Sustainability Also has a Price

  • Building Design Expert
  • 6 years ago

You may have heard the expression that “the law is an ass”!? It’s there with every good intention to keep us all safe and free from harm. But, every now and again there’s an anomaly that is just not typical of every day life, and it fails miserably to protect the victim.

The Building Regulations of course fall under the Building Act – a legal entity. Within the Building Regulations is a very prescriptive framework – the Standard Assessment Procedure (SAP), the method of measurement used in assessing a new building’s overall ability to meet what is intended to be an holistic approach to ‘Sustainability’.

The ideology used is essentially laudable, and does it’s best to cover a number of key bases including energy use / CO2 emissions, water recycling, type of building materials, and even extends to cover occupant health and site ecology. OK, great, where’s the problem?

It’s a credit, or points based system that controls, amongst other things, the outcome of designs for the Code for Sustainable Homes (CSH). The ratings are directly attributable to achieving ‘code 3’ or ‘code 6’, or any where in-between.

The higher the code rating the more points we need. So consider for a moment the home owner buys a washing machine. Of course the appliance will be A+, or A++ rated. It uses the least soap powder, the least water, the least energy, but does that make it sustainable? What about the embodied energy it carries through manufacture, transport, storage, packaging? At some point it’s also going to wear out and fail. The owner will replace it with the next A++++ unit which will use less – etc. etc…. While the old unit goes to landfill!!! – Sustainable?

Of course the truly sustainable solution would be to use the recycled water from the rain water harvesting tank, eco-friendly soap and a wash board, or better still visit the nearest river and beat the dirty clothes with stones. Whilst this may be taking things a bit far, the point is that our A++ appliance will help tick the boxes required to achieve a high CSH code rating. But is this ‘sustainability’ with our eyes wide shut?

That may have been a loose example. So let’s look at a key part of the building envelope: The pvcU window frame has proved very popular both with architectural specifiers and home owners alike. Why not? After all it’s inexpensive,  thermally efficient, reasonably maintenance free, and looks acceptable. Under SAP it achieves an A+ rating, so that’s that one sorted. Except, it’s main constituent material is based in fossil fuel. It has been manufactured in a huge factory in Germany, using huge amounts of energy. It has been transported to the UK for assembly, using more fossil fuel and more more factory processes. Stored, and transported to site. They have a design life of 25 years. Don’t forget that gets an A+!!!

Just down the road from the development site there’s a small specialist joinery wokshop. They have access to a sustainable source of locally grown oak. So local that it’s on the same site as the work shop. They make oak window frames. They look beautiful. They will take double or triple glazed units. In fact you have only to tell them what you want, because everything is made to order. Any design. Any quantity. With a little maintenance they will out last us all. Under SAP such a product would be awarded a ‘B’.

Don’t forget this is the ‘Code for Sustainable Homes’. Which window frame is more ‘sustainable’?

Let us take this point to a further conclusion:

House 1 (below) – has been constructed with a fibre cement tiled roof. The walls are brick / block cavity construction. The insulation is rigid foam board. Oh, and the windows are pvcU. Achieving CSH 5

House 1 - will achieve Code for Sustainable Homes rating 5

House 2 (below)- has been constructed with a thatched roof. Walls of lime rendered straw bales. Lambs wool insulation, and oak framed windows. Achieving CSH 3/4

House 2 - will achieve Code for Sustainable Homes rating 3/4

So, yes. The law is sometimes an ass, and sustainability also has a price.

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Photographs courtesy of a presentation by Foamglas