He just did the maths, and saw that the slab edge needed to be 1383 back from the cladding line, rather than 1385 as it was.

I must ask one of the seniors, who turns out to be a friend of a friend of mine.

He just did the maths, and saw that the slab edge needed to be 1383 back from the cladding line, rather than 1385 as it was.