embodied energy

Today we laid some concrete down for the first time - apart from the very small pad foundations for the wee shed. This is now functioning well. The two gutters are draining away runoff very well - in the end we finished them with epoxy as a waterproof sealer which also binds the roof membrane. However this is a digression. Despite the fact that we got rained off at about 1700 BST we managed about 30 loads today. This is about 2.4 cubes of C35 mix. So roughly 80 litre mixes. This means we will need to do over a thousand by the time we have got all the concreting done - only 970 to go then. This means about 25 days mixing and laying concrete in the next few months. I mixed and carted and J placed.

We were late onsite too after blethering with Neil and Malcolm at the fish farm then Lindsay and Karen whilst on our way. Blethering is a Gigha pastime. A good blether is a part of island life. This deflective behaviour was because we both had little energy this morning - neither of us sleeping at all well - J woke me up with her amazing snoring - a Bach fugue at 3 a.m.I think it was, but I was going to stay awake for two reasons. One was running through the whole build logistics in my head and the other simply arthritis. So we ended up knackered at normal getting up time and were very slothful in getting moving. Eventually we did arrive down the plot with a two hour window before the rain was due in. In fact we had about 4 hours actually concreting - after we had relevelled the shuttering with the laser level. We eventually got a better than 5mm differential over a 10 metre run so less than 1% out. This is a relearning process for me as it is a long time since I have done much concreting and a new skill for Jayne who actually proved expert at laying, inserting the reinforcing and tamping off. J has a good eye. There was no runoff from the stuff we had done by the time it came on to rain so it must have been level. Thankfully it was light rain and the concrete had mostly gone off so no risk of wash outs.

We are using a lot of concrete in the build as all the floor areas are solid (with 100mm PI foam beneath). This is to create a good sized thermal mass inside the highly insulated structure to store heat. Also it will heat up more slowly and there be less chance of overheating in high summer. Concrete and glass are not the most highly rated eco-materials. We have had to compromise. There is a vast amount of energy used in their production so our house will have a high embodied energy inasmuch as we are laying 90 cubes of concrete in all and have a lot of glass to optimise passive solar gains. Mind you, in energy use the house will have very low energy consumption as the space heating is wood burning, cooking by wood range in winter and hot water from solar and wood range. We are pretty committed to seeking out cost effective LED lighting too.

So despite our own energy levels being pretty much on the low side today we got about a third of the footings done - but in high energy materials and hard graft in mixing and laying.