Right, the size cannot easily change I suppose, for how could you repair older houses/etc? Or use older building plans?

We (Canada) partially transitioned too, but didn't complete the building supplies part of it.

So food is all metric, roads, speed limits, distances, weights, yet wood is imperial, and tools are metric and imperial.

This makes sense, because with the US so close, and the largest trading partner, imperial cannot fully vanish in some repects, until they get rid of it too.