Why original boards deserve rescuing

There is a particular pleasure in lifting a tired old carpet and finding the original floorboards still in place beneath it. In cottages and mews houses, those boards are usually pine — wide, slow-grown stuff with a tightness of grain you simply cannot buy new. They have spent a century or more being walked on, and the surface has taken on an amber patina that no stain can fake. Sanding them back and sealing them is one of the most rewarding jobs you can do in a period home, and it costs a fraction of laying a new floor.

It is worth being realistic from the outset. Original boards will not look like a factory-finished oak floor, and that is the point. They will have knots, nail shadows, patches of filler and the odd board that is beyond saving. Treated as a job of repair rather than replacement, though, they will outlast anything you could put down over them.

Reading the floor before you sand it

Before you hire anything, spend an afternoon inspecting. Walk the whole room slowly and listen. A gentle bounce underfoot usually means a loose board rather than a failing joist, but a deep, springy dip is a warning sign worth investigating from below if you can.

• Movement and squeaks: punch old nails down with a nail set rather than pulling them, then re-fix with countersunk screws through the joists.
• Gaps: some springing is normal as boards dry out seasonally. Look for gaps that run the length of the room, which suggest shrinkage rather than damage.
• Previous finishes: wax and polish come up readily. Varnish, bitumen and old paint need more aggressive treatment and may clog your abrasives quickly.
• Staining and damp: dark tide marks under a radiator or around a doorway often mean a slow leak. Fix the cause first, or the stain will simply reappear.
• Woodworm: small flight holes are common and often historic and inactive. Fresh dust beneath the holes means it is live and needs treating before you seal anything in.

Repairs that make the difference

Where a board has been cut away for old pipework, or has rotted near a sink or a drafty external door, replacement is usually better than filler. Reclaimed pine of a similar age and width is the ideal match, and a specialist salvage yard will often let you pick through a pile to find a close profile. Failing that, a new board can be stained and distressed to blend in — a little too light at first is better than too dark, as it will darken with the rest of the floor over time.

Gaps are the most debated point in any period floor. Narrow gaps are part of the character and will take up a bit as the season changes. Wide gaps between boards let cold air up from the void below, so if the room sits over a ventilated space, it is worth filling. Traditionally this was done with slivers of pine glued to the side of a board, or with rope dipped in linseed oil pushed into the gap. Modern flexible fillers move with the boards and are far quicker, but they can crack on a floor that moves significantly.

Sanding properly, without ruining the boards

Hire a drum sander for the main field of the floor and an edge sander for the borders. A drum sander removes material quickly, so keep it moving and work in overlapping passes at roughly 45 degrees to the grain, then finish along the grain. Start with a coarser grit only if the surface is truly rough, then step through the grades — typically 60, 80, 100 and 120. Going finer than 120 on old pine can burnish the surface and prevent a finish from soaking in.

Take care at the edges. The edges and corners are where a heavy machine cannot reach, and it is easy to leave a dished hollow in the middle of a board while chasing a stubborn mark. Hand sanding with a cork block in the corners is slower but far safer. Punch every nail below the surface before you begin, and be prepared for sparks if you miss one.

Sealing and finishing

Always test your chosen finish on an offcut or a hidden corner first, because pine yellows and deepens with age and some finishes darken it further.

• Hardwax oil: the most forgiving choice in a busy cottage. It soaks in, leaves a natural matt sheen, and can be spot-repaired without sanding the whole floor.
• Danish or boiled linseed oil: traditional and beautifully warm, but needs more frequent topping up.
• Water-based matt lacquer: hardwearing and quick-drying, though the first coat raises the grain and needs a light de-nibbing between coats.
• Wax: only on top of a sealed floor, never on bare boards, where it will sit in the grain and attract dirt.

Two or three thin coats, applied in a warm, well-ventilated room with the heating off, will always beat one thick one. Allow full drying time between coats.

Living with a period floor

Once sealed, the floor still needs a little care. Fit felt pads to every chair and table leg, lift rather than drag furniture, and keep the room's humidity reasonably stable — a floor that dries and swells dramatically will show every gap. Sweep regularly, clean with a pH-neutral product and a barely damp mop, and plan to re-oil high-traffic areas once a year or so.

In a small cottage or mews room, a bare board floor will actually make the space feel larger than a busy carpet does, particularly if you keep the finish light and let rugs do the softening. Choose one good wool rug rather than several small ones, and the boards will read as a deliberate feature rather than an unfinished job.