Practical Considerations for Economical, Sustainable, and Compatible Conservation of Historic Buildings

As we strive to make better use of our built heritage in a more sustainable and energy efficient future, it becomes critical to understand the materials, construction methodologies, and building standards of the past. The longstanding solution to construction was to demolish the old and construct anew, using the most current materials and methodologies. This resulted in lost knowledge of traditional practices and construction techniques. With the onset of sustainable design, and the drive to protect our environment and its resources, the construction industry and building owners began to look at ways to adapt and reuse our existing built heritage. Over 50% of construction projects today involve adaptive reuse. Determining how to blend contemporary codes, standards, materials, and construction methodologies, with those of our historic infrastructure poses a challenge. Schooling in general does not teach design, construction methodologies, and comprehension of historic materials. It is only recently that Carleton University and Algonquin College in Ottawa offer courses in Conservation Design and Construction to address this issue. Failure to fully conserve masonry, and understand how it performs, prior to reinforcing the masonry for current loading requirements, use of incompatible construction materials and structural solutions such as use of overly strong mortars, reinforcement of masonry using steel frames or concrete, reinforcing original timber structures without considering the entire strength of this timber, result in excessive costs, increased risk of material deterioration and structural damage over time. Striving for Net Zero, without an in-depth understanding of the historic material composition and construction systems, will lead to decay and damage to existing building envelopes in very short order. The solution is simple. A better understanding of historic structures, materials used, construction techniques, and Codes and Standards under which they were built provides the design consultants and contractors with a more compatible and efficient way to achieve our goal of Net Zero, without destroying our existing built heritage.