Why old joinery deserves a second chance

In a stone cottage or a timber-framed farmhouse, the doors and windows are often the best-made things in the building. The timber was slow-grown, the joints are mortise and tenon, and the wood has settled into the frame over a century or more. Ripping them out for plastic replacements is almost always a mistake: you lose the proportions that make the house look like itself, and you trade a repairable window for one with a twenty-year lifespan and a landfill problem.

The draughts, though, are real. Old joinery was built with a small gap as part of the design, because timber swells and shrinks with the seasons. Those clearances are what let cold air whistle past on a February evening. The good news is that almost all of that heat loss can be stopped with brushes, seals and a decent pair of curtains, for a fraction of the cost of replacement, and with nothing that cannot be undone later.

Find the draughts before you buy anything

Wait for a windy day, then work round the house with the back of your hand. Your skin is more sensitive to moving air than you think. A lit incense stick or a candle held near a suspected gap shows the draught as a flicker of smoke or flame, which is useful in a dim hallway where your hand can't feel much.

Check these spots in particular:

• The base of external doors, especially where a threshold has been replaced or a floor level has changed.
• The meeting rail of sash windows, where the top and bottom sashes overlap.
• Around the whole perimeter of a casement window, particularly the hinge side and the handle side.
• Letterboxes, keyholes and the gap behind skirting where an old floorboard has lifted.
• Where a door frame has moved away from a stone or brick reveal, often hidden behind the architrave.

Note what you find on a sketch of each opening. It sounds fussy, but you will save yourself three trips to the ironmonger.

Brush, wiper and bubble seals

Most draught-proofing for old joinery comes down to three products. Brush pile seals, sold on a carrier strip or as a self-adhesive strip, are the workhorse for doors and sliding parts. Wiper seals, a flexible rubber fin on a rigid spine, work well on casements that open and close against a stop bead. Bubble or P-profile seals compress into a gap and suit frames with a consistent clearance of two or three millimetres.

A few rules make the difference between a job that lasts and one that jams:

• Clean the surface with white spirit and let it dry. Adhesive fails on dusty, waxy or damp timber.
• Leave the joinery a millimetre of clearance. If you have to force the door, the seal will wear out in a season and the hinges will suffer.
• Never fit a seal where it will sit in a painted rebate that gets repainted every few years. Brushes clog and stop working.
• Screw-fix carrier seals are worth the extra effort on external doors. Adhesive versions let go in cold, damp conditions.
• Treat bare timber with linseed oil or a breathable finish before fitting, so any trapped moisture can still escape.

For a solid timber door, a screw-on brush strip along the bottom is quick and effective. If the threshold is uneven, a hinged flap seal or a threshold plate with a rubber gasket does a better job. Add a brush-lined letterbox cover and a keyhole escutcheon while you are there; together they cost very little and stop a surprising amount of cold air.

Sash windows: three gaps worth tackling

Sashes are lovely and notoriously leaky. Work on the three places where air actually moves.

The meeting rail. Where the sashes overlap, cut a rebate seal or fit a slim bubble seal to the inner face of the top rail. Some sashes were made with a shallow groove here, which takes a brush seal neatly.

The staff beads. These are the vertical beads holding the lower sash in place. A brush seal in the groove, or a wiper seal pinned to the bead, stops draughts up the sides without interfering with the sash's travel. Do the same on the parting beads between the sashes.

The outer frame. Run a brush seal around the staff bead where it meets the reveal, and check the sill. A worn sill or a missing drip can let water in as well as air, so deal with that before sealing anything.

If the sashes rattle, that is usually worn cords or a loose bead rather than a draught problem, and it is worth having them overhauled properly. Well-maintained sashes with good seals can outperform many modern units.

Curtains, shutters and secondary glazing

Seals deal with gaps. Curtains deal with the cold surface of the glass itself, which is where a lot of the heat actually leaves the room.

A heavy interlined curtain, hung from a track fixed close to the ceiling and wide enough to overlap the window reveal by 150mm on each side, is remarkably effective. Add a pelmet or a simple fabric valance to stop warm air rolling down behind the curtain, and make sure the curtains close fully at night. Thermal linings help, but weight and a proper fit help more.

Where you want something less soft, timber shutters or a removable secondary glazing panel made from acrylic or glass in a slim frame will cut draughts and condensation noticeably. Both are reversible, which matters in a listed building or a conservation area. If your property is listed, check with the conservation officer before fixing anything permanent to the joinery, though most draught-proofing falls within normal maintenance.

A seasonal check that pays for itself

Draught-proofing is not a one-off job. Test your seals each autumn, before the cold settles in, and replace any brush strips that have flattened or stiffened. Warm, still air inside a house is a sign the work is holding; a persistent chill near a window or door means there is a gap you have missed.

Spend an afternoon on it, and you will feel the difference the same evening. Your old joinery stays exactly where it belongs, and the house gets warmer without losing a scrap of its character.