How to Oil, Fit and Look After a Wooden Worktop

1. Before you start

Check every board on the day it arrives

Count the boards, look at both faces and all four edges, and keep the packaging until you are happy. Do this before anything is cut or oiled: our returns policy covers unused items in their original packaging, and a board that has been cut or oiled is no longer unused. If anything is damaged, photograph it and contact us the same day.

Which side of a wooden worktop goes up?

The smoother, cleaner face is the A side and goes up. The B side may show small filled knots or sanding marks and goes down. Neither affects the strength of the board. Decide which is which before you mark out any cuts, because the best long edge should also face the front of the run.

Every board has a better face. Find it before the first cut, not after.

Give this page to whoever is fitting it

Most damage to a wooden worktop happens in its first week: unpacked before the plaster is dry, stored on its edge against a wall, fitted bare, or screwed down so tightly it cannot move. A good fitter will recognise everything below; a kitchen fitter who mostly works with laminate may not. The rules are short, so share them, and print the checklist at the end.

2. Storage and acclimatising

How should a wooden worktop be stored before fitting?

Oil it as soon as it arrives, then store it flat and fully supported, in its packaging, on battens off the floor, in a room with stable humidity. Never lean a board on its edge and never lay it straight on a concrete floor. Fit it as soon as the kitchen is ready for it.

• Flat, never on edge. Lay each board flat and fully supported, in its packaging. A board leant against a wall for a fortnight will bow.
• Off the floor, on battens. Two or three battens under the bottom board, and battens between boards if they are stacked, so air can reach every face. Boards laid straight on a concrete floor take up moisture from one side only and cup.
• Indoors, in a room with stable humidity. Not a garage, not a conservatory, not against a radiator.

Stack boards flat with battens under and between them so air reaches both faces. Never lean a board on its edge.

Do not unpack the boards until

1. The kitchen's humidity has settled: the heating is on as it will be in normal use and the room is dry.
2. All carcasses and cabinets are built, fitted and level.
3. Building dust and debris have been cleared. Grit under a board marks it, and dust in the air lands in wet oil.
4. Wet trades are finished and have had time to dry out.
5. Fresh plaster has dried right through, which means allowing at least six weeks.

A newly plastered room can hold a remarkable amount of water, and a bare board sitting in it will drink from one side. This is the most common reason a perfectly flat board arrives at the fitting day bowed.

How long should a wooden worktop acclimatise?

Once the room is dry and the cabinets are in, let the boards lie flat in the kitchen, still wrapped and on battens, for 48 to 72 hours before you cut anything. That lets the timber settle to the room's humidity so the board you cut on Monday is the same size on Friday.

3. How to oil a wooden worktop

What is the best oil for a wooden worktop?

A hardwax oil. The manufacturer of our boards specifies Osmo TopOil, a food-safe hardwax oil that soaks into the timber and cures hard inside it rather than forming a film on top. That is why an oiled worktop can be repaired on the spot years later: clean the patch, brush on more oil, done. It comes in clear and tinted finishes, listed below.

Osmo TopOil colours and finishes

How many coats of oil does a wooden worktop need?

An unoiled board needs two thin coats on every face and edge before fitting, a third on end grain and cut-outs, and two thin coats on the top after fitting. A pre-oiled board skips the pre-fitting coats on its faces but still needs every cut edge oiled and one to two coats on top after fitting.

The top face of an unoiled board ends up with three to four thin coats over its first fortnight. That is normal for hardwax oil, which is applied sparingly; a thick coat does not protect more, it just stays tacky.

How do I oil a wooden worktop?

Thinly, along the grain, on a clean dry board, with 8–10 hours between coats in a ventilated room. Roller or brush for the first coat, a pad or lint-free cloth for the second, and wipe off anything still sitting wet after 20–30 minutes. Do every face, every edge and every end grain, not just the top. Osmo TopOil drying time is 8–10 hours between coats and 2–3 weeks to a full cure.

1. Test a patch first. Oil a corner of the underside, or an offcut, and let it dry. Check the colour, and if you have several boards check they match each other. This matters most with tinted oils and with Natural Matt on pale timbers.
2. Start clean, dry and dust-free. Boards come sanded to 120 grit and need no further sanding. Vacuum and wipe the board; sweep the room. Do not oil a board that has been standing in a damp room.
3. Stir the tin and apply the first coat thinly, along the grain. Use a short-pile roller or a flat brush. Thin is the instruction that matters: the surface should look wet, not flooded. Do the underside, all four edges and every end grain, not just the top.
4. Wipe off anything still sitting wet after 20–30 minutes. Oil that pools on the surface will not cure properly and stays sticky for days.
5. Leave it 8–10 hours in a ventilated room. Longer in a cold one. Osmo's figure assumes a normal room temperature; a chilly extension in January can double it.
6. Second coat with a pad or lint-free cloth. Thinner still. This is the coat that seals the grain the first coat raised.
7. Third coat on end grain and cut-outs. End grain drinks oil like a straw; the sink cut-out is where every failed worktop failed first.
8. Dry, then handle with care. The board can be handled and fitted the next day, but the oil takes 2–3 weeks to cure fully.

The oiling timeline for an unoiled board

4. How much oil to buy

How much oil do I need for a wooden worktop?

Allow one 500ml tin of Osmo TopOil per 3m board, or one tin per two 2m boards. A typical three-board kitchen needs two tins. That covers two coats on all six faces of each board, with enough spare for the third coat on cut-outs and the coats after fitting.

Osmo rate TopOil at 30 m² per litre for a single coat on smooth, sanded timber, so a 500ml tin does 15 m² once. The figures below count all six faces of the board, because all six get oiled, and two coats on each. End grain and cut-outs take more, so round up.

The manufacturer's own rule of thumb is one 500ml tin per 3 linear metres of worktop, and the table agrees with it: a 3m board needs just over half a tin for two coats on every face, which leaves the rest of the tin for the extra coat on the sink cut-out and the coats after fitting. Buy one tin per board of 3m or longer, one tin per two 2m boards, and you will not run out on a Sunday.

5. Fitting the worktop

Tools you will need

• Router with a straight cutter and a worktop jig for every cut-out and joint
• Circular saw with a guide rail, or a fine-tooth blade and a clamped straight edge, for cutting to length
• Masking tape along cut lines to stop the top face splintering
• Drill, 8–10mm bit for oversized fixing holes, and a countersink
• Slotted L-brackets, round-head screws and large washers
• Worktop bolts (three per joint), a 10mm spanner and a biscuit jointer or biscuits
• Clamps, battens and 4–5mm packers
• Low-modulus clear silicone, mould-resistant silicone for the sink, end-grain sealer
• Moisture barrier for above appliances, and a solid wood end cap if there is a range cooker
• Oil, roller set, pads and lint-free cloths, plus a dust sheet for the boards

How big should the expansion gap be?

Leave 4–5mm between every worktop edge and any wall or fixed unit it meets, and above all along the back edge against the wall. Hold the gap with thin packers while you fix the board. An upstand, tiles or a bead of flexible silicone will cover it, so it never shows, but the board needs it to move.

Pushed hard against a wall, a board that takes on summer moisture has nowhere to go and lifts or splits instead. The upstand that hides the gap is fixed to the wall, never to the worktop, so the board can move behind it.

Section through the back of a run: the board stops 4–5mm short of the wall, the upstand covers the gap and is screwed to the wall, and slotted brackets let the board move.

How do I fix a wooden worktop to the cabinets?

With slotted angle brackets only, a round-head screw sitting mid-slot in the slot that runs across the width of the board, snug but not clamped tight. On solid-top cabinets, drill an oversized 8–10mm hole through the carcass and screw up through it with a large washer. Never screw the carcass straight into the board, never glue it, never use fixing blocks.

• Slotted angle brackets only, with a round-head screw sitting in the slot that lets the screw slide across the width of the board, because across the grain is the direction the timber moves. The unslotted brackets packed with many cabinets will not do; leave them in the box.
• Solid-top cabinets, or ones that can only be fixed through a cross rail: drill an oversized hole of 8–10mm through the carcass top and screw up through it with a large washer under the head. The washer holds the board down while the oversized hole lets it move.
• Never screw straight through the carcass into the worktop, never glue it, and never use fixing blocks. A rigidly fixed board splits along its length the first winter the heating goes on.
• The upstand is fixed to the wall, not the worktop. It covers the expansion gap and hides any shrinkage. Where tiles or silicone will cover the gap you do not need one.

Seen from underneath: the bracket's slot runs across the grain, so the screw can slide as the board moves across its width.

Heat, steam and damp

• Range cookers and freestanding ovens: leave a 30mm gap all round, and fit a solid wood end cap to the worktop edge that faces the cooker so the end grain is protected from the heat.
• Dishwashers, washing machines, tumble dryers and microwaves under the worktop: fit a moisture barrier to the underside of the board above them. These appliances vent heat and steam upward, and a bare underside above a dishwasher will cup within a season.
• Brick, block or masonry: never fix a board straight onto it. Fit timber spacers 6–10mm thick on a damp-proof membrane, so the board sits on an air gap.
• Overhangs: 200mm is the most a board will carry unsupported. A breakfast bar that projects further needs legs or heavy-duty brackets.

Either side of a range cooker: a 30mm gap all round and a solid wood end cap on the edge that faces the heat.

If a board has bowed before fitting

It happens, usually because a board was stored on edge or one face was left bare, and it is fixable. Fix the back edge to the cabinets along its full length first. Then pull the board down slowly with clamps and battens, a little at a time, and finally screw the front edge down through the brackets. Give it one to two weeks to settle flat. A board bowed more than a few millimetres over its length is worth a call to us before you fit it.

6. Cutting, sinks and joints

How do I cut a sink or hob hole in a wooden worktop?

Mark it out from the template supplied with the sink or hob, check it twice, then rout it on the bench with a jig, taking the cut in passes of around 10mm. A jigsaw is for rough waste well inside the line only. Oil every cut edge immediately, two to three coats, before the sink goes anywhere near it.

• Use the template supplied with the sink or hob, mark it out, and check it twice. Our returns policy cannot help with a board cut in the wrong place.
• Cut-outs are bench-cut with a jig and a router, never a jigsaw. Take the cut in passes of around 10mm; the router will tell you if you push it.
• Drainer grooves must be machined by someone who has done them before, angled so water runs back to the sink. Water sitting in a flat groove is the classic cause of a split around a drainer.
• Oil every cut edge immediately, two to three coats, while the board is still on the bench. This is the single most important step in the whole job.

Sealing the sink

Once the sink is in, run mould-resistant silicone under the rim and around the cut edge, and pay particular attention to the underside, which is where water finds its way in and where nobody looks. An inset sink sitting on top of the board is the straightforward choice in solid wood; an undermount sink is possible but leaves the cut edge permanently wet and is a job for a fitter who has done it before.

Section through an inset sink: three coats of oil on the cut edge first, then silicone under the rim and along the underside.

How do I join two wooden worktops?

With a square butt joint: seal the end grain on both sides, align the boards with biscuits, run a light bead of clear low-modulus silicone just below the top surface, and pull the joint up with three worktop bolts. Mitres belong only where a rounded front edge forces a short hockey-stick return.

• Butt joints, cut square, are the right joint for wooden worktops. A mitred joint only belongs where a rounded front edge forces a short hockey-stick return, and that return must not run past the 10mm radius of the edge.
• Seal the end grain on both sides of the joint before assembling it, then align the boards with biscuits.
• Run a light bead of clear, low-modulus silicone along one side of the joint just below the top surface, pull it up with three worktop bolts, and wipe off the surplus at once.
• Follow the hob manufacturer's clearance instructions for the cut-out, and keep the joint out of the hot zone beside a hob where you can.

A corner joint from below: three bolts tightened evenly, biscuits to keep the faces flush, sealed end grain and a bead of silicone.

7. After fitting: the first three weeks

With the boards in, give the top face its final coats: two thin coats on an unoiled board, one or two on a pre-oiled one, 8–10 hours apart, with the room ventilated. Then treat the surface gently while the oil cures.

• You can use the kitchen from the next day, but for 2–3 weeks wipe spills as they happen, do not leave wet cloths, kettles, draining racks or plant pots standing on the surface, and do not scrub it.
• Expect to re-oil the working areas, around the sink, either side of the hob and under the kettle, at about 3–6 months. The protection builds up over the first year as each thin coat adds to the last.
• After the first year, the water test decides. Most kitchens need a coat once or twice a year; a busy family kitchen with a wooden draining area needs the sink zone doing more often than the rest.

How do I know when a wooden worktop needs re-oiling?

Flick a few drops of water onto the board. If they bead and sit proud, the oil is doing its job. If they soak in and darken the timber, that patch needs a coat. Do it before the surface looks dull, not after.

The water test takes ten seconds and tells you everything. Beads: leave it. Soaks in: one thin coat with a pad.

How do I re-oil a wooden worktop?

Clean it, let it dry completely, then rub one thin coat of the same oil in with a pad along the grain, wipe off any surplus after 20–30 minutes and leave it 8–10 hours. No sanding is needed unless the surface is marked. A worn patch by the sink can be done on its own; the whole top does not need redoing every time.

1. Wipe the area with a damp cloth and a drop of washing-up liquid, then let it dry for an hour or two.
2. Pour a little oil onto a pad or lint-free cloth, not onto the board, and rub it in along the grain in a thin, even layer.
3. After 20–30 minutes wipe off anything still glistening. What is left should look damp, not wet.
4. Leave it 8–10 hours with the window open. Use the surface gently for a day or two while it hardens.

8. Everyday care and maintenance

How do I clean a wooden worktop?

With a damp, not wet, lint-free cloth, warm water and a drop of washing-up liquid, or a spray made for oiled wood such as Osmo's AntiBac cleaner. Wipe along the grain and dry it off. Never use bleach, cream cleaners, scouring pads or multi-purpose kitchen sprays: they strip the oil and leave the timber open to water. If a scourer does get used, re-oil the patch.

The short version

9. Problems and how to fix them

How do I sand and re-oil a wooden worktop?

Sanding takes a tired worktop back to bare timber so it can be oiled as new: an orbital sander with 80 grit to remove the old surface and marks, 120 grit to smooth it, 150–180 grit to finish, always along the grain, then vacuum, wipe and apply two thin coats of oil 8–10 hours apart. A whole run takes an afternoon.

1. Clear and clean. Everything off the worktop, tape off the sink rim and hob edge, and wipe the surface down so grease does not clog the paper.
2. 80 grit along the grain. An orbital sander takes off the old oil, scorches, rings and knife marks. Keep it moving and keep it flat; the edges and corners are done by hand with a block.
3. 120 grit, then 150–180 grit. Each pass removes the scratches of the one before. Stop at 180: any finer and the timber is too closed for the oil to soak in.
4. Vacuum, then wipe with a barely damp cloth. Let the surface dry, then run your hand over it. Any rough patch gets a final pass with 180.
5. Two thin coats of oil, 8–10 hours apart. Exactly as for a new board: thin, along the grain, surplus wiped at 20–30 minutes, a third coat on cut edges. Gentle use for 2–3 weeks while it cures.

10. The fitter's checklist

Seventeen lines that cover every rule on this page. Print it, tick it off, leave it with the customer.

• Boards counted and checked on delivery, packaging kept until signed off
• A side identified on every board, best long edge to the front
• Room dry, fresh plaster given six weeks, cabinets fitted and level
• Boards stored flat on battens, never on edge, and acclimatised 48–72 hours
• Two thin coats on every face and edge before fitting (pre-oiled: cut edges only)
• Third coat on all end grain and cut-outs
• 4–5mm gap at every wall and fixed unit, held with packers
• Slotted brackets only, screw mid-slot across the grain, snug not tight
• Oversized 8–10mm holes and washers through any solid carcass top
• Moisture barrier fitted above dishwasher, washing machine, dryer or microwave
• 30mm gap and solid wood end cap at any range cooker
• Cut-outs routed with a jig; cut edges oiled the moment they are made
• Sink sealed with mould-resistant silicone under the rim and underside
• Joints: end grain sealed, biscuits, silicone bead, three bolts pulled up evenly
• Upstand fixed to the wall, never to the worktop
• Two thin coats on the top after fitting; oily rags laid flat outside or soaked
• Customer told: gentle use for 2–3 weeks, water test, first re-oil at 3–6 months

11. The kit you need

Everything below is stocked alongside the worktops, so it can go in the same basket and arrive on the same delivery.

Slotted brackets, worktop bolts, biscuits, a moisture barrier and low-modulus silicone are standard items from any builders' merchant.

12. Questions we get asked