Cracks in teak usually come from the wood moving, not from rot. Teak is a stable wood, but it still shrinks and swells a little as humidity and temperature change, and that movement can open a crack over time. Outdoor pieces see the most of this, because sun dries the surface and rain wets it again.
The right fix depends on the kind of crack, so start by sorting it out. For the wider restoration process, see restoring mid-century teak furniture.
Start by sorting the crack
Surface checks on outdoor teak
Surface checks are shallow cracks that run along the grain on the face of the wood. They are normal on outdoor teak and are usually cosmetic. Hairline checks open and close with moisture.
Leave hairline checks alone unless they bother you. A rigid filler is a poor choice here. As the wood moves, the filler cracks or pops out, and the repair looks worse than the crack did.
Splits and end checks
End checks start at the cut ends of boards, where the grain is exposed. They can grow into splits. Sealing the end grain slows them down.
A split is a crack that has opened enough to matter for appearance or strength. A split in a leg, a joint, or any other part that carries weight is structural. A surface fill won’t restore its strength, so use glue and, where needed, reinforcement such as dowels or a butterfly key. If you aren’t sure how much load a joint carries, ask a furniture repairer before you use the piece.
Cracked veneer
On indoor pieces, cracks often show up as lifted or split veneer. Re-glue or patch the veneer itself, and don’t fill the core underneath. For more on lifted veneer, see the repair section of restoring mid-century teak furniture.
What you’ll need
- Acetone, to degrease the joint. It is flammable, so use it in a ventilated space away from flames.
- Glue: a slow-cure epoxy, polyurethane glue, or Titebond III for outdoor pieces. PVA is fine for indoor veneer.
- Clamps, with scrap wood or cardboard between the clamp and the teak.
- Thin CA glue (superglue) for small cracks.
- Fine teak dust, saved from sanding a scrap board, to mix with epoxy or pack into small cracks.
- Sandpaper: 120 to 180 grit for solid teak, and 220 grit for veneer.
- Nitrile gloves and a dust mask (P2 or N95).
- Oil or sealer to match the rest of the piece.
Repair a split with glue
Glue is the right fix for a solid teak split that is still attached and needs to hold. For how glue handles splits in other woods, see will wood glue fix split wood. Open the split slightly so you can clean it and get glue inside. Don’t force it. If it won’t move, clean what you can reach.
Clean the joint with acetone
Teak’s natural oils weaken glue bonds. Clean the crack with a rag, then wipe both faces of the split with acetone. Let the acetone flash off for a few minutes, then glue within about 15 minutes, before the oils come back to the surface. Keep acetone away from flames, and work in a ventilated space.
Glue, clamp, and wipe the squeeze-out
Work the glue into the crack with a thin brush, a stick, or a syringe. Clamp with moderate pressure. Too much pressure squeezes the glue out and leaves the joint starved. Wipe off the squeeze-out while it is still wet. Epoxy and polyurethane glue are much harder to clean once they cure.
Clamping and cure times
Clamp times depend on the glue. PVA can usually come out of the clamps after about an hour. Polyurethane glue usually needs 1 to 2 hours in clamps. Most glues reach full strength after about 24 hours. Check the label for your product, since times vary.
For structural repairs, use a slow-cure epoxy with a 24-hour cure. Five-minute epoxy sets too fast to work well, and it is not as strong, so avoid it for structural repairs.
Fill small cracks and gaps
Use filler only where the crack is small and not moving. Rigid filler in a moving crack will fail. For a comparison of off-the-shelf products, see the best wood crack filler.
Thin CA glue and teak dust
For a small crack, pack fine teak dust into it and press it in. Wick thin CA glue into the dust, and sand it flush once the glue has cured. The dust helps the repair blend in.
Epoxy mixed with teak dust
For a gap that is too wide for CA glue, mix epoxy with fine teak dust. The mix tends to match the color of the surrounding wood better than most off-the-shelf fillers. Work it in, slightly overfill the gap, and sand it flush after it cures.
Reinforce wide or recurring cracks
A crack that is wide or keeps coming back may need a butterfly key, also called a bowtie key. This is a shaped piece of teak set into a recess cut across the crack, and it helps stop the crack from spreading. Cutting the recess accurately takes care. Practice on scrap first, or ask a repairer to do it.
Sand flush and match the finish
Sand the repair flush once the glue or filler has fully cured. On solid teak, start at 120 to 180 grit. On veneer, sand by hand only, at 220 grit. Teak dust is a sensitizer, so wear a mask while you sand.
Then oil or seal the repair to match the rest of the piece. Finish the whole surface, not just the repair, so the color evens out. Teak darkens with UV exposure and age, so a fresh repair may look lighter than the wood around it for a while.
For outdoor pieces, teak oil or teak sealer explains which finish to choose.
Mistakes to avoid
- Thinking teak never cracks. It does, especially outdoors.
- Filling a moving outdoor check with rigid filler. The filler will crack around it as the wood moves.
- Expecting oil to close a crack. Oil colors and conditions the surface. It does not close the gap.
- Gluing unwiped teak. Wipe the joint with acetone first, or the bond will be weak.
- Using five-minute epoxy on a load-bearing joint. Use a slow-cure epoxy instead.
Safety
- Nitrile gloves for epoxy and CA glue. CA glue can bond skin quickly.
- A dust mask (P2 or N95) when sanding teak.
- Acetone is flammable. Ventilate the work area, and keep it away from flames and sparks.
- Oily rags can self-ignite as they dry. Lay them flat to dry, or keep them in a water-filled metal can.