The Round House has 16 sides and is 10 metres in diameter. It has a basement below and an attic cupola above, both linked to the main floor by a wooden spiral staircase. The bay window is a glass prism.

The house sits on a base of dolerite stonemasonry. Some of the sixteen sides are feature walls of stone, some are of mud brick made from soil from the excavation, and others are largely glass window to let in the superb views of nearby mountain peaks. The roof is of reinforced cement render over an insulating base of sawdust and cement.

The inside of the onion-top cupola is lined with silver wattle over oregon ribs.
In the centre of the room is a curved symbol from the Japanese Edo Period meaning good luck.

The kitchen cupboards are made from a combination of timbers including:

• Myrtle,
• Blackwood,
• and Celery Top Pine.