b'INDUSTRY ROUNDTABLEAs for looking to the past, building layouts are usually logical andThere are two key things we can take from the historical past functional, both economically and practically. They are also, in manyand will continue to use well into the future: the historical cases, conducive to different uses and layout reprogramming withoutdesign of the windows and the method of through mortise and much structural strain. The size of window openings are directlytenon joinery. As we continue to meet these new performance linked to achieving livability and good energy efficiency through thestandards, we find that each change takes away from the existing balanced solid-to-void ratio on facades. The thickness of brick wallscomponents that once lasted many generations. For example, facing north would often be more substantive than elsewhere on theas the original brass weatherstripping is changed out to vinyl building, especially if the wall is exposed to elements; natural ventila- weatherstripping for the purpose of testing under pressure or tion principles applied in some buildings sustained their lifespanvacuum, it would now have to be replaced every 20 years versus without reliance on heavily engineered mechanical equipment. Inever. And as the glass is changed from single glazed to thermal am not saying this works everywhere, but there are some good anddouble glazing, it now has to be changed every 20 years versus simple solutions that we should rediscover and use them when itnever. Then, as the glue and sealants are now being used, they make sense.tend to break down with time. These stringent building perfor-DL: We need to understand each building holistically if we are evermance requirements sacrifice longevity and add to the cost of the going to achieve successful heritage conservation. For years I havelifetime of the product. advocated for the idea of Rehabilitation Sub-Codes, such as the onesZJ: There is a way to still accommodate retention of heritage that were pioneered by the State of New Jersey, for existing andvalues and features of the heritage building while achieving historic buildings. This would allow more flexibility, as well as saveenergy efficiency improvements. The Chief Building Offi-substantial costs in the rehabilitation process by recognizing thecial (CBO) has the authority to exercise his/her discretion in inherent performance of each structure. providing relaxations for heritage buildings wherever some I always refer people to Building Resilience: Practical Guidelines forrelated improvements can still be achieved. In other words, not the Sustainable Rehabilitation of Existing Buildings in Canada as aall requirements may need to be delivered when dealing with starting point. It is the companion document to the Standards andheritage buildingsor not to its full extent, as long as the CBO Guidelines for the Conservation of Historic Places in Canada. Itshas enough information on alternate solutions proposed and a brilliant piece of work that everyone should know about, as it recog- a proper heritage rationale for not being able to fully meet the nizes different techniques to achieve both heritage conservation andVBBL or other requirements. The current VBBL has brought sustainability objectives. forward additional clarification, and there is a related bulletin available to provide further clarity and guidelines to professionals BE: With more stringent building energy performance require- involved with heritage projects. ments becoming increasingly important, how does this affectDL: We need to use all of the tools in our toolbox. The process heritage conservation work? outlined in Building Resilience is the starting pointthat you KB: With the ever-increasing building performance requirements, wemust understand the building in a holistic and significant way find our conservation work has to be even more on-point to meetwithout going straight to standard solutions. It requires sensitive and exceed these requirements. We continue to do research andand creative thinking, and we have seen it work. We can achieve testing and find advanced methods and products to allow our tradeboth sensitive conservation AND improved energy performance; to continue. we dont have to choose one or the other. STEVE TYNE, CTR IRC BUILDING SCIENCES GROUPClient Development Manager,Roof ConsultingBritish Columbia Bringing the c: 604.842.0579Building Envelopef: 204.633.8218Science of s.tyne@alumicor.com BuildingsStructural EngineeringALUMICOR LIMITED VANCOUVER, BC into Focus. Pavement EngineeringIRC Building Sciences Group vancouver@ircgroup.com WWW.ALUMICOR.COM CONSULTING | ENGINEERING | DESIGN 604.295.8070 20 BCBEC ELEMENTSA BCBEC PUBLICATION'