High Performing Buildings - Fall 2011 - (Page 67)
L e t t e R s
Insulating Historic Structures
The Summer 2011 issue of High Performing Buildings has articles on two handsome renovation projects: The Christman Building in Lansing, Mich., and the Cannon Design Office in St. Louis. The projects were clearly designed with considerable care, and the results are very attractive new commercial facilities.
he concern I would express is over the lack of wall thermal insulation. These buildings are in heating dominated climates. With solid masonry walls that have an R-value around 3 (Christman, R-3.53), a large portion of heating/ cooling energy will be devoted to meeting wall thermal loss for many, many years. The uninsulated walls may also be a comfort issue, though Cannon cleverly pulls the work spaces away from the walls on cantilever floors. It is fascinating to see how the actual energy use tracks the actual heating degree days for the Cannon office, a clear indication of exterior load domination. Both buildings have historic significance, and the renovation has been done with great sensitivity. It is deeply discouraging to read the statement on the Christman Building, “The preservation standards did not allow insulation to be added to the walls.” So the thermal crippling of the building is not due to any action of the owner or architect but is a function of the preservation standards. The Cannon Design interior wall surfaces are left exposed, likely for aesthetic as well as preservation reasons. Buildings renovated within historic preservation guidelines
contain much that is non-historic: HVAC systems, plumbing and electrical systems, partitioning, etc. In the case of the Christman Building, the inside walls have been re-finished with plaster. The incorporation of these contemporary systems revitalizes the structures to meet the needs of today’s society. To not include thermal improvements means that these buildings do not truly meet contemporary performance needs, even though we now have technologies to effectively insulate masonry structures, most notably closed cell spray-foam systems easily concealed behind wall finishes. What these circumstances suggest is, perhaps, the development of a new class of “Historic Renovated Structures” that preserve the exterior of a building but allow good thermal upgrading in walls, roof, and windows along with the full range of systems renewal. In many cases this can also be compatible with the restoration of historic interior spaces. Historic buildings are a valuable component of our built environment. When renovated for contemporary use they must meet the needs for thermal efficiency as well as all others.
John K. Holton, FAiA/P .e.
Top The Christman Building in Lansing, Mich. Above Cannon Design Office in St. Louis.
Response From Author
As with most projects, there is a fixed budget. The Christman Building project was also a development project further reducing the funding available. We agree that optimally the exterior wall should have been insulated but in this case it was just not an affordable option. Comfort conditions are maintained with perimeter radiation and an UFAD system. Energy efficiency is achieved by the wide variety of technologies installed, as described in the article, and by careful, continuous attention to fine-tuning building operation to occupancy and climatic conditions.
gavin gardi, sustainable Programs manager, The Christman Company To comment on all HPB articles, visit http://hpbmagazine.org. To comment on The Christman Building and the Cannon Design Office articles, go to http://tinyurl.com/christmanbldg or http://tinyurl.com/pwrhouse.
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Table of Contents for the Digital Edition of High Performing Buildings - Fall 2011
High Performing Buildings - Fall 2011
Manitoba Hydro Place
Maplewood Police and Court Building
Omega Center for Sustainable Living
Dockside Synergy at Dockside Green
Golden Hill Office Center
Letters to the Editor
High Performing Buildings - Fall 2011