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Heritage Specialist
4.3/5 from 27+ reviews

Timber / Wood Frames

Replacement sealed units for timber and wood window frames. Timber reglazing requires careful measurement — accounting for paint buildup, putty lines, and wood movement. We manufacture sealed units from 14mm upward for traditional putty glazing and modern timber bead systems. Exact-size precision for period properties and contemporary timber frames alike.
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4.3/5 rating from 27+ reviews
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Hardwood, softwood, engineered timber — sash windows, casements, and French doors. Here's how to specify replacement sealed units for every timber frame type.

Expert Glazing, Done Right

We're not a national call centre. We're local glaziers who take pride in every job.

Account for Paint Buildup

Timber frames accumulate paint layers over decades — sometimes 3-5mm of paint narrows the rebate. Always measure the actual rebate depth at the deepest point, not the painted surface. Scrape a small area if needed to get a true measurement.

Putty or Bead Glazing

Traditional timber uses linseed putty on the exterior face. Modern timber uses screw-fixed or pinned timber beads. The glazing method determines edge clearance and whether you need a stepped unit or flat-face unit.

Moisture Management

Timber frames absorb and release moisture. Ensure drainage channels are clear and the back putty / glazing tape creates a good seal. Trapped moisture between the unit and timber accelerates both wood rot and seal failure.

5-7 Day Turnaround

Timber reglazing units are typically bespoke sizes — especially sash windows and period casements. Standard turnaround 5-7 working days.

10-Year Warranty

Every unit warranted for 10 years. For timber frames, we recommend annual inspection of the putty/seal line to ensure continued protection.

Timber reglazing has more variables than uPVC or aluminium. These checks prevent costly mistakes.

Signs Your Double Glazing Needs Attention

Catching problems early saves money and prevents bigger issues. Here are the telltale signs your windows need professional attention.

⚠️ Noticed any of these issues? Do not wait - small problems become expensive repairs. Get a free assessment today.

Expert Knowledge

Timber Reglazing: The Complete Trade Guide

Timber Frame Categories

Timber windows fall into three main reglazing categories:

Traditional Sash Windows — Sliding sashes with putty glazing. Typically require 14-20mm units to maintain sash balance and clearance. The sash must slide freely in the box frame with the new (potentially heavier) unit installed. Consider the counterbalance system: weights (traditional) or spiral balances (modern retrofit).

Timber Casements — Side-hung or top-hung casement windows. Accept a wider range of unit thicknesses (typically 20-28mm). Glazed with either putty or timber beads depending on age and style.

Contemporary Timber — Modern engineered timber windows from Scandinavian-style manufacturers (Rationel, NorDan, Velfac, etc.). Deep rebates, bead-glazed, accept standard unit thicknesses. Reglaze like uPVC but with tighter moisture management.

Putty Glazing Method

Traditional putty glazing uses linseed oil putty on the exterior face (weather putty) and a bed of putty or glazing compound on the interior face (back putty). The back putty creates a cushion and moisture barrier between the unit and the timber.

Critical: The putty line must slope away from the glass to shed water. Flat or reverse-sloped putty traps water against the seal edge and accelerates failure. Shape the putty to match a ~30 degree slope from the edge of the glass to the face of the timber.

Conservation Glazing

For Listed Buildings and Conservation Areas, the replacement glass may need to match the visual appearance of the original glazing. Options include:

Slim vacuum glazing — 6-8mm overall thickness that looks like single glazing from outside but provides double glazing thermal performance. Fits original putty rebates without modification.

Slim sealed units (14-16mm) — Thin enough to maintain traditional sash profiles. Low-E coating adds thermal performance invisibly.

Heritage glass types — Restoration glass with subtle surface texture that replicates the slight waviness of period glass. Available as the outer pane of a sealed unit for visual authenticity.

When upgrading sash windows from single to double glazing, the unit weight approximately doubles. If the sash uses traditional lead counterweights, they'll need adjusting — otherwise the sash will be too heavy to hold open. Calculate the new glass weight (glass density × area × thickness × 2 panes) and compare to the existing weight. Spiral balances are easier to adjust than lead weights.

Precision measurement with timber-specific considerations. We guide you through the specification.

How Our Service Works

From first contact to finished job, we make the whole process straightforward and stress-free.

Survey the Frame

Measure rebate dimensions (scrape paint if needed), check for rot, assess drainage, determine glazing method (putty or bead). For sash windows, note the balance type and measure sash thickness.

Specify the Unit

Tell us the frame type, rebate depth, and any conservation requirements. We'll recommend thickness, pane configuration, and whether standard or heritage glass is appropriate.

Order

Via trade portal, email, or phone. Timber orders are confirmed with a specification sheet before manufacture. Trade accounts get 30-day terms.

Fit with Care

Units dispatched within 5-7 working days. Allow time for proper putty application or bead fitting. Back-putty thoroughly and ensure the weather putty slopes correctly. A clean timber reglaze is a craft skill — it shows.
From slim heritage units to modern high-performance specifications — every configuration for timber reglazing.

What We Can Help With

From quick repairs to complete replacements, we handle all residential and commercial glazing needs.

Slim Sash Units (14-20mm)

For sliding sash windows and heritage casements. Maintains sash balance and traditional proportions. Low-E coating available at all thicknesses.

Low-E + Argon (24-28mm)

Standard energy upgrade for timber casements with adequate rebate depth. U-values from 1.1 W/m²K. The most popular timber upgrade specification.

Heritage Restoration Glass

Outer pane with subtle surface texture replicating period glass. Paired with a modern inner pane and insulating cavity. Visual authenticity with thermal performance.

Conservation Slim Units

Ultra-slim configurations (14-16mm) for Listed Buildings where standard double glazing would be visually inappropriate. Every millimetre matters.

Acoustic for Timber

Acoustic laminated configurations in slim and standard profiles. Period properties near busy roads benefit from both noise reduction and thermal upgrade.

Safety Glass

Toughened or laminated for doors, low-level panels, and overhead glazing in timber frames. All thicknesses and heritage configurations available.

Not sure what you need? No problem - we will assess and advise. No obligation, no pressure.

Trusted by Tradespeople & Homeowners

What Our Customers Say

4.3 ★ from 27 Google reviews

  • 15+

    Years in Business

  • 10,000+

    Sealed Units Supplied

  • 27+

    Google reviews

  • ★★★★★
    Huge shout-out to Ollie and the team! ⭐⭐⭐⭐⭐ ​Our patio door went from being completely stuck and impossible to lock to sliding like a dream. Ollie diagnosed the issue (collapsed wheels) and his team squeezed us in despite a packed schedule. ​The difference is night and day—it literally feels like it’s sliding on air now. If you’re looking for reliable, expert servi...

    Susan Passmore

  • ★★★★★
    We had glass panes and hinges replaced throughout the house and a new set of french doors. Ollie and everyone that came to fit were friendly, professional, tidy and considerate. The work has been carried out to excellent quality - especially the french doors which look fantastic.

    Lucy Bennett

  • ★★★★
    Complex issue with a broken non-standard hinge on 1st floor window. Ollie was the only one of over 10 other firms I contacted who said they could do the job. It took a while, but Ollie managed to source a replacement part and completed the job to a high standard. Very happy with the work done and have asked him to do another job following the good experience.

    Dave Edwards

Common questions about replacing sealed units in timber window frames.

Frequently Asked Questions

Everything you need to know about our double glazing repair and replacement services across the South West.

  • Often, yes — but it depends on the rebate depth and sash construction. If the rebate can accommodate a 14mm+ sealed unit with proper back putty clearance, double glazing is feasible. For sash windows, you'll also need to adjust the counterbalance. We recommend a site survey first.

  • If the property is Listed, you'll typically need consent for any change to the glazing. Slim sealed units (14-16mm) with heritage restoration glass are the most likely to be approved — they maintain the visual character while adding thermal performance. Always consult the conservation officer before ordering.

  • Scrape paint from the rebate at each measurement point to find the true timber dimension. Allow extra clearance (4mm per side instead of 3mm) if the paint is thick and uneven. Don't try to force a unit into a paint-narrowed rebate — it will crack when the timber swells.

  • Linseed putty for traditional timber windows — it allows moisture movement and is historically appropriate. Never use silicone on timber frames — it traps moisture, prevents the timber from breathing, and accelerates rot. For modern timber bead systems, use the manufacturer's recommended glazing tape.

  • 3mm per side minimum (6mm total) for timber frames. In exposed locations or with softwood frames that swell significantly, allow 4mm per side (8mm total). Timber moves more than uPVC or aluminium — generous clearance prevents stress cracking.

  • Yes. Timber conservatory reglazing is a specialist job — we manufacture roof and wall units in the correct configurations including self-cleaning outer glass and solar control options. Provide frame dimensions and we'll confirm specifications.

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Order Timber Replacement Units

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