What is a tie-beam bent?

A tie-beam bent (Dutch: tussenbalkgebint) is a load-bearing timber frame made of two vertical posts and a horizontal beam that runs across the width of the building and ends inside the posts. The beam does not pass through the posts but sits between them, which is where the Dutch name comes from. You find this type mainly in historic Dutch farmhouses and barns, where a row of bents placed one behind the other carries the roof.

Layout

• Posts: two upright timbers that carry the loads down.
• Tie beam: the cross beam, jointed into the posts with a mortise and tenon and secured with timber pegs (treenails). Next to the tenon there are often housings or notches in the post that enlarge the bearing area.
• Brace: a diagonal timber in the corner between post and beam, across the building. It makes the bent rigid.
• Wall plate: the longitudinal timber on top of the posts that ties the bents together along the length. It is usually supported by two wind braces per post, and by one at the gable ends.
• Brick pads: the posts often stand on brick piers, so the timber is kept out of the damp and does not rot.

Tie-beam bent or anchor-beam bent?

The difference is in how the cross beam is joined. In an anchor-beam bent the beam (or its tenon) passes right through the post, so you can see its end on the outside of the post. In a tie-beam bent the beam ends inside the post, and nothing projects on the outside.

Application

• Historic farmhouses, barns and aisled halls.
• Restoration and reconstruction of listed timber structures.
• New build in traditional timber framing where the frame stays visible.

Practical tips

• Check the pegs: pegs that have worked loose or broken, and torn-out peg holes, point to movement in the frame.
• Look at the post feet: rot usually starts at the bottom, where the post stands on the pier. Splicing in a new post foot is a classic repair.
• Leave the braces in: without braces the bent loses its stiffness. Always involve a structural engineer when altering one.

Related terms

• Timber bent examples
• Head-beam bent
• Cross bent
• Longitudinal frame
• Mortise and tenon joint
• Timber brace
• Pad foundation

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