Board-formed concrete, explained

Board-formed concrete is concrete cast against timber, so the grain, knots and joints of the boards are pressed permanently into the finished face. It is the reason a modern wall can feel warm rather than clinical.

How it is actually made

The formwork is the project. We build the moulds from rough-sawn Douglas fir, arranged in a deliberate pattern — usually horizontal, occasionally stack-bonded — and seal them just enough to control absorption without killing the grain. Too much sealer and you get a flat grey wall. Too little and the boards blow out.

The pour is a single continuous operation for each panel. Any interruption shows as a permanent horizontal line, and there is no repairing it afterwards. This is why board-formed work is quoted by crews who have done it before.

What drives the cost

Roughly two-thirds of the price is formwork and labour, not concrete. That has two consequences worth knowing at the design stage:

• Repeating a panel size is cheap. Reusing a mould three times spreads the expensive part.
• Every unique corner is expensive. Curves, acute angles and one-off returns each need their own mould, used once.

A simple, repeated, generously sized wall is dramatically better value than a complex one of the same area.

Living with it

Board-formed concrete is porous. It will darken with rain, lighten as it dries, and pick up a patina within a year — which is the point. We seal only where the wall meets soil or is likely to be splashed with wine.

Efflorescence — a white bloom of mineral salts — is normal in the first winter and weathers off. It is not a defect, and it is worth telling clients before it happens rather than after.

Where we use it

Anywhere the wall is doing structural work and is going to be looked at every day. Board-formed Court and the terraces at The Hillside Terrace both use it for exactly that reason: they are retaining walls first, and the finish is what stops them feeling like engineering.