Sand, stain if you like, then apply two or three coats of varnish, drying and light sanding between each coat.
VW-01Prepare the roomOpen windows for ventilation, oil-based varnish gives off strong fumes and needs airflow. Lay dust sheets under and around the woodwork and move furniture or curtains out of spatter range. Take off door handles, hinges pins or hooks where you can, or mask them with tape.
VW-02Give the wood a final sandSand along the grain with 240-grit sandpaper until the surface feels smooth and even all over. This opens the grain slightly so stain or varnish takes evenly. Wipe off all dust with a tack cloth or a barely damp lint-free cloth before you go any further.
VW-03Test the product firstWood takes stain and varnish differently depending on species and grain, so never go straight in on the visible surface. Brush a small patch onto an offcut, or a hidden spot such as the back of a skirting board, and let it dry fully. Check the colour and sheen match what you expected.
VW-04Apply wood stain, if you're using oneStir the stain thoroughly, it settles at the bottom of the tin. Brush it on along the grain in long strokes, working in small sections so you can wipe back excess before it dries patchy. Leave to dry fully — check the tin, most stains need 4-16 hours depending on type and room temperature. Skip this step if the varnish alone will give you the colour you want.
VW-05Stir and apply the first coat of varnishStir the varnish gently, don't shake the tin, shaking whips in bubbles that show up on the dried surface. Load the brush lightly and apply in long strokes with the grain, working end to end without going back over areas that are starting to tack off. Leave to dry for the time stated on the tin, roughly 6-8 hours for oil-based, 1-2 hours for water-based.
VW-06Leave the first coat to cure fullyKeep the room ventilated and don't disturb the surface while it dries. Touching or sanding a coat before it's properly hard will lift it straight off. Keep pets, kids and foot traffic away from the woodwork while it cures.
VW-07Denib between coatsLightly sand the dried coat with fine 320-400 grit paper, just enough to knock off raised grain or dust specks. You're smoothing, not stripping the coat back. Wipe away every trace of dust with a tack cloth before the next coat goes on, any dust left behind gets sealed under the next layer.
VW-08Apply the second coatBrush it on the same way as the first coat, working with the grain in long strokes. Two coats is the minimum for most interior woodwork such as skirting and architrave. Leave to dry fully before deciding whether you need a third.
VW-09Apply a third coat on heavy-wear surfacesDoors, handrails and window sills get knocked and handled constantly, so give them a third coat for durability. Denib lightly again first if more than 24 hours have passed since the last coat. Skirting boards usually manage fine with two coats and don't need this step.
VW-10Clean your brushes and toolsFor water-based varnish, wash brushes in warm soapy water until the water runs clear. For oil-based varnish, work white spirit through the bristles in a jam jar first, then finish with soap and water. Reshape the bristles with your fingers and leave the brush to dry flat.
VW-11Dispose of rags and tidy up safelyOil-soaked rags can heat up on their own and catch fire if left screwed up in a bin. Lay them flat outdoors to dry fully, or soak them in water in a metal lidded tin, before you bin them. Air the room until the smell clears, then refit any handles or hardware you removed earlier.