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What should I look for in a Green Builder?

How do you find a green builder to help you make your eco house refurbishment a dream come true?  What qualities should you look for in a builder, when should you get them involved and how can you work with them to best effect?

Architect John Christophers explains how he found the right green builder to help him take a Victorian terrace and convert it into a zero carbon SuperHome.

Is there such a thing as a ‘green’ builder?

Zero carbon house is half 1840 Victorian terraced house and half 2009 extension. Both the new and the old construction meet zero carbon standards. (c) Martine Hamilton Knight.

Zero carbon house is half 1840 Victorian terraced house and half 2009 extension. Both the new and the old construction meet zero carbon standards. (c) Martine Hamilton Knight.

If you are seeking a green builder, membership of AECB, an environmental conscious or experience of retrofit is certainly a good start, but builders are not all alike.

Other qualities are perhaps equally important including trust, sharing your vision, problem solving ability, good scheduling and reliability.

Choose the right builder

When converting and extending our zero carbon in Birmingham 2008/9, we started with criteria about the kind of builder we wanted:

  1. An organised site agent with wisdom and excellent communication skills
  2. Experience of this scale of work
  3. Good references/recommendations

A flexible can-do attitude and genuine interest in what we wanted were important, but we realised no one would have experience of all the building materials we were using (eg. rammed earth floors) or airtight targets (we achieved Q50=0.97, 10x better than Building Regulations).

This raised the problem that if we went out to competitive tender, we would probably receive very high quotes because people would be wary of the unknown.¹ So some form of selection based on quality rather than price, followed by cost negotiation was necessary.  And that in turn meant we needed a team we could trust completely.

Involve your builder

Top floor studio under solar roof.  The white doors are standard widths; cost savings allowed us to have them all factory-lacquered within our budget. (c) Martine Hamilton Knight.

Top floor studio under solar roof. The white doors are standard widths; cost savings allowed us to have them all factory-lacquered within our budget. (c) Martine Hamilton Knight.

We considered larger and smaller builders, and talked to them about the scheme.  We had greatest confidence in Bill Cave and his team from Speller Metcalfe, but before committing to a contract we agreed to negotiate costs.

There can be advantages in involving a builder in the design process.  We had planning permission but only draft working drawings.  Over four or five fortnightly meetings with Bill we were able to start budgeting and problem solving.

These meetings shaped parts of the construction (eg. the type of construction, restricted because of limited site space) and we were able to focus on getting prices for the main sub-contractor packages.

The builder’s advice was invaluable, identifying good value from smaller suppliers on low risk items (eg. doors) and where we needed more experienced sub-contractors (eg. heat recovery ventilation).

Share the risks, share the savings

Rather than a fixed price, we agreed an “open book” contract.  The builder showed us every quote, timesheet and invoice and we paid the actual cost of the work.  We agreed a target cost plan for each element of work – carpentry, electrical wiring, light fittings, etc.² Costs were reviewed every month so we could keep track of progress.  With only one exception, we kept every element within or below budget.

Manage the risks

Our windows are one example of when this team approach really made a difference to the delivery.  It became clear the sub-contractor who had priced the frameless triple-glazed units was out of his depth and might let us down.  We agreed with the builder that another sub-contractor should do this work.  The slightly more expensive quote was greatly outweighed by time/cost savings on site, avoiding a big risk to progress, quality and cost.

As we were jointly sharing the cost risk with the builder, we were jointly motivated to reduce or eliminate all those risks.  Neither of us wanted to sit back and think it was someone else’s problem.

Be hands on

Nurturing green builders - Niall Crosson from Ecological Building Systems trained the site team installing airtight membranes, so the critical areas of work were completely understood.

Niall Crosson from Ecological Building Systems trained the site team installing airtight membranes, so the critical areas of work were completely understood.

I think the success of our approach was partly because we had such a good site agent in Dell Browne.  As client/architect, I was able to visit the site 3-4 times each week so we could agree in advance exactly how each area of work would be carried out, and therefore do it right, efficiently, first time, with benefits for everyone.

Site inspection is not just about looking at the standard and quality of work being done – important though it is to agree that as work proceeds.  It’s about thinking ahead so nothing will need to be changed by following trades.

As a lot of site work goes on at once it’s essential to have detail drawings and discussions (confirmed with written notes) to communicate the design intention clearly, highlight any unusual aspects, make it as easy as possible to build well, and to keep a check on the quality of the work etc.

© John Christophers, Mar 2013. John works for Associated Architects in Birmingham.

Notes:

1. With standard building contracts (JCT), most of the risk of things going wrong – eg. availability of materials, weather, labour, sub-contractors, etc – is taken by the builder.  If the site is awkward or the type of construction is unfamiliar, he will price extra for that risk, and the client will then pay that price, whether there are problems or not.

2. The form of contract we used was NEC3, option E.  Other contract options within NEC can allow a guaranteed maximum price (ie. the cost to the client may be lower but not higher than X), and any savings from agreed targets can be shared in agreed proportions between the client and builder.

Further Information:
You can find out more about John Christophers’ SuperHome at Open Days in September. This family home has won 6 design awards. Further details are available on the Zero Carbon House website.

Also see:
My Green Builder database
The Green Register
Taking a green retrofit to Passivhaus standard
Green boilers
Green Deal review

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