The Design

Well, we've been talking mostly about building the Round Strawbale House so far, but since there hasn't been a lot of building happening lately I thought now would be a good opportunity to show the house design and talk a little about it (I hope to write detailed blog posts in the future about each of the design elements mentioned below).

As you can see from the plan that the house roof line from the top view is a regular decagon. The reason we chose this shape is that we wanted a round house but making an actual round house has it's difficulties, so we squared off the edges and chose the decagon because for the size house it gives a beam length of ~6 metres between the outer posts. Any timber above 6 metres starts to become exponentially more expensive and the bigger the span the bigger the timber cross section. There is a balance between the number of posts required and beam length.

An important design aspect of the house is the sunroom located on the north side of the house. This room covers two outer segments of the building. These two segments are different to the rest of the roof in that they only have roof cladding to just past the inner ring of posts (the overhang will be about 1.2m to shade the entrance in the hottest part of the year in January/Feburary for where we live in South Eastern Australia). This room opens into the living room, one of the bedrooms and the bathroom with the idea of using the sunroom in winter to passively heat the house. The sunroom can also be used to cool the house in summer by drawing air through the house from the south side which will have shade trees.

The next thing you will notice that all the outer walls are strawbale which have a wall thickness of 500mm, this provides a good thermal barrier to reduce heat loss in winter and heat gain in summer. The inner walls are mudbrick and will most likely be between 150mm-200mm, the idea of this is to provide internal thermal mass to keep the house internal temperature relatively stable. The outer walls are all quite curved and do not follow the roof line. This was done for aesthetics, to provide interesting nooks and crannies around the house and because I like to give myself a challenge in building. If you're going to build a round house, might as well make round rooms.


The living room and kitchen are combined into one big room (which is round) in the centre of the house. The idea of this is that the main room in the house is insulated from the outside by the other rooms except to the north which opens up into the sunroom. The kitchen will have a combustion stove that will have the capability to heat our hotwater service and to run a hydronic heating system required. If extra heating is needed then we will locate the radiators for the hydronic heating in the outer rooms. The kitchen shares a wall with the bathroom and is close to the toilet to reduce the plumbing required.

We spent a few days last week on putting up the fascia(6m x 300mm x 35mm) and are currently getting ready to put up the purlins (have got bolts, brackets and timber only need time).