Symptoms
- Sitting causes a sinking or shifting feeling
- Cracking sound when someone sits down
- Visible crack or splintered wood underneath
Likely causes
- CommonCracked corner block or jointCorner blocks bear a lot of stress and are a common failure point.
- CommonBroken leg mounting bracketLegs attached with a single bracket can shear off under uneven weight.
- PossibleWeak particleboard or MDF frame constructionBudget furniture often uses pressed wood that cracks more easily than solid wood.
- PossibleOverloading beyond the frame's weight ratingConsistently exceeding the intended weight capacity stresses joints over time.
What to do
- Flip the couch over or remove the dust cover underneath to inspect the frame.
- Locate the exact crack or break and clean away any splinters or debris.
- Apply wood glue into the crack and clamp it tightly, following the glue's cure time.
- Reinforce the repaired area with an L-bracket or corner brace screwed into solid wood on both sides.
- For broken leg mounts, add a new mounting plate rather than relying on the original screw holes.
- Let all glue and repairs fully cure before sitting on the piece again.
Tools and parts
- Wood glue
- Clamps
- Drill
- L-brackets or corner braces
Furniture corner brace kitSearch: “L bracket corner brace wood”
Furniture leg mounting plateSearch: “sofa leg mounting plate”
When to call a pro
If multiple joints are failing or the frame is pressed wood that's crumbling, a professional upholsterer may recommend reframing or replacement.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.