roofer will be forced to pay for this type of repair in order to receive his final contract payment. In most instances the party or parties paying the repair costs are not responsible for the damage that necessitated repair.

Those damages, sometimes undetected for several years, cost the owners thousands of dollars by way of litigation or complete roof replacement costs. Quite a price to pay for a few hours or minutes of carelessness on the part of tradesmen who do not respect the work of others or who are actually unaware of the consequences of their actions.

The solution to the problem is not a difficult one. Quite simply it boils down to education of the trades usually involved with these damages which in turn will lead to prevention.

Obviously in the case of roofing a clause in the specifications stating that the trade causing damages to the roof will be responsible for the cost of repair is inadequate. Neither is a specification attempting to make the roofer responsible for protecting his work from damage by other trades. This specification would require a roofing contractor to ensure a man was on the job site from the commencement of roofing until the completion of the entire project.

The design authorities could minimize this problem in several ways. If the designer is in doubt as to what constitutes adequate protection of the membrane, a call to the roofing association or roofer in his area would bring a quick response. Having established the point, he should specifically state in the specifications what each trade involved must do to protect their specific work area. Further the designer can specify that the general contractor, as the only general supervisor on the project from beginning to end, is required to ensure that roof protection, as specified, is properly carried out.

This of course will raise costs slightly, but only a fraction of the amount required to replace large roof areas damaged beyond repair.

Undoubtedly, if the designer, general contractor and roofing contractor decide to wholly cooperate in this matter totally unnecessary loss of time and money be prevented.