Tightening a loose chair joint

A chair that creaks is telling you that one joint has opened. Ignoring it is the expensive option, because a loose joint grinds itself oval every time somebody sits down, and an oval mortise is a much harder problem than a loose one.

The cause is almost always the same. Old animal glue is brittle and gives up, or the timber has shrunk across its width during years of dry indoor heat. The joint itself is usually undamaged.

The wrong fix

Squirting fresh glue into the gap without taking the joint apart is the repair everybody tries first. It does not work, because the new glue lands on a face of old glue and dirt rather than on bare timber, and it buys a few months at most. Screws driven through the outside of a leg are worse: they split the timber and leave a hole that has to be plugged later.

The sequence that holds

Work on one joint at a time so the rest of the frame keeps its geometry.

1. Ease the joint apart by hand, rocking gently rather than levering, and mark the parts so they go back the same way round.
2. Clean both surfaces back to bare timber. Warm water and an old chisel used as a scraper will lift old animal glue; a modern glue may need a light scrape and a dry brush.
3. Test the dry fit. If the tenon now rattles, glue a thin veneer shim to one cheek, let it cure, and pare it until the joint pushes home with firm hand pressure.
4. Glue, assemble and pull it up with a strap clamp around the whole frame rather than a single clamp across one leg.
5. Stand the chair on a flat floor, check that all four legs touch, and leave it clamped overnight.

A chair repaired this way is genuinely fixed rather than postponed, and the whole job takes about twenty minutes of work spread across two days.