Here is the frame of an open hall house showing the main timbers although I've taken out the stairs which would have been needed to reach the upper floors. Can you see where they would have gone? You can see the doorways on either side of the building and the fire in the middle of the house. This house also has one end jettied and is a bit like Bayleaf at the Weald and Downland Museum. Houses like this would have belonged to quite rich people. 

You can drag the model around or use the arrow keys to move in and out or left and right. Pressing Shift or Ctrl or both together when you drag the mouse moves the model in different ways. You can reset it in IE by pressing F5 or CTRL + F5 in some browsers.

Here is another model , just the same except this time with the stairs and a chimney. Use the up and down arrow keys to move in and out. The left and right keys rotate the model. If you drag the model and press the CTRL key or the Shift key you can spin the model over.

As soon as chimneys appeared in many open hall and cruck houses the owners were able to put in extra floors as they didn't need so much space to catch smoke and heat from the open fire. They could also keep warm cupboards next to the chimney breast. Some people preferred to keep the large hall because it was still very impressive and it saved a lot of building work. Which would you have done?