We were visited by Lauren and Phil this week, who were very modest about their earth plastering knowledge but turned out to have considerably more experience than we do. They rustled up some plaster test patches on a couple of spare bales, and we (well Phil) got to work mixing the first ‘proper’ coat of plaster, which is essentially a straw heavy scratch coat over which our finish coat will be added. Despite it being a cold morning he was straight in there with bare feet –
and was watched closely by Lyra, who clambered up onto a bag of sand to see if she could be of help –
Pretty soon we had the first of our window seats plastered – the mix was 1 clayey soil, 2 sand, and some finely chopped straw, left from shaving the bale walls. The hardest part of the operation turns out to be grading the clay, which involves pushing it through wire mesh to take out the stones.
This weekend we’ll be tackling the first of the walls, and experimenting with tests for our finish coat of plaster..
You never cease to inspire me.
You’re very kind Dave. Necessity is most definitely the mother of invention around here, and being able to make plaster from mainly free materials is just too good an opportunity to pass up.
It’s looking really good, do you need a certain temperature for the clay to set? We are using lime plaster on our project but the weather is now a little chilly for it.
No I don’t think so Anne, although I wouldn’t risk exposing it to frost or really low temperatures. The thin clay slip layer took 3 days to dry, the first proper plaster coat will likely take a couple of weeks. I lime plastered some of the stonework earlier in the year and although it stopped being soft within a week, it took several months for it to go really hard. Again you need to protect it from freezing temperatures. Our lime-hemp plaster took 2-3 months to set properly, but it was onto really damp walls and that would be quicker on a dryer substrate I reckon.