The word 'Ap' means "house" in the Chumash language. The average ap was 12ft to15ft in diameter, but the chief's ap could reach up to 35ft across. Their home's round shape was made by putting poles, made of willow wood, into the ground in a circular shape. The poles were then embowed to form a dome-like roof. Then, between the poles smaller saplings or branches were tied horizontally. Covering the wood frame the Chumash people placed reeds, such as bulrush or cattail. The layers of reeds overlapped the one below it, preventing water from entering.
The door way frame could be made several ways. The Chumash would use a curved piece of wood along one edge of the doorway or they may use whale bone. Woven mats called Tule mats were hung over the entrance to keep in warmth or to show that no one was home.
At the very top of the dome-shaped house an opening was left to allow air circulation and a place for smoke to exit when a fire was lit inside.
Fires were only lit inside when it was raining or was particularly cold. Otherwise, on regular days fires were lit outside for cooking.
The interior of the ap was often decorated with colorful mats upon the walls or the floor. Also within the ap platforms were built that rose above ground level. The platforms were covered with woven mats and leathers and were used for sleeping.