Progress. The balcony, patio area and log store outside the main building are now substantially finished.
It has been quite a transformation.
The schist patio creates a large outside eating area and connects the log store and battery house to the main building.
Yes, Portland cement-based mortar has been used. It’s a material I feel as ambivalent about as a lot of the green and eco-building movement seems to. Is it ‘natural’ and ‘eco-friendly’ or isn’t it? The stuff’s credentials are as grey an area as its colour.
In composition, it’s not a whole lot different to lime mortar, which gets a general thumbs-up from the green community. It requires a higher temperature – and hence more energy – to manufacture, and emits more CO2 in the process, but it also absorbs CO2 when it sets, a fact not always taken into consideration. It’s non-porous while lime is porous, so it doesn’t breathe, but whether that’s ‘good’ or ‘bad’ depends on the context in which you’re using it. It doesn’t bio-degrade very quickly, but then neither does rock, and its breakdown products are no less environmentally benign … It has both advantages and disadvantages which, depending on your priorities in any particular context, can tip the balance either way.
In the end, it tipped in favour for the patio floor area and the log store. The steep terrain, the effects of rainfall and the weight of rock and soil the walls of the log store will be holding back once we finish backfilling required a material with a lot of strength. Building a terrace wall out of just schist and soil in the manner of those which shape this landscape is a rare skill now, and even then walls can and do collapse with some regularity after a lot of rain. Alternatives – eg. gabions – would require a lot of rock to be brought in from elsewhere and although it’s mined close by, would still be using a lot of fossil fuel to extract and transport. Not to mention the cost comparison. So cement it was …
Practicalities – which can be as dry as (cement?) dust – aside, it’s been exciting seeing this work come together so quickly. The feeling of space I was already sensing as the first timbers of the trellis went up is now more … ummm … concrete.