It’s been roughly 3 weeks since the quotes came back from the contractors who were invited to tender. In the end there were not as many responses as I’d have liked, but still enough to provide a sensible comparison.

My main conclusion is that it’s not going to be possible to build the house I’d ideally like for the budget I have available, so some compromises will be required. I’m sure everyone else who has been in my position has faced the exact same issue!

The outbuildings are the main area where there’s room for compromise. The basic plan for those is to reconstruct the old barn, stable, hay loft and cow sheds that were previously part of the farm complex, for use as storage rooms, garages and workshops. They’re sizeable and cover quite a large area, and hence they’re really quite expensive to build. (I’ve just realized they’re going to cost almost exactly as much to build as I sold my old house for!) I was hoping it would be possible to construct the outbuildings as a water-tight shell for me to fit out later, but to do that would mean making lots of compromises with the specification for the main house which I suspect I’d come to regret. I’ve therefore decided that I’m only going to build the main house at this time and to build (some of) the outbuildings “later”. It took me a few days to come to terms with needing to do that, but now I’m happy it’s the right thing to do.

The contractors on my shortlist are revising their quotes accordingly. Once the amended quotes come back they should (just!) fit within my overall budget, after allowing for contingency etc. which will then leave me with the problem of deciding which contractor to choose.

The detailed drawings for the new house and the outbuildings have been mostly finished since Christmas, as have the detailed specification documents. There were just a couple of technical details needing attention before issuing the tender package – and then there was the question of who should be on the shortlist of contractors that get invited to tender for the build.

The outbuildings are throughly conventional in design and construction and in some ways the main house is too – the basic structure is a block-work cavity wall (albeit one with a very wide cavity) – and many of the less conventional features (like the curved roof) will be outsourced to specialist subcontractors. However, aspects such as the very high degree of air-tightness which is critical to the thermal performance of the main house are fundamental to the success of the building and not yet that common in East Midlands construction. (Passivhaus requires a level of air tightness more than 15 times better than current UK building regulations.)

In some ways it would be best to use a contractor who has previous experience of Passivhaus or near-Passivhaus standards of construction, and in other ways it would be ideal to use someone local who is used to working with local suppliers and sub-contractors. Hopefully there are some contractors who are both local and who have relevant experience, and are available in the right timescales, and offer good value for money…

Justin Smith and his team have worked up a shortlist of contractors who they think would be suitable and the requests for tender went out today. It will be interesting to see what responses come back.