20 Jahre asbn und Strohballenbau - 20 years of Straw Bale Building

S T R A W B A L E B U I L D I N G S I T E W O R K S H O P S
ROOF & WALL
It is incomprehensible to me why many straw bale builders are still uncomfortable
with the idea of insulating a roof with straw bales. Straw bale infill between 6 x 36cm
rafters is easier than filling a wall because there are no windows or openings (or only
a few). Heat rises and roofs should be insulated to at least the same standard as
walls. For 45° roofs, it is recommended to secure yourself with device (rope or
safety harness), as the surface of the bales can be quite slippery. We first plank the
underside (carpentry) with rough planks, reed stucco and clay plaster, or - without
rendering - with 4cm fire protection formwork and eco-steam brake (kraft paper).
The upper side is clad without a gap with diffusion-open sub-roof panels (UDP, e.g.
Agepan or Egger). This is followed by the rear-ventilation level and the actual
rainproof roof covering. The walls in the two straw bale houses in Ernstbrunn (left
side) and Summerau (this side) are double-post constructions. The clay/earth
rendering is plastered directly onto the straw bales, in Ernstbrunn a hand plaster
with earth from the building excavation, prepared (to cob) with straw fibres in a
cement mixer, in Summerau a ready-made clay plaster of Sand & Lehm.
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