We were given the brief from our clients to design an annexe to an existing straw bale house that we had built in 2017. The new build, whilst connected to the original dwelling, would also act as a separate self contained house. The two bedrooms both have mezzanine beds that maximise the space and height of the building. A open plan living space has a wood burning stove and south facing glazing to maximise solar gain.  A small bathroom also leads off the main room, with a tadelakt finished shower and compost toilet. The whole building is built with natural and sustainable materials, a timber framed construction insulated with sheeps wool and wood fibre insulation. Externally the building is clad with UK grown and milled Western Red Cedar and internally finished with clay plaster. The bed frame and windows are constructed from locally sourced oak. An earth floor was installed with underfloor heating installed within it, utilising clay taken from the site. The contemporary and clean design contrasts well with the existing straw bale house, highlighting how eco buildings can take many different design forms.