The interior walls in the living spaces were finished with the same clay-manure-straw mixture used on the exterior walls. It was applied using the harling technique, with the surface then patted smooth.
Flattened cardboard boxes were nailed to the inside of the roof rafters. Old Mason jar lids were used as a washer to keep the cardboard from falling off the nails. This kept any roof materials from falling into the living space.
Oilcloth was glued to the cardboard and the ends were plastered into the sidewalls. The oilcloth and walls were finished with a coat of paint.
In the kitchen, both ceiling and the walls were covered in oilcloth. This was painted and this created a washable surface.
Originally floors were bare dirt with linseed oil applied to make the surface sweepable. Later, fir flooring was added over the bare dirt floors.