Oak roof structure — Brockweir

Joanna and Chris were building a new house on their own plot above the Wye at Brockweir, with Anthony A Davies as main contractor.

The house was designed around oak left visible from below — trusses over the main rooms, with ridge beams and purlins carrying the roof between them.

They came to us first about a balcony, which turned into a job of its own. The roof structure reached us a different way: the contractor asked us to quote it supply only.

Supply only means what it says. We cut the frame and somebody else puts it up.

The package was five raised collar trusses, nine ridge beams and eighteen purlins, cut at our workshop near Abergavenny, numbered, and delivered to site for Anthony Davies to raise.

A raised collar truss suits a room where the ceiling follows the line of the roof. The collar sits high enough to leave the space open towards the ridge rather than cutting across it, while still doing the structural job of stopping the rafters spreading.

Partway through, Joanna and Chris asked for braces in the sitting room, the main bedroom and the landing. Those went into the frame before anything was cut, which is the cheap moment to change your mind.

Three different arrangements on one house, which is worth spelling out, because it is how oak work on a new build usually happens.

The roof structure was supply only — ours to make, theirs to raise.

The balcony we designed and built ourselves, everything but the footings. That has its own page.

Later, internal beams and an oak surround to carry the extractor over the Aga were supplied the same way as the roof: made by us, fitted by others. Because they formed part of a new house, that work was zero-rated for VAT.

If you are a builder or an architect who wants the frame without the carpenters, this is what that looks like.