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Timber & Wooden Windows — London

Timber Window Repair London

Wooden Window Restoration Specialists

We repair and restore timber windows of all types across London — sash, casement, bay, and period frames. From rot repairs and draught proofing to double glazing upgrades, our master joiners keep your original wooden windows performing as they should.

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FENSA Registered Certified Installers

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Accoya® Approved 50-Year Anti-Rot Warranty

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All London Boroughs Conservation Areas Welcome

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5-Star Rated 150+ Google Reviews

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Timber Window Repair & Wooden Window Restoration in London

London's period housing stock is built almost entirely with original timber windows — and most of them are still repairable. Whether you have box sash windows, casement windows, or any other wooden frame, repair and restoration is nearly always more cost-effective than replacement, better for the building, and the only appropriate option in a conservation area or listed property.

Types of Timber Windows We Repair

Box Sash Windows

The most common timber window type in Victorian and Edwardian London. Upper and lower sashes slide vertically on cords, weights, and pulleys concealed within the frame box. We carry out the full range of sash window repairs — cords, pulleys, beads, putty, rot, draughts, and double glazing upgrades.

Casement Windows

Side-hung timber casements are common in Edwardian, Arts and Crafts, and inter-war properties. We repair broken hinges, swollen frames, failed glazing, rot in the bottom rail, and draught seal deterioration. Draught proofing a casement window can cut heat loss dramatically without any visible change.

Bay Windows

Bay windows in period properties typically combine sash windows set within a projecting timber structure. The bay frame itself is as vulnerable to rot and movement as the individual windows. We repair the sashes and assess the structural condition of the bay surround as part of the same visit.

Period & Listed Timber Frames

Georgian and early Victorian timber windows often have thinner glazing bars, ovolo mouldings, and decorative horns that are irreplaceable if the frame is lost. We specialise in sympathetic repair of period frames using matching timber profiles and traditional joinery techniques that meet conservation area and listed building requirements.

Common Timber Window Faults & How We Fix Them

Rot in the timber frame or sill

The most common reason for timber window failure. Wet rot starts where water can pool — typically the bottom rail of the lower sash, corner joints, and the sill. In the majority of cases the rot can be cut back and repaired using high-strength epoxy consolidant and filler rather than replacing the whole frame. Where rot is too extensive, we splice in new matching timber. Full frame replacement is rarely necessary.

Draughts and heat loss

Uncontrolled air infiltration through the gaps in a timber window is one of the largest sources of heat loss in a period property. We fit brush pile draught seals into routed channels in the frame — invisible when the window is closed, effective for 20+ years, and compatible with both single and double glazed units. A single draught-proofed sash window can reduce heat loss through that opening by 40–50%.

Sticking, swelling, or difficult operation

Timber expands and contracts with moisture and temperature. Windows that are difficult to open in summer, or that have been painted shut, are a very common complaint. We identify whether the cause is timber movement, failed cords (on sash windows), accumulated paint layers, or settlement in the frame, and carry out the appropriate repair.

Failed or cracked glazing

Whether you have single glazing with failed putty, or a misted double glazed unit with a broken seal, we replace the glass unit within the existing timber frame. We can upgrade single glazed timber windows to slimline double glazed units (as thin as 14mm) that fit the original rebate without altering the frame.

Paint failure and surface deterioration

Flaking, cracked, or missing paintwork is what allows moisture into the timber. Once the paint breaks down, rot follows quickly. As part of any timber window repair we address the surface condition — stripping back failed layers, priming bare timber, and applying a finish coat. Properly maintained paintwork is what makes a timber window last.

Noise and acoustic performance

Timber windows with gaps around the frame transmit road and neighbour noise directly into the room. Draught proofing alone significantly reduces this. Upgrading to laminated or acoustic double glazed units provides a further reduction. Both can be carried out without replacing the timber frame.

Should You Repair or Replace Your Timber Windows?

The vast majority of timber windows — even ones that look badly deteriorated — are repairable. Original timber from the Victorian and Edwardian era is often old-growth hardwood that is denser and more durable than anything available today. Rot, if caught before it reaches the structural joints, can be repaired with epoxy. Draughts, glazing failures, and paint problems are all straightforward repairs.

Full replacement only makes sense when the structural joints have completely failed, when the frame has twisted beyond repair, or when the window is a non-original replacement that holds no historic value.

We will always give you an honest assessment. If repair is the right answer — and it usually is — we will tell you. If the frame genuinely cannot be saved, we will tell you that too, and we can replace it with a timber window made to the original specification using Accoya® — the only timber with a 50-year anti-rot guarantee.

Timber We Use for Repairs & Replacements

When new timber is needed — for splicing in, sill replacement, or full frame manufacture — the species matters.

Softwood (Redwood / Pine)

The most affordable option and suitable for repairs where the section being replaced is small. Must be kept well painted to remain durable. Matches most existing Victorian and Edwardian frames.

From £150

Hardwood (Idigbo / Sapele)

Significantly more durable than softwood and naturally more resistant to rot. A better choice for exposed locations or areas with a history of moisture problems. Slightly higher cost, substantially longer lifespan.

From £250

Our Preferred Choice

Accoya® (Modified Timber)

The only timber with a 50-year above-ground anti-rot guarantee. Dimensionally stable (does not swell in damp), accepts paint exceptionally well, and is the benchmark material for conservation and heritage work. We are Approved Accoya Contractors.

From £350

Timber Window Repair Costs in London

Costs vary depending on the extent of the damage, the number of windows, and the timber species chosen. These figures give a general guide:

Draught Proofing

From £200

Per sash or casement window

Rot Repair

From £150

Epoxy consolidation & fill

Glass Replacement

From £200

Slimline DGU retrofit

Full Restoration

From £400

Per window, all works

All prices are per window and exclude VAT. A free site survey is required for an accurate quote — call 020 3488 1695 to arrange.

Frequently Asked Questions

Is it worth repairing old timber windows or should I replace them?

In the majority of cases, repair is the better option. Original Victorian and Edwardian timber is often old-growth wood that is denser and more durable than modern equivalents. With proper repair and maintenance, original timber windows can last indefinitely. Replacement windows — even timber ones — need regular repainting and can take 20 years before their embodied carbon is offset by energy savings. We'll always advise honestly based on the condition of your specific windows.

Can you repair timber windows in a conservation area?

Yes — repair is nearly always permitted without planning consent in conservation areas. What you cannot do without consent is replace the windows with a different material or style. We specialise in conservation area work and are familiar with the requirements of London councils including Islington, Camden, Hackney, Haringey, and Lambeth. We can advise on whether your planned works require consent and what the council's design guidance requires.

Can wooden windows be made more energy efficient without replacing them?

Yes, significantly. Draught proofing alone can reduce heat loss through a timber window by 40–50% and is effective, invisible, and durable. Upgrading from single glazing to slimline double glazed units within the existing frame adds further thermal and acoustic improvement. The combination of draught proofing and double glazing brings a timber sash or casement window to near-modern thermal performance levels without any change to its appearance from the outside.

How do you repair rot in a wooden window without replacing the whole frame?

We cut back the rotten timber to sound wood, treat the area with epoxy consolidant to harden any remaining soft fibres, and build back the profile using two-part epoxy filler. Once cured, this repair is harder than the surrounding timber and will not rot again. For more extensive damage we splice in new timber sections, carefully matched for profile and species, using traditional mortice and tenon joinery. The result is indistinguishable from the original.

Do you repair casement windows as well as sash windows?

Yes — we repair all types of timber windows including casement, sash, bay, and any other wooden frame. Casement repairs typically involve hinge replacement, frame re-squaring, draught proofing, glazing bead and putty work, and rot repairs to the bottom rail and sill. The work is straightforward and usually completed in a single day per window.

What is Accoya and why do you recommend it?

Accoya is a sustainably sourced softwood that has been modified through an acetylation process, making it dimensionally stable (it barely swells or shrinks with moisture), extremely hard, and guaranteed not to rot above ground for 50 years. It outperforms hardwood for paint adhesion and durability. We are Approved Accoya Contractors — one of a small number of specialist firms in London authorised to work with it. When new timber is required, Accoya is our first recommendation.

Ready to repair your timber windows?

Free site survey across London. We assess every window and give you an honest recommendation before any work begins.

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Related Services

Sash Window Repair London

Specialist repair of box sash windows — cords, pulleys, beads, weights, and draught seals.

Sash Window Restoration

Full sash window restoration — stripping, repairing, draught proofing, glazing, and repainting.

Draught Proofing

Brush pile seals fitted to eliminate draughts, reduce heat loss, and cut noise.

Double Glazed Sash Windows

Slimline double glazed units retrofitted into original timber frames across London.

Window Sill Replacement

Rotten or damaged timber sill replacement using softwood, hardwood, or Accoya.

Period Property Window Repairs

Conservation area and listed building window repairs, carried out to heritage standards.

Why Choose Us

London's Timber Window Specialists

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Comprehensive Service

Here at Golden Ratio Windows we have built up an excellent reputation in our local area by offering the most comprehensive and expert timber window repair service in London. From the planning stage to the finished article; we are with you every step of the way.

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Professional & Personal

With so many years working in the trade, we are happy to answer any queries and provide quotes for any work. Rest assured that you will be receiving a professional, yet personal service across all of London and the surrounding areas.

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