There is a moment early in almost every project when a client points at something — a patched area of plaster, a floor tile that does not match its neighbours, a beam that has been reinforced with a steel plate — and asks whether we can hide it. Our answer is almost always no. Not because we cannot, but because we think they are asking the wrong question.

A building that has been lived in carries evidence of that life in its fabric. The patch in the plaster is there because a pipe was rerouted in 1967. The mismatched floor tile is there because the original was cracked and the house was repaired by someone who cared enough to fix it rather than leave it broken, even if they could not find an exact match. The steel plate on the beam is there because a previous owner opened up the floor plan and a structural engineer solved the problem with the most honest means available. These are not failures. They are history made physical.

The Japanese concept of kintsugi — repairing broken ceramics with gold so the repair becomes the most visible part of the object — is often cited in conversations about this, and it is a useful reference, though we are wary of borrowing too directly from a tradition that is not ours. What we draw from it is the underlying logic: that the history of an object or a building is part of its value, and that concealing that history in the name of visual tidiness is a kind of impoverishment.

What it means in practice

In the Atelier House in Porto, the granite party walls are exposed and oiled rather than plastered over. They are uneven and have been repaired multiple times over the building’s two-hundred-year life. Each repair is visible: a section of newer mortar here, a different-coloured stone inserted to fill a gap there. When the ceramicist who lives there has guests for dinner, people often spend time looking at the wall, running their hands along it. The wall has more to say than a plastered surface would.

In Rua das Flores, the painted tile dado in the entrance hall has several tiles that have been replaced at some point and do not quite match the original pattern. We considered replacing them with reproductions — it would have been possible — and decided against it. The slight irregularity in the sequence of diamonds is barely noticeable until someone points it out, and once you have seen it, it makes the whole dado more interesting rather than less.

None of this means leaving everything as found. A building that has been poorly maintained, or that carries damage rather than repair, needs work. The distinction we try to make is between traces of care — evidence that the building has been looked after over time — and traces of neglect. The former we keep. The latter we address. The judgement call is not always obvious, which is why it cannot be made from drawings. You have to be in the building, standing in front of the thing, to decide.