Stone plinths completed and rafters are go – Natural Building is great!
This week has been an exciting one, with the rounded form of the building emerging, down from the reciprocal roof and up from the stone wall. Now the shape and scale of the inner spaces can be imagined much more vividly.
Wall, plinths and insulation:
The week started with the stone wall and plinths being finished – a whole team effort with scavengers looking for the perfect stone for each place, rolling the biggest stones across site on logs. Water levels and string lines were used to make sure the walls were level the whole way round. It felt like a giant game of 3D Tetris, but with no straight lines adding to the challenge. The walls were covered with hessian and jute to stop the lime mortar from drying out too quickly, and were wetted down at intervals. We also began to consolidate the lime mortar, pressing it back where smalls cracks appeared and mottling it with a brush to create a neat finish and increase the surface area, allowing it to dry out evenly.
Once the outer and inner skins of the external wall were finished, the gap was filled with Foamglas an insulation material made from recycled car windscreen. It was chosen for this build as it consists of >60% post-consumer recycled glass, and is incombustible, impermeable to moisture and load bearing. It is also free of CFCs HCFCs HFCs and other pollutants and is long lasting.
External posts and wall plate:
Once the wall was finished, construction began of the base plate that will support the straw bales and external posts. This wall plate looks like a mini train track running on top of the stone wall. Each piece of this track was duplicated as it was made to form an identical track to run along the top of the bales, to allow us to compress them.
The chop saw was out for a day of cutting noggings- the pieces of wood fitted between each side of the train track to give it strength and hold it together.
Word of the Week: ‘dwang’. The Scottish word for nogging.
Other students constructed posts that were then fitted vertically to the base plate, and topped with beams. Once these were up, the boundary of the building became clear and it really felt like we were building up and out!
The final day of this week was rafters day. Round wood rafters were fitted, extending from the inner henge to the beams of the outer wall. This involved a team of five lifting each log into place and scribing on to the log where a flat surface would need to be chiselled to let it sit on the outer beam. Then it was taken down and chiselled before being put back up in fixed in place. This was a transformative day with 12 of about 48 rafters being fitted.
The rafters will be left exposed, visible from the inside of the building. It was a great end to the week to sit beneath them and imagine all the visitors to come who will appreciate and be inspired by their beauty.
We are all getting excited for the Big Straw Bale Gathering next weekend![Post by 2018 Student Jess Makins]