Sash Window Repair & Restoration

Sash cords are the most common cause of sash window problems. Traditional waxed cotton cords connect the sash to the counterbalance weights hidden inside the box casing. Over time — typically 20 to 40 years — cords fray and eventually snap, causing the sash to drop and sit unevenly, or making it impossible to hold the window open without a prop.

We access the weights by carefully removing the staff bead, parting bead and pocket cover. Cords are replaced with quality waxed cotton or, for double-glazed units (which are heavier than single-pane glass), with sash chain or heavier-gauge cord. Weights are adjusted or replaced where necessary. The window is then re-hung, balanced and tested before we leave.

Sash cords are the most common cause of sash window problems. Traditional waxed cotton cords connect the sash to the counterbalance weights hidden inside the box casing. Over time — typically 20 to 40 years — cords fray and eventually snap, causing the sash to drop and sit unevenly, or making it impossible to hold the window open without a prop.

We access the weights by carefully removing the staff bead, parting bead and pocket cover. Cords are replaced with quality waxed cotton or, for double-glazed units (which are heavier than single-pane glass), with sash chain or heavier-gauge cord. Weights are adjusted or replaced where necessary. The window is then re-hung, balanced and tested before we leave.

Rot in sash window timber is almost always localised — most commonly at the base rail of the lower sash, the sill and occasionally the bottom of the pulley stile. In the majority of cases, rot can be repaired by cutting out the affected section and splicing in new Accoya or hardwood timber, bonded with Sikkens two-part adhesive and shaped to match the original profile.

For minor decay, we use a consolidant and filler system to stabilise and restore the timber without cutting. We only recommend full sash window replacement when more than 40 per cent of the structural timber is lost to rot or when the cased box frame itself has failed.

Rot in sash window timber is almost always localised — most commonly at the base rail of the lower sash, the sill and occasionally the bottom of the pulley stile. In the majority of cases, rot can be repaired by cutting out the affected section and splicing in new Accoya or hardwood timber, bonded with Sikkens two-part adhesive and shaped to match the original profile.

For minor decay, we use a consolidant and filler system to stabilise and restore the timber without cutting. We only recommend full sash window replacement when more than 40 per cent of the structural timber is lost to rot or when the cased box frame itself has failed.

A well-executed draught-proofing treatment transforms the performance of single-glazed sash windows. We fit pile weather seals to the sash edges and a brush seal to the meeting rail — eliminating the gaps that allow cold air in and warm air out without restricting the movement of the window.

The improvement in comfort is immediate and significant. Independent testing has shown that draughtproofed sash windows reduce heat loss through the frame by up to 86 per cent compared with unstripped windows. Paired with a double glazing upgrade, the performance improvement is comparable to a modern double-glazed unit.

A well-executed draught-proofing treatment transforms the performance of single-glazed sash windows. We fit pile weather seals to the sash edges and a brush seal to the meeting rail — eliminating the gaps that allow cold air in and warm air out without restricting the movement of the window.

The improvement in comfort is immediate and significant. Independent testing has shown that draughtproofed sash windows reduce heat loss through the frame by up to 86 per cent compared with unstripped windows. Paired with a double glazing upgrade, the performance improvement is comparable to a modern double-glazed unit.

Failed putty is both an aesthetic problem and a practical one: water ingress at the glass-to-frame junction is one of the primary causes of timber deterioration. We regraze where necessary, using linseed oil putty for traditional windows or modern gun-grade glazing compound where appropriate. Cracked or broken panes are replaced with matching glass — horticultural, obscure or standard clear.

Failed putty is both an aesthetic problem and a practical one: water ingress at the glass-to-frame junction is one of the primary causes of timber deterioration. We regraze where necessary, using linseed oil putty for traditional windows or modern gun-grade glazing compound where appropriate. Cracked or broken panes are replaced with matching glass — horticultural, obscure or standard clear.

Original sash hardware — lifts, fasteners and pulleys — is often worn or missing. We can replace like-for-like with period-style cast brass or polished chrome hardware, or upgrade to a modern locking fastener where security is a concern. All pulleys are checked and replaced as needed during cord replacement.

Original sash hardware — lifts, fasteners and pulleys — is often worn or missing. We can replace like-for-like with period-style cast brass or polished chrome hardware, or upgrade to a modern locking fastener where security is a concern. All pulleys are checked and replaced as needed during cord replacement.