How do I oil a new oak worktop before it goes in?

A solid timber worktop moves with the moisture in the air, and it moves differently on a sealed face from an unsealed one. Oil the top and leave the underside bare and the two faces reach equilibrium at different rates, so the board cups. Everything else about worktop finishing — the number of coats, the extra work around the sink — follows from that single principle: finish it evenly, all over, before it is installed.

Safety

What you'll need

• Worktop oil or hardwax oil suitable for kitchen use
• Lint-free cloths and an applicator pad
• Fine abrasive, and a random orbital sander
• Trestles or a bench so the worktop can be turned over
• A second pair of hands for turning the boards

Step by step

1. Let the worktop acclimatise in the room first.Bring it into the kitchen, lay it flat on battens with air able to circulate around it, and leave it for the period the supplier specifies — commonly a week or more. Finishing and fitting a worktop that has not acclimatised is a common cause of gaps, cupping and splits later.
2. Do all the cutting, jointing and cut-outs before you oil.Every cut you make afterwards exposes bare timber, and the sink and hob cut-outs are precisely where water and heat will attack. Machine everything first, then finish the completed piece.
3. Sand to the grit the oil specifies, evenly.Usually somewhere around 120 to 150 grit for a worktop oil — check the tin, because sanding finer closes the grain and stops the oil penetrating. Work through the grades without skipping, sand with the grain, and vacuum thoroughly afterwards.
4. Oil the underside and the edges first.Turn the board over and do the back, both long edges and both end grains before the top. It is the step people skip and the one that keeps the board flat. End grain absorbs far more than the faces and should get extra coats until it stops drinking.
5. Give every cut-out edge serious attention.The exposed timber inside a sink or hob cut-out, and the underside around it, sees more water than anywhere else in the kitchen. Oil those surfaces thoroughly — three or four coats — including the underside for a good margin around the aperture.
6. Build the coats on the top, thin and wiped back.Apply thinly, let it soak for the time on the tin, then wipe all excess off before it starts to set. Let each coat dry properly. Most worktop oils want three coats minimum on the working surface, and the area around the sink benefits from more.
7. De-nib between coats if the grain has risen.The first coat usually raises the grain slightly. Once it is dry, a very light pass with a fine abrasive or an abrasive pad, then a thorough clean, gives a much better feel on the finished surface.
8. Fit it, then oil any site cuts immediately.Scribing to a wall or trimming to length on site exposes fresh timber. Oil those cut edges before the worktop is fixed down, and seal around the sink and taps properly once it is in.

Tips

• Keep a note of the product used and buy a spare tin. Re-oiling with the same product is straightforward; changing products later is not.
• The first few weeks are when a new worktop is most vulnerable. Give it extra coats around the sink and be strict about standing water until it has fully cured.
• Never let a solid wood worktop sit with water standing on it, even fully finished. A dishcloth left on the surface overnight is the most common cause of a black mark.

Common mistakes

• Oiling only the top surface — The underside then exchanges moisture with the air at a different rate, and the board cups, twists or splits. All six faces get the same treatment.
• Not oiling inside the sink cut-out — That is the wettest timber in the kitchen. Bare end grain there swells, blackens and eventually rots.
• Fitting first and oiling in situ — You cannot reach the underside or the edges, and the finish is uneven from the start. Finish it on trestles, then fit it.

Keeping on top of it

• Wipe up spills immediately and never leave standing water or a wet cloth on the surface (Daily)
• Re-oil the whole surface, and the area around the sink more often (Every few months initially, then as the surface tells you)
• Sand out and re-oil any water marks or black spots before they deepen (As they appear)

Questions people ask