Oak roof trusses — Trellech

Debbie got in touch about an extension at the Lion Inn.

The pub needed a dining hall of its own — more covers, and room to take larger events rather than turn them away. The new space was to be open to the roof, so whatever went in overhead was going to be looked at by everyone sitting under it.

She already had a builder on board and a design from her architect. What she wanted from us was one thing: the oak trusses, made to that drawing.

The design was the architect's and the builder's, not ours. On a supply-only job like this we cut to the drawing we are handed, and our consulting engineer checks the frame before we cut it, as on every frame we make.

What the drawing called for was a raised collar truss. The collar sits high, which is what opens the room up — you get the height of the roof rather than a tie beam cutting across at head level. It also puts the load somewhere more awkward than a lower collar would.

Where the principal rafter meets the tie beam, that joint goes into tension. Oak is not at its best in tension, and it is the pegs rather than the timber that set the limit — an oak peg will take a great deal of compression and comparatively little pull. So on a raised collar truss that joint needs reinforcing, and here it carries hidden steel. None of it shows once the truss is standing.

It is worth knowing if you are pricing oak trusses against softwood ones. The joint that decides whether a raised collar truss stands up is not the one you can see.

Supply only. We cut the trusses at our workshop near Abergavenny and delivered them.

We spent time on site with the builder's team, showing them how a truss goes together — what order the pieces assemble in and what to watch for — and they took it from there.

Completed 2022.

A few years after the job we held the Foxtail Oak team Christmas meal here, so the lads could sit and eat under a roof they had cut themselves. Most of the people in these photographs are our own team.