Construction details

In this section we cover some basics on:

• external walls
• internal walls
• roof
• floor finishing

external walls – construction follows the tried and tested ‘earthship’ rammed earth wall building technique using tyres as formers for the rammed earth.  Around 150 tonnes of rammed earth is used in the external walls. The result is a wall which is indestructible.  The rammed earth is also enclosed in 100mm of underground insulation which acts as a ‘blanket‘ enabling the walls to act as giant storage heaters for the building.  We chose foamglas as the main underground insulation.  Although expensive, this board insulation is made from 80% recycled glass and is completely stable indefinitely.  Damp proofing is achieved using visqueen ecomembrane, providing a permanent 0.5mm barrier around the entire walls and under the floors.

internal walls – constructed from solid upright timbers bolted to the floor and ceilings.  One side is skinned with fermacell, providing a very strong and stable structural ‘plasterboard’ made form recycled paper.  The walls are infilled with lime using a shuttering technique.  Although very time consuming, the result is a 90mm thick solid wall that provides both thermal mass and acoustic insulation between rooms.  It also provides an attractive timber and lime face to one wall of the bedrooms.  We also built external and internal bottle walls which provide beautiful lighting effects in sunlight and when lit at night.  Tips on building these are in this short clip:

ROUGH CUT FROM BUILDING

BOTTLE WALL NAVIGATOR VIDEO – INSPIRATION TO DO STUFF

roof - the main roof structure comprises 23 ibeams specified and supplied by Finn Forests.  These lock onto the front ‘kerto‘ front face beam with heavy duty simpson joist hangers.  The kerto comprises 2 x 90mm beams that bolt together and lock onto the ‘heartwood’ douglas fir uprights that support the roof and the doorframes.  Between each ibeam we fitted 330 mm of high performance ‘non itch’ eco insulation from YBS Insulation.  This was selected because it is manufactured from recycled plastic  bottles.  A heat reflecting vapour membrane called dupont airguard is fitted above the plasterboard of the ceilings and the roof void is vented at the top.  The roof covering is TPO supplied by Flag UK, which is suitable for potable drinking water collection, versatile and very durable.  The rotunda was slated by a local artisan and we incorporated salvaged copper for guttering and capping.  We also used sheeps wool insulation from Second Nature.

floor finishing – the final floors are hand poured earth cement floors which are sealed with penetrating hard oils.  Each room uses a different natural pigment from either Morroco or Zanzibar.  The earth and pigment gives character to each room, while the oils and cement makes the floors extremely hard wearing.  The kitchen and bathrooms are exceptions with large limestone slabs fitted straight on top of the concrete sub floor.  This is the same limestone as is used to form the whole of the outside terrace.