Piers Taylor from Invisible Studio Architects explains what a build system is, why you would use one over another and whether any are preferable when it comes to creating low energy houses.
Interview with Piers Taylor
It was after seeing an inspirational talk by Glenn Murcutt in Sydney that Piers Taylor decided he wanted to become an architect.
A Building System is the Method Chosen to Construct the Building
Piers talks of these in terms of lightweight and heavyweight, and on-site and off-site construction, as most one-off individual homes will fit into these categories.
It is Easier to Achieve a High Quality Finish With a “Lightweight” Timber Building
When answering the questions of what is most efficient, most economically sound and best environmentally, timber is the material which Piers instinctively selects.
Timber is a renewable and readily available material, comparatively cheap, very workable on-site and can be used by people with varying degrees of skill and experience.
With Passivhaus requiring airtightness and quality of workmanship, Piers believes that a stud framed building is ideally suited.
It is Generally More Efficient to Build On-site Rather Than Pre-fabricated
Piers had laboured under the misapprehension that to build in a factory was the better way to do things, however when the expenses of factory rent, labour and heating are taken into account, when it comes to single buildings he believes that making things by hand on-site is more efficient.
There are Far Fewer Passivhauses Made of Masonry Than of Timber
While masonry buildings do have the advantage of thermal mass, Piers explains that it is harder to achieve a good quality finish with blockwork and wet trades. He puts this partly down to tradesmen putting them together crudely, with the assumption that someone else will be doing the finishes.
There is a Place for Concrete as an Environmentally Sound Material in Big Span Construction
Concrete has a smaller carbon footprint than if it were replaced in big span construction by steel for example. The problem is often the amount used, rather than the material itself, with laziness often causing its overuse. Piers doesn’t see a place for it in domestic houses, unless there is a particular desire for a thermal mass in the floor.
SIPs (Structural Insulated Panels) Don’t Have Any Real Advantages in Individual Houses
The advantages of SIPs panels lie in larger projects where economies of scale are a factor. For a domestic property they are expensive as the factory overheads are included in the cost, they contain all sorts of formaldehydes and glues, and they can’t just be made on-site.
While SIPs panels appear to be constructed quickly, it could be argued that making a timber frame in a factory would be just as quick.
Piers summarises that the ideal use for SIPs panels are for buildings with big roof spans, multiple buildings where an application is being repeated and where the walls are required to have a structural capability without the need for beams.
Big Volume House-Builders are Efficient in Terms of Their Construction
Piers accepts that, whilst we may not like what they build, big volume house builders have honed their methods of construction to be hugely efficient, as they’re making all the component parts on-site, and are therefore not paying factory overheads.
The Passivhaus Standard is Achievable With Any Construction Method But is Largely Dependent on the Quality of Craftsmanship
As Passivhaus is about achieving a good standard of fit to create building performance, rather than being interested in thermal mass, it is something that is not as easy to achieve with masonry.
Straw Bales May Not be That Efficient But Their Advantage Lies in Being so Locally Produced
Straw bales are relatively inefficient because they are bulky and not great insulators compared with some other materials. However, they are loved by some as a construction method as they are low tech, available, cheap and usually haven’t had to travel far – something that is sometimes overlooked with timber which, unless it’s come from a local sawmill, can often be shipped from Scotland, Scandinavia or Canada.
A Build System is Invariably Better When it Influences the Look of the House
Piers’ preference is to have the constructional system visible and legible to show what the different parts are actually doing, rather than the sanitised approach to current construction where everything is hidden behind plasterboard.
Piers sees a beautiful precision in timber, unlike the less aesthetically pleasing concrete block and steel which invariably have to be covered up because the fit is not good.
As with SIPs panels, there is often no call for steel frames in a domestic building as the spans don’t necessitate it and it is an expensive option.
Projects are Immeasurably Better if How They’re Made Forms an Early Part of the Building Decision
An early decision should be made on what is going to be the most appropriate material to use as this will give the building its character. By exploring all sorts of options you can gradually hone in with greater certainty on one thing.
Part of this early conversation should be focussing on efficiency, in terms of using materials intelligently and sensibly, without being wasteful, and these are things that need to be balanced with what the building is going to look and feel like.
Timber is the Best Material to Use For Keeping it Simple
Many self-builders will be doing a project for the first time so Piers’ advice is to keep it simple. Timber is quick, efficient, available everywhere, anyone can use it and it doesn’t harm the environment if it is chosen wisely, and with its only real drawback being lack of thermal mass, Piers considers it to be the best system to use.
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UK Passivhaus Awards 2014
The shortlist for this year's UK Passivhaus Awards has been been unveiled. Good luck to all those involved!
Check out some of last year's projects.
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