Restore or replace your sash windows?

Why restoring usually comes first

A window made a hundred years ago was cut from slow grown timber that is denser and more durable than most timber sold today. Where the wood is sound, keeping it is usually the better long term choice, and a restored window can always be repaired again. It is also the route every conservation authority prefers: Historic Environment Scotland's guidance puts repair first, and in a listed building like for like repair generally needs no consent at all.

Signs your windows can be restored

• Draughts and rattles. Worn beads and unsealed gaps, cured by adjusting the beads and fitting draught proofing.
• Stuck or painted shut. Layers of paint and swollen timber; the sashes are eased, stripped and rebalanced.
• A sash that crashes down or will not stay open. Almost always broken cords: new cords and rebalanced weights.
• Soft wood on the sill or the bottom rail. Decay is cut out and new timber spliced in, so the rest of the window is kept.
• Cracked glass or loose putty. Reglazed like for like and repainted.

None of these on its own means a window needs replacing. See what a restoration includes.

When you want double glazing but not new windows

If the case in the wall is sound but you want the warmth and quiet of double glazing, there is a middle route: keep the original case and fit new slim double glazed sashes made to match its sections and sight lines. From the street it looks unchanged. In a listed building this needs consent, but it is one of the options Edinburgh's guidance lists before full replacement. See double glazing upgrades and our listed building guide.

When replacement is the right call

• Decay runs through most of the sash or the case, not just a sill or a rail.
• An earlier replacement (often uPVC or a poor copy) has already lost the original, and you want the character back.
• You want new windows throughout and the building's status allows it.

In a listed building, councils expect evidence that windows are beyond practicable repair before they approve replacement. When a new window is needed, we make it in our own Glasgow workshop to the pattern of the original. See new sash and case windows.