Week two has been quite eventful. The old windows are out and much progress made in digging trenches for the external insulation and preparing the foundation for the new build element to the side of the house.
All (I hope) of the shortcomings of the existing building have now been exposed and this week I have found myself questioning why we are bothering to refurb and not demolishing what is left and starting again. If we had chosen to demolish it, we would have been able to do away with many hours of difficult design work. The problems of thermal bridging between the ground floor concrete slab and the structural walls would have gone away in an instant. We wouldn't be paying tens of thousands in VAT, as VAT can be claimed back for new builds.
Our builder mentioned as an aside that we could have brought in a big machine that, in no time at all, would have crunched up the concrete that makes up so much of the mass of the existing building. We could have sold it for hardcore at £3 or £4 a bag. This is a good point against the pro-refurbishment argument about saving embodied energy, as the energy in the crunched up concrete would still have had a use in the future, if we'd gone down the new build route.
Despite that, I still strongly believe there is tremendous value in what we are doing. Even if the economics in our case is likely to be marginal, there will be many lessons to be learned from this project for us personally and, I hope, for others for whom refurbishment is the only option.
We still haven't placed our window order and I am now getting quite nervous about it. Having spent so much time and effort optimising our spend and the work programme, I can see money being wasted because of the delays in finalising the windows.
During the week a gas leak was discovered and the site was temporarily evacuated until the leak was provisionally patched up. The local gas infrastructure company is coming back early next week to replace all the pipework from the street to the house. The old pipe was completely rusted away and, as soon as it was exposed, began to leak a lot of gas. It amazes me that a house that was built on a green field site 40 years ago could have been connected to the gas grid with pipework that had no chance of lasting. I have to assume that the gas has been slowly seeping through the ground for many years and that our situation is far from uncommon. If that's true, not only have we been building homes that waste energy hugely, the gas grid itself is wasting gas before it even reaches our gas meters.