Masonry Magazine February 2001 Page. 14
Masonry: The Ancient and Contemporary
Masonry veneer is often chosen as the primary enclosure system for buildings, even those with quickly erected steel frames. This choice is likely due to a combination of objective reasoning and stylistic inertia, as masonry has been successfully used in the past.
Masonry construction is both ancient and contemporary. Kiln-fired bricks have been used for over five millennia, and concrete masonry units were first used in Roman architecture two millennia ago. Our collective wisdom and experience with masonry construction is now at an all-time high. We know how to make masonry buildings that can provide unmatched qualities of strength, enclosure, durability, and beauty. Masonry materials are environmentally sound, low maintenance, and are easily combined to create great varieties of architectural form.
The Masonry Society and its members have gathered and disseminated unprecedented amounts of valuable information about how a masonry system can work, if properly executed. We know how to make excellent reinforced walls, cavity walls, and veneer walls. We can even make sophisticated masonry rain-screen walls that repel moisture by using pressure equalization between the cavity and the outside wind pressure. Today we benefit from centuries of practical experience combined with insights gained from recent rigorous scientific research. Knowledge about how to design a masonry building has never been better than it is now.
The challenge for designers and builders in today's construction industry is to ensure that future architects, owners, and builders continue to choose masonry construction. Although masonry construction has evolved significantly in the past 50 years, changes in the larger context of the construction industry have changed even more dramatically. The question is, how will the masonry industry adapt to keep pace with new circumstances?
The central challenge regarding masonry construction today is how to match today's superior knowledge as designers with superior means of implementation. Advances in theoretical design have not been matched by advances in practical implementation. In fact, many architects feel that masonry and other construction trades have actually declined significantly in the past several decades.
There are two possible explanations for this perception. One is that the contemporary mason may be less knowledgeable and less well trained and thus, less skilled than his predecessor. This position is illustrated with the following message from architect Jim Robertson of Daughtrey Robertson, Charlotte, NC: "The masons on the jobs today vary greatly in their level of skill and their knowledge about the principles behind the design of the wall. Architects need to know whether the tradesman is an A, a C or an F tradesman. Most are a C. The Architect needs to be able to look at the work and decide whether it is a C job versus a D or F job."
The other possible explanation is that the masonry wall is too complex for the mason to properly execute in the fast-paced contemporary project. In other words, our designs have reached a level of sophistication that is not practically attainable in the field.
Building badly is unacceptable. Clients increasingly expect consistency and competency in the finished product. They expect a certain level of performance, and that level of performance is often very high. They do not tolerate exterior walls that may not repel the weather, resist gravity nor age well. Nor should they.
More than any other construction system, the quality and long-term performance of the finished masonry building is more dependent upon skilled, conscientious on-site work. As noted above, architects are uncertain about the quality of workmanship they will get in the field today. They are therefore uncertain whether the masonry wall will perform as intended. It is difficult to reduce anxiety that workmanship is not high because, especially in masonry construction, the work cannot easily be observed nor inspected except at the moment it is being built. Nobody, not even the mason, knows with certainty whether the cavity and weeps are clear of mortar droppings once the wall is up a few feet.
"Don't expect what you don't inspect." This advice to was given to architects in 1995 from Doug Burton, at that time President of the North Carolina Mason Association. Architects cannot possibly observe all masonry work at all times. Even a full time on-site representative cannot be expected to do this. Masonry work is uninspectable with any specificity. This is a disadvantage in today's competitive market in which quality assurance is one of the owner's selection criteria. Innovation is needed to help the mason and the architect set clear common expectations which can be matched by measurable observations. Skilled masons