How do I fix veneer that is lifting or bubbling on furniture?

Veneer is a thin sheet of real timber glued to a cheaper substrate, and when it lifts the fault is nearly always the glue line rather than the veneer. That matters because glue lines can often be repaired invisibly, and because the repair depends entirely on which glue is under there — which is usually decided by the age of the piece.

What you'll need

• Household iron and a clean cotton cloth
• Wood glue and a syringe or a thin blade
• Sharp craft knife
• Clamps or heavy weights and a flat caul
• Greaseproof paper or cling film, to stop the caul sticking
• Veneer offcut or a donor piece, for a patch (optional)

Step by step

1. Work out roughly how old the piece is.Pre-war and much mid-century furniture uses animal glue, which is reversible with heat and moisture. Anything from the last few decades is likely to be a PVA or urea glue, which is not — that needs new adhesive.
2. Try heat first on older furniture.A clean damp cotton cloth over the lifted area and a medium iron held on it for ten to twenty seconds at a time. The old glue softens. Press the veneer down, then weight it flat with a board and greaseproof paper between, and leave it a full day.
3. Slit a bubble along the grain, do not cut across it.One clean cut with a sharp knife following the grain direction. A cut along the grain disappears; a cut across the grain is visible forever.
4. Work glue in through the slit.A syringe, a thin palette knife or a piece of card. Enough to wet both surfaces and no more — excess glue swells the veneer and squeezes out through the joint.
5. Press from the middle outwards.Work the excess towards the slit and wipe it. Trapped glue under a re-laid bubble makes a hard lump that shows in raking light.
6. Clamp with a flat caul and give it time.A flat board across the repair with greaseproof paper or cling film underneath so it does not stick, then clamps or heavy weights. Full cure time, not an hour.
7. Re-lay a lifted edge with tape as the clamp.Edges are awkward to clamp. Glue, press, then strap masking tape tightly across the edge and around, pulling the veneer down. Leave overnight.
8. Patch a missing piece with matching veneer.Cut the damaged area into a simple shape with grain-parallel sides, cut a patch slightly oversize from matching veneer, glue and weight, then pare flush and finish. A diamond or boat shape hides far better than a rectangle.
9. Check the substrate before any of this.If the board beneath is chipboard that has swollen from water, the veneer is lifting because the surface under it has failed. There is nothing to glue it back to and the panel needs replacing.
10. Finish the repair last.Fine abrasive with the grain, then wax, oil or a matching finish blended out from the repair. Colour with a spirit stain or a touch-up pen before the finish, not after.

Tips

• Test the heat method in a hidden corner first. Too hot and too long will scorch the veneer or blister the finish.
• Do not sand veneer with anything coarse or with a machine. It is often well under a millimetre thick and it goes through to the substrate in seconds.
• For a bubble that will not stay down, prick it with a pin and press — sometimes it is trapped air and moisture rather than a failed glue line.

Common mistakes

• Cutting a bubble across the grain — The cut line stays visible permanently. Always follow the grain, and use the sharpest blade you have.
• Flooding the repair with glue — Excess swells the veneer, squeezes out over the finish and dries as a hard ridge. A thin film on both faces is what glues.
• Sanding a veneer repair flat with power tools — Veneer thickness is often 0.6mm or less. A sander goes through it before you have noticed.
• Gluing veneer back onto swollen chipboard — The substrate has failed. The veneer has nothing sound to bond to and the repair lifts again.

If it doesn't work

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