Diagnose the wobble correctly before fixing (best practice guide)
Before applying any fix, determine the actual cause of the wobble. Misdiagnosing the cause leads to wasted effort and recurring problems. There are three fundamentally different causes of furniture wobble, and each requires a different repair approach.
The Three Causes of Wobble
1. Loose joints -- The most common cause in wooden chairs. Joints (mortise-and-tenon, dowel, or screwed) have loosened from repeated stress, wood shrinkage, or dried-out glue. Symptoms: you can feel movement at the joint when you push on it; the joint flexes or clicks.
2. Uneven leg lengths -- One or more legs are slightly shorter than the others, usually from wear, previous trimming, or manufacturing variation. Symptoms: the piece rocks on a flat surface but the joints themselves feel tight.
3. Uneven floor -- The furniture is fine; the floor is not level. Symptoms: the same piece wobbles in one location but is stable in another; other furniture in the same area also wobbles.
How to Diagnose
- Move the piece to a known flat surface (a concrete garage floor is ideal)
- If the wobble disappears, your floor is the problem, not the furniture
- If it still wobbles on a flat surface, grip each joint individually and try to move it. If any joint flexes, you have loose joints
- If all joints are solid but the piece rocks, check leg lengths: place the piece on a flat surface, identify which leg lifts, and measure the gap with a thin ruler or feeler gauge
Matching the Fix to the Cause
- Loose joints: Re-glue, epoxy, thread-wrap, inject glue, or add brackets
- Uneven legs: Felt pads, adjustable leveling feet, shims, or trim the long leg
- Uneven floor: Adjustable leveling feet or a rubber pad under the short side
Tips
- Most wobbly chairs have loose joints, not uneven legs
- A wobble that has gotten worse over time is almost always joints loosening
- A piece that has always wobbled since purchase likely has an uneven leg or was assembled poorly
- Fix all loose joints at once, not just the worst one, since stressing one joint accelerates failure in others