The nights are drawing in here on the Isle of Lewis, I'm back to cooking up some house plans...
My aim is to design a simple house, one that takes inspiration from the vernacular here - something that requires minimum machinery and specialist expertise. Using as "green" material as is possible in our context.
Simple frame using big lumps of untreated graded 75mm x 300mm timber. Doubled up for the trusses. I need to rope in a Structural Engineer but I reckon they can handle an extensive turf roof - dead weight of around 200kg/m2. There's rarely snow here - but it's often fairly gusty.
Clad it out with MGO boards - these seem to be the bees knees and tick a lot of boxes for this build. Insulate inside with rockwool or similar. I'd like to get a good amount of thermal mass into the gable end walls somehow.
Big wrap around double skin dry stone/earth filled wall - as per Blackhouses. It's fairly low, at 1.2m high. I want to keep the overall profile low and tuck the building into the hillside.
Heavy duty liner (I've looked into geosynthetic bentonite liners as an alternative but I don't think they're cut out for roofing...) cover in turf from on site and let the grass grow!
In the future additional wee houses and structures can be added on and share the existing walls - as per Turf and Black Houses:
All sitting on a "raised earth" foundation - some form of slab/rammed earth floor, insulated with foamglass.
Electric underfloor heating (used as a dump load) and a masonry stove/oven/cooktop/water heater.