Adrian Gibson has written research papers detailing constructive geometry in many medieval aisled barns. (See notes in the acknowledgements section).
He was kind enough to measure and prepare the following explanatory notes and diagrams for the St Barnabas Centre.

These notes are on three pages - this page, page 2 and page 3
### Constructive Geometry of the Ground Plan
of the North Barn at Thorley Hall (St Barnabas Centre)

Only a straight edge, compasses and preliminary scaled lengths are used
which can be replicated by cords in the framing yard / field.

The barn is 2 rods (33') wide and 9 rods (148'6") long (plus exterior cladding)

1. Draw a horizontal centre line.

2. Construct a right angle line (using compass arcs) passing through point O on the centre line.

3. Set a compass to 1 rod (16�') width and draw a circle centre O cutting the vertical
at A and B.

4. Where the circle cuts the centre line each side, construct further 1 rod radius circles

- continue similarly to make 4� circles (9 half circles).

5. Draw lines parallel to the centre line touching the outer exteriors each side to define
the barn's width (2 rods).

6. At A and B construct 1 rod radius circles touching at O. Where they cut the barn width lines (5. above) connect through to set out the bay intervals (1 rod), repeat for 9 bays.

These notes are continued on page 2 and page 3