Disguising simple building shapes

Posted by on Jan 23, 2013 in news | Comments Off on Disguising simple building shapes

Karl Parsons writes…

Having analysed a wide variety of proposed Passivhaus developments/designs, we have become ever more convinced of the need to consider shape early on in the Passivhaus design process. For a given floor area, a complex building form has more heat loss area than a simple building form. Therefore it will require more heating energy. This logic forms the basis of the Passivhaus Heating Energy Demand target of 15kWh/m2yr- or in words 15 kilowatt hours of heating energy for every square metre of floor area, per year.

BBoth architects and clients can be concerned that, taken to its logical conclusion, adherence to the Passivhaus methodology will result in uniform rows of terraced boxes, with no individuality or aesthetic value. This needn’t, and indeed shouldn’t, be the case. While the building form, or more precisely the thermal envelope, should be simple in order to minimise the heating energy demand, the appearance need not slavishly follow the thermal envelope. Furthermore, surface treatments can be used to provide visual interest. Ford Close, the first Passivhaus certified scheme in Cornwall, was designed by Mitchell Architects and aimed to disguise a relatively simple envelope with varying roof treatments, externally mounted balconies and porches, along with colour and material variations.

Disguising a simple form isn’t of course a 21st century idea. One of the most impressive Plymouth city centre buildings, the National Provincial Bank which forms one end of the grand axis of Royal Parade, has a very simple shape which is masked by material and colour changes. Stone contrasts with Venetian glass mosaic tiles, with a portico projecting from the front of the building adding depth and further masking the overall simplicity. A quick look at buildings from any part of our rich architectural heritage will produce plenty of examples where simple forms have been masked by detailing, by material changes and by external features such as porches and overhanging eaves. These external features often serve a dual purpose, such as transporting water away from the building, but do so in a way which is aesthetically pleasing.

NPB2 (600 x 450)

 

As a Passivhaus Designer, my challenge to current architects is to design simple thermal envelopes, but get creative with appearance. Thermal efficiency shouldn’t be boring!