Hallmark LibraryUmeå, 2024

Hallmark Library is a cross-laminated timber library on the bank of the Ume River, three storeys under a stepped roof that pulls northern light deep into the reading rooms. It replaces a 1970s branch library on the same plot and serves a city where, for half the year, the reading room is also a warm public living room. The structure is left exposed inside, so every column, beam and panel can be read, measured and, when the time comes, replaced or reused.

We scanned the site before demolition and again at every structural stage, 318 million points in all. Two weeks before the screed was due, the scan of the mezzanine showed one bay sitting 11 millimetres below the model, more than the floor finish could hide. The cause was a single support bracket fixed one hole too low. It was corrected, the bay was rescanned the same afternoon and the floor went down level, a fortnight before opening rather than a year after it. Since then 412 sensors report deflection, facade moisture and indoor climate to the model every fifteen minutes.