A while ago, I made a decision to build something substantial out of Lego. I mulled over a few possibilities - I really wanted something challenging and would look impressive when it is finished. In the end I plumped for Canterbury Cathedral - mainly because I lived in Canterbury for eight years while I was at university there.
I started building at the beginning of December last year and have been going since then (so about 2.5 months so far).
The first challenge was to pick a scale that would suit the rather restrictive ‘resolution’ that building with Lego has. Things like arches work best when there are an even number of studs to bridge. I also wanted to ensure that the scale was as precise as possible. In the end, the scale that I chose means that the whole thing fits onto 7×2 32×32 baseplates (or 224 studs long and 64 studs wide). That works out to 1.78m by 0.51m (5′10″ by 1′8″). As a scale ratio, that works out at about 1:93. The Bell Harry tower will be 1m tall (3′2″).
Owing to the size of the model, I made the decision to split it into four parts. The first part forms the west half of the nave and the two west towers. The second part forms the east part of the nave. The third part forms the four transepts, quire and Bell Harry tower. The fourth part forms the eastern end of the cathedral, including the Trinity chapel. While I am trying to make the model as realistic as possible, I have to make a few design liberties. The main omission will be the crypt - without cutting through the baseplates (or building up to ground level), this would be too difficult. Also, I have to use light grey bricks (light bluish grey to be precise!) because any more appropriate colours don’t offer enough choice regarding different bricks (I have tried to use bright colours for bricks that are purely to support my structure, such as to support the floor of the quire). And obviously, Lego doesn’t allow me to embellish the model with all the gargoyles and statues that the real thing has!
I have mostly completed the nave and western towers. I am currently working through the quire and transepts and planning out the floor plan before building upwards.
Here are some photos of the construction so far:
East end of the nave:
Nave vaulting detail:
Lots of bricks!
Building the west end of the nave:
Completed nave and western towers (notice the windows built using lots of transparent 1×1 plates):
Looking down the inside of the nave (the 1×1 round tan plates are the ‘legs’ for pews made with 1×4 panels):
Building arches across a gap of three studs is not easy!:
Prototyping the choir stalls and panelling in the quire. The stalls are built out from the walls using a stack of plates. They are held to the wall using a 1×4 brick with studs on the side and are supported at the other end by a pier with a tile on top.
The quire and west transepts are taking shape:
The whole thing as it was on 18 Jan 2009:
Current latest photo (10 Feb 2009). I am starting to plan out the floor plan of the eastern half of the cathedral. Note the two chapels to the east of the east transepts - they are offset from straight by about 30 degrees and as a result are just sitting on top of a number of tiles. They are held to the baseplate by only three studs.
Further photos as well as larger versions of the above are available from here.
So far I have worked my way through just shy of 12,000-15,000 bricks. I think that the whole structure will require something in the order of 25,000 bricks. I will update my blog with further progress over the next couple of months. Right now I am stalled waiting for another stock of 1×3 bricks 
A big thanks to all the folk on BrickLink - they will know who they are by my hoovering up of much of their stock of light grey bricks!
