Explanatory Notes on the CRCA Specification Manual
12 – July 1971
A roof exists for one reason – to keep the elements out of the building. Because of the nature of the materials used in the roofing process, the actual roof must be manufactured on the job site from these basic materials, which range from asphalts and felts – to shingles – to spray and coating systems. They all have one thing in common. It is the skill and thoroughness of the tradesmen on the job which converts these basic materials into waterproof systems.
A procedure and approach that makes for a good roof one day, may have to be varied the next due to climatic conditions. Winter techniques must vary from summer techniques. The intent, of course, is to obtain a roof that will be serviceable and workable notwithstanding the conditions under which is has to be applied.
With this in mind, we must accept the fact that a roofing specification, at best, is only a guideline to the production of a serviceable roof. It must not and cannot be construed as a certain formula for good roofing. This industry has noted that, in too many cases, those responsible for roof inspection tend to direct their energies to seeing that book procedures are followed to a “T” while neglecting to ascertain whether the end product is or is not a durable and long lasting waterproofing element. We in the roofing industry, know, for example, that adhesion between felts is more important to a roof than merely the amount of bitumen used.
In order to get the best roof under a great variety of conditions, we must reaffirm the intent of the CRCA Specification Manual to provide a sensible guideline for specifying authorities to follow in setting out their roofing, insulation, flashing and waterproofing requirements. When the specification reads “approximately 20 lbs. of asphalt”, it means that this is the amount of asphalt that will be necessary for an adequate job under average conditions. If the weather is very hot, a little less will be used, if the weather is cold – a little more.
The designer would be well advised thoroughly to acquaint himself with the “General Conditions” section of the CRCA manual. Much common sense and valuable information is contained in this section, which, if followed, will add measurable quality to all roof applications.