In this article, you’ll discover:

• The main arch styles and their architectural origins
• How curved timber windows are actually manufactured
• Realistic lead times and cost premiums for arched windows
• Which properties suit arched window designs
• Key specification considerations for curved glazing

Introduction

Arched windows make statements. Whether it’s a Gothic pointed arch in a church conversion, a Romanesque curve in a Victorian villa, or a subtle segmental arch adding character to a cottage, curved windows create architectural interest that rectangular openings simply can’t match.

But arched windows are genuinely challenging to manufacture well. The curves demand different construction techniques, specialist skills, and longer production times. That translates to higher costs and longer lead times — typically 40-60% more expensive than equivalent square-headed windows, with 10-14 week delivery rather than 6-8 weeks.

We manufacture bespoke timber windows including arched designs for properties across the UK. This guide explains what’s involved: the different arch types, how they’re made, what they cost, and whether they’re right for your project.

Arch Types: Gothic, Romanesque and Segmental

Different arch shapes suit different architectural contexts. Understanding the options helps you specify appropriately.

Gothic Arches (Pointed)

Gothic arches come to a point at the apex, created by two arcs meeting at an angle. They’re the defining feature of medieval ecclesiastical architecture and remain common in church conversions, Victorian Gothic revival buildings, and properties with religious origins.

The pointed profile creates a distinctive vertical emphasis. Gothic arches suit:

• Church and chapel conversions
• Victorian Gothic revival properties
• Buildings with existing Gothic architectural features
• Statement feature windows where drama is intended

Gothic arches are the most complex to manufacture due to the compound curves meeting at the apex.

Romanesque Arches (Semi-circular)

Romanesque arches form a perfect semicircle — the simplest curved form geometrically. They predate Gothic architecture and remain common in Norman buildings, Georgian architecture, and classical revival styles.

The rounded profile creates a softer, more classical appearance. Romanesque arches suit:

• Georgian and Regency properties
• Classical revival buildings
• Norman or Romanesque historic structures
• Situations requiring elegant simplicity

Semi-circular arches are easier to manufacture than Gothic pointed arches because the curve is uniform throughout.

Segmental Arches (Shallow Curve)

Segmental arches are shallow curves — less than a semicircle. They’re the most common arch type in domestic British architecture, appearing on countless Victorian and Edwardian properties where a subtle curve adds character without dramatic statement.

The shallow profile creates gentle visual interest without dominating. Segmental arches suit:

• Victorian terraces and semis
• Edwardian properties
• Cottages and traditional homes
• Any property where subtle detailing is preferred

Segmental arches are the most straightforward curved windows to manufacture.

Comparison Table

Manufacturing Curved Timber Windows

Arched windows require fundamentally different construction approaches than rectangular windows.

Laminated Curved Sections

The standard method for curved timber frames uses lamination. Thin strips of timber are glued together over a curved former, creating a solid curved section once the adhesive cures.

Laminated construction offers several advantages:

• Strength: Laminated curves are stronger than solid timber bent to shape
• Stability: The alternating grain directions resist warping
• Precision: Accurate curves can be achieved consistently
• Any radius: Both tight curves and gentle arcs are possible

The process requires accurate formers (expensive for one-offs) and extended production time for adhesive curing. This explains much of the cost premium.

Solid Timber Curves

For gentle curves like segmental arches, solid timber can sometimes be used. The curve is cut from a larger section of timber, with grain running as close to parallel with the curve as possible.

This works for shallow curves but becomes impractical for tighter radii — too much cross-grain weakness and too much waste.

Glazing Considerations

Curved openings present glazing challenges:

Curved glass is possible but expensive. True curved glass (bent while hot) costs significantly more than flat glass and requires specialist suppliers. Most curved windows use flat glass in curved frames.

Faceted glazing approximates curves using multiple small flat panes. This works well for Romanesque and Gothic designs where traditional glazing patterns would have used small panes anyway.

Single curved pane with flat glass sits in the curved frame with a slight gap at the curve extremes. Acceptable for gentle segmental arches but noticeable on tighter curves.

Lead Times and Costs

Arched windows require longer production schedules and command premium pricing.

Typical Lead Times

• Standard rectangular windows: 6-8 weeks
• Segmental arch windows: 10-12 weeks
• Gothic and Romanesque arches: 12-14 weeks
• Complex bespoke curved designs: 14-16+ weeks

The extended timeline reflects former creation, lamination curing time, and the additional handwork required for curved sections.

Cost Premiums

Expect arched windows to cost 40-60% more than equivalent square-headed windows. For complex Gothic designs or very tight curves, premiums can reach 80-100%.

A segmental arch casement that might cost £600 as a rectangular window typically costs £840-£960 as an arched version. A large Gothic arch feature window can easily exceed £2,000-£3,000.

Factors Affecting Arched Window Costs

• Curve complexity: Gothic more than Romanesque more than segmental
• Size: Larger arches require larger formers and more material
• Glazing pattern: Multiple panes add complexity
• Opening mechanism: Fixed lights cost less than opening sashes
• Timber species: Hardwood adds further premium

Applications: Where Arched Windows Work Best

Arched windows suit specific contexts. Using them inappropriately looks awkward regardless of manufacturing quality.

Church and Chapel Conversions

The obvious application. Gothic and Romanesque arches are architecturally authentic for religious buildings. Replacement windows should match original profiles exactly — planning authorities and conservation officers expect accuracy.

Victorian Gothic Revival Properties

Many Victorian buildings incorporated Gothic detailing — pointed arches, tracery patterns, ecclesiastical references. Arched windows complement this existing character.

Georgian Properties and Feature Windows

Romanesque (semicircular) arches suit Georgian architecture’s classical references — fanlights over doors, Venetian windows, and decorative arch-topped features. Beyond period accuracy, a single arched window can create a focal point at a staircase landing or illuminating a double-height space. Used sparingly, arches add character without overwhelming.

Period Property Restoration

Where original arched windows survive but need replacement, matching the existing profile maintains architectural integrity. Listed buildings and conservation areas typically require accurate reproduction.

Specification Considerations

Getting arched window specifications right prevents expensive mistakes.

Measuring Curved Openings

Accurate measurement is critical. Unlike rectangular openings where width and height suffice, curved openings need:

• Overall width at widest point
• Overall height from sill to apex
• Curve profile (radius for simple curves, or template for complex shapes)
• Spring point (where curve begins)

For complex arches, a cardboard template of the opening is often the safest approach. We can work from photographs and measurements, but templates eliminate ambiguity.

Glazing Bar Patterns

Arched windows historically featured glazing bars following the curve. Georgian-style patterns might include radial bars fanning from the centre, while Gothic designs often incorporated tracery.

Modern sealed glazing units make complex patterns expensive. Consider whether elaborate glazing bars are necessary or whether simpler patterns achieve similar effect.

Hardware and Operation

Arched-top windows are often fixed lights with rectangular opening sections below. This simplifies hardware — curved opening sashes require specialist hinges and stays.

Where opening arched sashes are essential, budget additional time and cost for bespoke hardware solutions.

Frequently Asked Questions

How much more do arched windows cost than rectangular?

Expect 40-60% premium for most arched designs. Simple segmental arches sit at the lower end; complex Gothic designs reach 80-100% premium. A rectangular casement costing £600 might cost £840-£960 as a segmental arch, or £1,080-£1,200 as a Gothic arch. These premiums reflect manufacturing complexity, not profit margins.

Can any window company make arched windows?

No. Curved window manufacture requires specialist equipment, skills and experience. Many window companies decline arched work or subcontract it. Ask specifically about arched window experience, request examples of previous curved work, and expect longer lead times. Manufacturers who regularly produce curved windows achieve better results than those attempting occasional one-offs.

What’s the lead time for arched timber windows?

Typically 10-14 weeks compared to 6-8 weeks for rectangular windows. Complex Gothic designs or bespoke curves may extend to 14-16 weeks. The additional time covers former creation, lamination curing, and the extra handwork curved sections require. Plan your project timeline accordingly — arched windows shouldn’t be specified at the last minute.

Do arched windows need planning permission?

Same rules as any window replacement. Like-for-like replacement of existing arched windows is usually permitted development. Changes to arch profiles, or installing arched windows where rectangular existed, may require planning approval in conservation areas and always require Listed Building Consent for listed properties. Check with your local planning authority before committing.

Can arched windows be double or triple glazed?

Yes, though with some considerations. Curved sealed units are possible but expensive. Most arched windows use flat glass within curved frames — acceptable for gentle curves but noticeable on tight radii. For maximum thermal performance with arched designs, discuss glazing options during specification. Argon-filled double glazing works well in most arched configurations.

Conclusion

Arched timber windows add genuine architectural distinction to appropriate properties. Gothic arches suit ecclesiastical conversions and Victorian Gothic revival buildings. Romanesque semicircles complement Georgian and classical architecture. Segmental arches provide subtle character for Victorian terraces and cottages.

The premium pricing and extended lead times reflect real manufacturing complexity. Curved windows can’t be rushed without compromising quality. Budget appropriately, plan timelines realistically, and choose a manufacturer with genuine curved window experience.

At Timber Windows Direct, we manufacture bespoke arched windows in all configurations — Gothic, Romanesque, segmental and bespoke curves. Every window is made to order using laminated construction for strength and accuracy. Request your free quote and let’s discuss your arched window requirements.

In this article, you’ll discover:

• The key differences between sash, casement and bay timber windows
• Why engineered timber outperforms solid wood in most applications
• How timber compares to uPVC and aluminium on cost, performance and aesthetics
• Realistic price ranges for different timber window types
• Energy efficiency ratings and what U-values actually mean for your bills
• Maintenance requirements — and why they’re less demanding than you think

Introduction

Here’s a question we hear constantly: “Are timber windows worth the extra money?” The short answer is yes — but the full picture is more nuanced than most websites will tell you.

Timber windows have been the backbone of British architecture for centuries. From Georgian townhouses to Victorian terraces, Edwardian villas to modern eco-builds, wood-framed windows remain the gold standard for homeowners who think beyond the next five years.

But the timber window market has changed dramatically. Engineered timber has largely replaced solid wood. Factory-applied microporous finishes mean maintenance cycles of 8-12 years, not annual repainting. And thermal performance now rivals — often exceeds — synthetic alternatives.

We’ve spent over a decade manufacturing bespoke timber windows for UK homes. This guide distils that experience into practical advice: what to look for, what to avoid, and how to make a decision you won’t regret in twenty years.

Types of Timber Windows: Sash, Casement and Beyond

Choosing the right window style affects everything from ventilation to kerb appeal. Here’s what actually matters.

Sash Windows

The classic British choice. Sash windows feature two movable panels (sashes) that slide vertically past each other. They’re defined by their elegance, excellent ventilation control, and suitability for period properties.

Traditional sash windows use a weight-and-pulley system concealed in the frame. Modern versions often use spiral balances instead — less historically accurate but perfectly functional for new builds. For listed buildings and conservation areas, the traditional mechanism is typically required.

Sash windows suit: Georgian, Victorian and Edwardian properties, conservation areas, anyone prioritising authentic period aesthetics.

Casement Windows

The most versatile option. Casement windows are hinged at the side (or top) and open outward. They offer maximum ventilation, easy cleaning access, and work with virtually any architectural style.

Flush casement windows sit flush with the frame when closed — a cleaner look that suits both traditional cottages and contemporary designs. Standard casements overlap the frame slightly, creating a more pronounced shadow line.

Casement windows suit: Modern homes, cottages, farmhouses, and properties where maximum airflow matters.

Bay and Bow Windows

Bay windows project outward from the building, creating additional interior space and dramatic architectural interest. The three main types are:

Bay windows often require structural support and may need planning permission, particularly for new installations.

Tilt-and-Turn Windows

Popular in Europe, gaining ground in the UK. Tilt-and-turn windows tilt inward at the top for secure ventilation, or swing fully inward for cleaning and emergency egress. They’re excellent for upper floors where external access is difficult.

Timber Species: Softwood, Hardwood and Engineered Options

The wood you choose affects durability, appearance, maintenance requirements and cost. There’s no single “best” option — it depends on your priorities.

Engineered Softwood

Engineered softwood windows are now the industry standard, and for good reason. Multiple layers of timber are bonded together with grains running in alternating directions. The result is exceptional dimensional stability — meaning less warping, shrinking and swelling than solid timber.

Engineered pine (typically redwood) offers:

• Superior stability compared to solid wood
• Consistent quality with natural defects removed
• Excellent paint adhesion
• 30-40 year lifespan with proper maintenance
• The most cost-effective timber option

For most UK homeowners, engineered softwood represents the sweet spot between performance, longevity and value.

Hardwood Options

Hardwoods offer natural durability and distinctive grain patterns. The main species used for windows include:

Oak — The traditional British choice. Extremely durable (60+ year lifespan), develops a beautiful silver-grey patina if left untreated, or can be finished in any colour. Premium pricing: typically 50-70% more than softwood.

Meranti — A tropical hardwood offering excellent durability at a more accessible price point. Stable, machines well, and accepts finishes beautifully. Often called the “best value hardwood.”

Accoya — Modified softwood with hardwood-class durability. Sustainably produced, dimensionally stable. Premium pricing but exceptional longevity.

Comparison Table: Timber Species

Timber vs uPVC vs Aluminium: An Honest Comparison

Let’s cut through the marketing and look at what actually matters.

Upfront Cost

Yes, timber windows cost more initially. Expect to pay:

• uPVC: £300-£600 per window
• Timber: £500-£1,200 per window
• Aluminium: £600-£1,000 per window

That’s 40-100% more for timber compared to basic uPVC. But upfront cost tells only part of the story.

Lifespan and Total Cost of Ownership

Here’s where timber wins convincingly:

• uPVC lifespan: 20-25 years (then full replacement)
• Timber lifespan: 30-60+ years (with maintenance)
• Aluminium lifespan: 30-45 years

A quality timber window can last two to three times longer than uPVC. Factor in replacement costs, and timber often works out cheaper over the building’s lifetime.

Thermal Performance

Modern timber windows achieve U-values of 1.4 W/m²K with double glazing, and 1.0-1.2 W/m²K with triple glazing. That comfortably exceeds Building Regulations Part L requirements (1.4 W/m²K for replacements).

Timber is a natural insulator. Frame U-values for timber typically outperform both uPVC and aluminium — the frame itself doesn’t conduct heat the way synthetic materials do.

Environmental Impact

Timber is the only window material that’s genuinely renewable. Trees absorb CO2 as they grow; that carbon remains locked in the wood for the window’s lifetime. At end of life, timber can be recycled, composted, or used for biomass energy.

uPVC production involves chlorine chemistry and plasticisers. Aluminium requires enormous energy to produce (though it’s recyclable). For environmentally-conscious homeowners, timber is the clear choice.

Aesthetics

This is subjective, but there’s a reason timber windows command premium prices in conservation areas and period properties. Wood has warmth, texture and character that synthetic materials simply can’t replicate. uPVC manufacturers have tried woodgrain foils for decades — the results still look like plastic.

Timber Window Costs: What to Expect in 2026

Pricing varies enormously based on size, style, timber species and glazing specification. These ranges reflect typical UK prices for supply-only bespoke windows:

Price Ranges by Window Type

Factors Affecting Price

Several elements push costs up or down:

• Glazing: Triple glazing adds 15-25% vs double glazing
• Size: Larger windows cost more (obviously), but not proportionally — a window twice the size isn’t twice the price
• Hardware: Premium ironmongery (monkey tail handles, brass fittings) adds £20-£50 per window
• Finishing: Factory spray finishing is standard; specialist colours or stains may cost extra
• Glazing bars: Georgian or Victorian patterns with authentic putty-line glazing bars add complexity

Installation Costs

As a supply-only manufacturer, we don’t install — but expect installation costs of £150-£350 per window depending on access, scaffolding requirements, and your location.

Energy Efficiency and Building Regulations

Understanding energy performance helps you make informed decisions and ensures compliance with Building Regulations.

What U-Values Mean

U-value measures how quickly heat passes through a material. Lower is better. Building Regulations Part L requires replacement windows to achieve U-values of 1.4 W/m²K or better.

Quality timber windows easily exceed this:

• Double glazed timber: 1.4 W/m²K
• Triple glazed timber: 0.8-1.2 W/m²K

Glazing Options

Double glazing with low-E glass and argon fill is the current standard. It offers excellent performance for most UK applications.

Triple glazing makes sense for:

• North-facing elevations
• Exposed locations
• Passive house or ultra-low energy builds
• Noise reduction priority areas

Ventilation Requirements

Building Regulations require background ventilation in habitable rooms. Trickle vents — small openings in the window frame — satisfy this requirement without compromising security. They’re now standard on most new timber windows.

Maintenance: The Truth About Looking After Timber Windows

The maintenance myth has cost timber windows countless sales. Let’s set the record straight.

Modern Reality vs Old Assumptions

Your grandmother may have painted her windows annually. Modern timber windows are different:

• Factory-applied microporous finishes last 8-12 years
• Engineered timber resists warping and movement
• Quality weatherstripping maintains airtightness for decades

What Maintenance Actually Involves

Annually: Quick visual inspection. Check for paint chips or cracks, especially on south-facing windows. Clean frames with mild soapy water.

Every 8-12 years: Full redecoration. Sand lightly, apply fresh microporous paint system. A competent DIYer can do this; professional decorators charge £30-£50 per window.

As needed: Replace weatherstripping (easy, inexpensive), lubricate hardware, address any localised damage.

Compared to Alternatives

uPVC requires less routine maintenance — but when it fails (discolouration, warping, mechanism failure), replacement is the only option. Timber can be repaired, sanded, refinished and restored. A 100-year-old timber sash window can be made as good as new; a 25-year-old uPVC window goes to landfill.

Frequently Asked Questions

How long do timber windows last?

Lifespan depends heavily on timber species and maintenance. Engineered softwood windows typically last 30-40 years with proper care, meranti 40-50 years, and oak 60+ years. Well-maintained Victorian sash windows regularly exceed 120 years. The key factor isn’t the wood — it’s consistent maintenance. Never let bare timber remain exposed to weather, address paint breakdown promptly, and your windows will outlast you.

Are timber windows more expensive than uPVC?

Yes, typically 40-100% more upfront. However, timber windows last two to three times longer than uPVC, can be repaired rather than replaced, and add more value to properties. Estate agents report timber windows can increase valuations by 5-10%, particularly in conservation areas. Over a 60-year period, timber often proves cheaper than replacing uPVC windows twice.

Do timber windows meet Building Regulations?

Absolutely. Modern timber windows comfortably exceed Building Regulations Part L requirements. Quality double-glazed timber windows achieve U-values of 1.4 W/m²K (the requirement). Triple-glazed options reach 1.1 W/m²K or better. When professionally installed, timber windows qualify for FENSA certification just like any other material.

What’s the best timber species for windows?

It depends on your priorities. For maximum longevity and heritage properties, oak is the benchmark. For conservation areas where hardwood appearance matters but budget is realistic, meranti offers excellent value. For most modern homes prioritising cost-effectiveness, engineered softwood delivers superb performance. All species perform well in UK conditions when properly finished and maintained.

How often do timber windows need painting?

With modern factory-applied microporous finishes, expect 8-12 years between full redecorations. Lighter colours (white, cream) typically last longer than dark colours. South-facing windows weather faster than north-facing ones. Annual inspection catches any problems early — a touch-up to paint chips takes minutes and prevents bigger issues.

Can I get timber windows in a conservation area?

Timber windows are usually the preferred or required option in conservation areas. Planning authorities recognise that timber is the historically authentic material for most period properties. You’ll typically need planning approval for the design (glazing pattern, proportions, details), but the material itself is rarely an issue. In listed buildings, timber is almost always mandatory.

Are timber windows energy efficient?

Very. Timber is a natural insulator with inherently low thermal conductivity. Combined with modern double or triple glazing, low-E coatings and argon gas fill, timber windows achieve whole-window U-values that match or exceed synthetic alternatives. The frame itself contributes to thermal performance — unlike aluminium, which requires thermal breaks to prevent heat loss.

Conclusion

Timber windows represent a genuine long-term investment. Yes, they cost more upfront. Yes, they require periodic maintenance. But they also last two to three times longer than uPVC, perform better thermally, look incomparably better, and are the only renewable window option available.

For period properties, conservation areas, eco-conscious homeowners, and anyone thinking beyond the next decade, timber remains the intelligent choice. The key is specifying correctly: right timber species for your application, appropriate glazing for your climate, and quality manufacturing from a reputable supplier.

At Timber Windows Direct, we manufacture bespoke timber windows in engineered pine, meranti and oak — supply-only, delivered nationwide. Every window is made to order for your specific openings, with factory-applied finishing and comprehensive technical support.

Ready to explore your options? Request your free quote and let’s discuss what works best for your project.

In this article, you’ll discover:

• What defines authentic Georgian window proportions and why they matter
• The history behind the iconic six-over-six glazing pattern
• Why slim glazing bars are essential for period accuracy
• How to spot common mistakes in Georgian window replacements
• The truth about sash horns and when they appeared
• Restoration standards for listed Georgian properties

Introduction

Walk down any Georgian terrace in Bath, Edinburgh, or Dublin, and you’ll notice something striking: the windows. Tall, elegant, perfectly proportioned — they’re as much a part of Georgian architecture as the symmetrical facades they sit within.

But here’s what many homeowners don’t realise. Those beautiful six-over-six sash windows weren’t just decorative choices. They were engineering solutions, born from the limitations of 18th-century glass manufacturing. And getting them right — whether you’re restoring originals or installing replacements — requires understanding why Georgians built them the way they did.

We’ve seen countless replacement windows on period properties that look… wrong. The proportions are off, the glazing bars too thick, or there are sash horns where there shouldn’t be any. These details matter, especially in conservation areas where planning officers know exactly what to look for.

This guide covers everything you need to know about authentic Georgian windows — from the historical context to the precise specifications that separate accurate reproductions from obvious imposters.

What Makes a Window Georgian?

The Georgian era spans 1714 to 1830, covering the reigns of George I through George IV. It’s a period that gave Britain some of its finest domestic architecture — and established window designs that still influence building today.

The Six-Over-Six Pattern

The defining feature of Georgian windows is the six-over-six glazing pattern. That’s six panes in the upper sash, six in the lower, creating twelve individual panes of glass separated by slim wooden glazing bars.

Why twelve panes? Simple economics and technology. In the 18th century, crown glass was expensive and could only be produced in small sheets. Larger panes meant more waste, higher costs, and greater risk of breakage during transport. Six-over-six represented the sweet spot — maximising light whilst keeping each pane to a practical size.

The typical pane in an early Georgian window measured roughly 10-12 inches wide by 14-16 inches tall. These proportions weren’t arbitrary. They reflected the available glass sizes and created the vertical emphasis that defines Georgian aesthetics.

Proportions and Symmetry

Georgian architecture is fundamentally about proportion and balance. Windows were positioned with mathematical precision, their spacing calculated to create harmonious facades.

The windows themselves follow strict proportional rules:

• Height-to-width ratio typically 2:1 or slightly taller
• Upper and lower sashes of equal size
• Glazing bars creating panes taller than they are wide
• Windows reducing slightly in size on upper floors

This last point catches many people out. Ground floor windows on Georgian townhouses are genuinely larger than those on the first floor, which are larger again than second floor windows. It’s a deliberate optical technique that makes buildings appear taller and more elegant from street level.

Glazing Bars: The 18mm-20mm Rule

If there’s one detail that immediately distinguishes authentic Georgian windows from poor reproductions, it’s the glazing bars. And frankly, this is where most replacement window companies get it wrong.

Why Slim Bars Matter

Original Georgian glazing bars — sometimes called astragals or muntins — typically measured just 18-20mm wide. Some early examples were even slimmer, around 15mm. This created the delicate, refined appearance that defines the style.

Modern reproductions often use bars of 25-30mm or more. To untrained eyes, the difference might seem trivial. To anyone familiar with Georgian architecture — including conservation officers — it’s immediately obvious. The windows look clunky, heavy, and unmistakably modern.

The thing is, achieving genuinely slim glazing bars requires skill. Thinner bars mean less structural material holding the glass in place. They demand precise joinery, quality timber, and proper understanding of how the forces distribute across the sash.

Ovolo vs Lamb’s Tongue Profiles

Georgian glazing bars used specific moulding profiles. The two most common were:

Ovolo — A simple quarter-round profile, common in earlier Georgian properties (roughly 1714-1760). Clean, understated, and relatively easy to reproduce.

Lamb’s tongue — A more refined double-curve profile that became fashionable from the mid-Georgian period onwards. Requires more skilled carpentry but creates a more elegant shadow line.

For sash windows in listed buildings, matching the original profile exactly is typically a planning requirement. Even in unlisted Georgian properties, using the correct profile dramatically improves authenticity.

The Sash Horn Question

Here’s something that trips up homeowners and even some window suppliers: sash horns.

Those small projections at the bottom corners of the upper sash — the ones you see on Victorian and Edwardian windows — didn’t exist in the Georgian period. None of them. If your “Georgian” replacement windows have horns, they’re historically inaccurate.

Why Horns Appeared Later

Sash horns emerged in the 1840s as a structural solution to a new problem: larger panes of glass. As cylinder glass manufacturing improved, windows could accommodate bigger individual panes. The classic Victorian pattern of two-over-two or one-over-one meant much larger, heavier sashes.

Horns strengthened the vulnerable mortise and tenon joint at the bottom of the upper sash — the point where the meeting rail joins the stiles. With twelve small panes, this joint experienced relatively low stress. With two large panes, it needed reinforcement.

Getting It Right for Georgian Properties

For authentic Georgian reproductions:

• No sash horns on any windows
• Meeting rails should be flush with stiles (no projection)
• The joint should be a traditional wedged mortise and tenon

If a supplier offers you Georgian-style windows with horns “for strength,” they either don’t understand the history or they’re using inappropriate construction methods. A properly built six-over-six sash doesn’t need horns — Georgians managed perfectly well without them for over a century.

Typical Georgian Window Dimensions

Georgian windows varied by building type, location, and date, but certain dimensions recur consistently enough to serve as guidelines.

Standard Opening Sizes

For a typical Georgian townhouse:

These are structural opening sizes. The actual sash dimensions would be approximately 60-70mm bigger in each direction to accommodate the box frame.

Box Frame Depths

Georgian box frames — the outer timber housing containing the sash weights and pulleys — were typically 100-120mm deep. This allowed space for:

• Inner and outer linings
• Sash weight compartments (both sides)
• Sash weights of appropriate mass
• Parting beads and staff beads

Modern slim-profile sash windows often use spring balances rather than weights, reducing frame depth to 60mm. While this can work for new-build period-style properties, it rarely satisfies conservation requirements for listed buildings.

Restoration Standards for Listed Buildings

If your Georgian property is listed — Grade I, II*, or II in England and Wales, or Category A, B, or C in Scotland — window replacement is heavily regulated.

What Historic England Recommends

Historic England’s guidance on windows in historic buildings emphasises:

• Repair over replacement wherever possible
• Like-for-like materials when replacement is unavoidable
• Matching original profiles, proportions, and details exactly
• Retention of historic glass where it survives
• Single glazing in most cases (though carefully designed double glazing is sometimes acceptable)

The key phrase is “preserve or enhance.” Any replacement window must preserve the character of the original or, ideally, enhance it by correcting previous inappropriate alterations.

Conservation Area Requirements

Even unlisted Georgian buildings in conservation areas face restrictions. Local planning authorities can require:

• Prior approval for window replacement
• Evidence that proposed windows match original specifications
• Specific materials (typically timber only)
• Authentic glazing patterns and proportions

In practice, this means cheap uPVC or aluminium replacements are almost never acceptable. Quality timber windows built to Georgian specifications are the standard expectation.

Common Mistakes to Avoid

Having worked with Georgian properties for years, we see the same errors repeatedly. Here’s what to watch for:

Glazing Bar Width

As mentioned, bars over 25mm look wrong. But equally problematic are bars that are too slim — under 15mm can appear flimsy and may not meet Building Regulations for structural glazing.

Incorrect Glass

Georgian glass had imperfections — slight ripples, bubbles, and variations in thickness. Modern float glass is perfectly flat and uniform. For the most authentic appearance, consider restoration glass with deliberate imperfections, though this costs significantly more.

Wrong Sash Proportions

Georgian sashes were almost always equal in height. Windows with a taller lower sash or shorter upper sash are Victorian conventions, not Georgian.

Inappropriate Hardware

Georgian windows used brass or iron fittings — simple sash lifts, face-fixed locks, and plain pulleys. Ornate Victorian hardware looks anachronistic.

Painting Schemes

Georgian windows were typically painted — white became fashionable from the mid-18th century, though earlier buildings often used darker colours. The bare wood look beloved of some modern restorations isn’t historically accurate.

Frequently Asked Questions

What is the typical glazing pattern for Georgian windows?

The characteristic Georgian glazing pattern is six-over-six — six panes in the upper sash and six in the lower, totalling twelve panes per window. This pattern resulted from 18th-century glass manufacturing limitations, where crown glass could only be economically produced in relatively small sheets. Earlier Georgian properties sometimes featured nine-over-nine or even twelve-over-twelve patterns, whilst later Georgian windows occasionally used larger panes as glass technology improved.

How wide should glazing bars be on Georgian windows?

Authentic Georgian glazing bars measure 18-20mm wide, with some early examples as slim as 15mm. This delicate proportioning is essential for period accuracy. Modern reproductions often use bars of 25-30mm, which immediately looks wrong to anyone familiar with Georgian architecture. For listed buildings or conservation areas, matching original bar widths is typically a planning requirement.

Did Georgian windows have sash horns?

No. Sash horns — the small projections at the bottom corners of the upper sash — are a Victorian innovation from the 1840s. They appeared when larger glass panes created heavier sashes requiring additional joint reinforcement. Authentic Georgian windows have flush meeting rails with no horns whatsoever. Any “Georgian” window with horns is historically inaccurate.

What’s the correct height-to-width ratio for Georgian windows?

Georgian windows typically follow a height-to-width ratio of approximately 2:1 or slightly taller, creating the elegant vertical emphasis characteristic of the period. Both sashes should be equal in height, and individual panes should be taller than they are wide. Windows on upper floors were deliberately smaller than those below — a proportional technique that makes buildings appear more elegant from street level.

Can I install double glazing in a listed Georgian property?

Possibly, but it requires careful design and Listed Building Consent. Historic England’s position is that single glazing is preferred for listed buildings, but sympathetically designed double glazing may be acceptable where it doesn’t harm the building’s significance. This typically means slim-profile units, authentic glazing bar widths, and retention of original box frame proportions. Each case is assessed individually by the local conservation officer.

What timber species is best for Georgian window restoration?

For historically accurate restoration, softwood (typically Scots pine or Baltic redwood) matches what Georgians actually used. For enhanced durability, engineered softwood offers better dimensional stability whilst maintaining authentic appearance. Hardwoods like oak weren’t commonly used for Georgian sash windows, though they’re sometimes specified for improved longevity in exposed locations.

Conclusion

Georgian windows represent a high point in British architectural design — elegant, proportioned, and purposeful. Whether you’re restoring originals or installing sympathetic replacements, understanding the details that define authentic Georgian glazing makes the difference between windows that honour your property’s heritage and ones that undermine it.

The six-over-six pattern, slim 18-20mm glazing bars, absence of sash horns, and correct proportions aren’t arbitrary historical details. They’re the visual language of Georgian architecture, and they’re what conservation officers, neighbours, and future buyers will notice.

At Timber Windows Direct, we manufacture bespoke sash windows to authentic Georgian specifications — correct proportions, appropriate glazing bar profiles, and traditional construction methods. Every window is made to order for your specific openings.

Get your free quote and let’s discuss how to get your Georgian windows right.

In this article, you’ll discover:

• Why condensation forms on windows (and why it’s not a fault)
• The difference between interior, exterior, and between-pane condensation
• Four practical solutions ranked by cost and effectiveness
• When upgrading your glazing actually makes sense

Waking up to windows streaming with water is frustrating. And if you’ve got beautiful timber windows, it’s natural to worry about moisture causing damage.

Here’s the thing: condensation on windows isn’t usually a window problem. It’s a ventilation and humidity problem. Your windows are simply the coldest surface in the room — where moisture in the air turns back into water droplets.

This guide covers all the causes and solutions, so you can tackle the problem properly.

What Causes Window Condensation?

Condensation is water vapour turning back into liquid when it meets a cold surface. The scientific term is ‘dew point’ — the temperature at which air can no longer hold its moisture. Three factors determine whether you get condensation:

1. Indoor humidity levels — a family of four produces 10-15 litres of water vapour daily through breathing, cooking, and washing
2. Surface temperature — how cold the window glass is
3. Ventilation — whether moist air is being replaced with drier air

Modern homes suffer more because they’re airtight. Older houses were draughty — not ideal for comfort, but excellent for preventing condensation. When you insulate and draught-proof without adding ventilation, moisture has nowhere to go.

Interior vs Exterior vs Between-Pane Condensation

Condensation on the Inside

Interior condensation — moisture on the room-facing surface — is the most common type. It indicates high indoor humidity combined with cold window surfaces. Particularly common in bedrooms (we breathe out moisture overnight), kitchens, and bathrooms.

Condensation on the Outside

Here’s something that surprises many homeowners: external condensation is actually a sign of good thermal performance. It happens when the outer glass is so well insulated from your home’s heat that it stays colder than the outside air. If you’ve recently upgraded to low-e glazing and see morning condensation outside, don’t worry — it clears as the sun warms the glass.

Condensation Between the Panes

Moisture trapped between the glass panes means the seal has failed. The inert gas (usually argon) has been replaced by humid air. Failed sealed units need replacing — the good news is that with timber windows, you can usually replace just the glazing unit rather than the whole window.

Four Solutions: From Simple to Significant

Solution 1: Improve Ventilation

The single most effective solution. You need moist air out and drier air in.

Trickle vents are small ventilators built into window frames, providing constant background ventilation without significant heat loss. Building Regulations require them in new windows precisely because they’re so effective. Keep them open — closing them defeats the purpose.

Extract fans in kitchens and bathrooms should run during cooking/bathing and for 15-20 minutes afterwards. Humidistat-controlled fans that activate automatically are particularly useful.

Window opening: Even in winter, five minutes of ‘purge ventilation’ (windows wide open) is more effective than leaving them on a crack all day.

Solution 2: Reduce Humidity at Source

Sometimes you’re producing more moisture than ventilation can handle:

• Drying clothes indoors: One load releases ~2 litres of water. Use a vented tumble dryer or dry in a closed room with window open.
• Cooking: Cover pans and always use the extractor.
• Showers: Keep bathroom door closed; run fan during and after.
• Unflued gas heaters: Produce huge amounts of water vapour. Avoid if possible.

Solution 3: Use a Dehumidifier

If ventilation alone isn’t enough — particularly in older properties or basements — a dehumidifier can help. Modern refrigerant models extract several litres daily and cost around 3-5p per hour to run.

Aim for 40-60% relative humidity. Below 40% causes dry skin; above 60% encourages condensation and mould. A simple hygrometer (under £10) lets you monitor levels.

Solution 4: Upgrade Your Glazing

If you’ve got single glazing or failed sealed units, upgrading makes sense. Modern double glazing with a decent U-value (1.4 W/m²K or better) keeps the inner glass warmer, making condensation less likely.

Triple glazing and argon-filled units perform even better. But honestly, for most UK homes, good double glazing combined with adequate ventilation solves the problem.

Quick Diagnosis Guide

Where’s the condensation? Here’s what to do:

• Inside surface → Improve ventilation and reduce humidity sources
• Outside surface → Nothing to fix — your glazing is working well
• Between panes → Seal has failed — replace the glazing unit
• Throughout house → General ventilation problem — consider whole-house approach

Frequently Asked Questions

Why do I get condensation on my new windows?

New windows are more airtight than old ones. Less background ventilation means humidity builds up. It’s not a fault — you just need to adjust habits. Keep trickle vents open and ventilate briefly each day.

Is condensation damaging my timber frames?

Occasional condensation won’t harm properly finished timber. Persistent heavy condensation pooling on sills can eventually penetrate the finish. Wipe away pooled water regularly and maintain frames with microporous paint.

What humidity level should I aim for?

Keep relative humidity between 40-60%. Below 40% causes dry skin and respiratory issues; above 60% encourages condensation and mould. A cheap hygrometer helps you monitor this.

Will secondary glazing help?

Yes — secondary glazing warms the primary window and reduces humidity transfer. A good solution for listed buildings where replacing original windows isn’t permitted.

Getting Condensation Under Control

Window condensation comes down to moisture meeting cold surfaces. Address the moisture, warm up the glass, or improve ventilation — and the problem improves. Start simple: open trickle vents, use extract fans, avoid drying clothes indoors. If that’s not enough, add a dehumidifier or consider upgrading your glazing.

At Timber Windows Direct, all our windows come with integrated trickle vents and high-performance sealed units. Get in touch to discuss replacement windows for your property.

In this article, you’ll discover:

• How windows impact first impressions and kerb appeal
• Why buyers pay more for period-appropriate materials
• The EPC effect: how window efficiency affects property value
• What estate agents say about timber vs uPVC
• Where timber investment makes the biggest difference

“Will I get my money back if I sell?” It’s one of the first questions homeowners ask when considering timber windows over uPVC.

The short answer: in most cases, yes — and often more. But the real picture is more nuanced than a simple ROI calculation. Timber windows affect property value in several ways, and understanding these helps you make the right decision.

Kerb Appeal: The 10-Second Window

Estate agents will tell you: buyers make up their minds within seconds of seeing a property. And what do they see? The front elevation. The windows.

Windows typically cover 15-25% of a building’s façade. They’re impossible to miss. And while buyers might not consciously think “those are timber windows,” they absolutely register the overall impression — proportions, detailing, quality.

What Buyers Notice

• Proportion and design: Timber allows for slim glazing bars and authentic period profiles that uPVC can’t replicate
• Colour and finish: Timber can be painted any colour; uPVC is limited and fades over time
• Condition: Well-maintained timber looks premium; ageing uPVC looks cheap
• Consistency: Windows that match the property’s character vs obvious replacements that jar

On period properties especially, uPVC windows can actively detract from value. They signal “budget upgrade” to experienced buyers.

Period Properties: Authenticity Commands a Premium

For Victorian, Edwardian, Georgian, and Arts & Crafts properties, original or sympathetic replacement windows are expected by buyers at the upper end of the market.

What the Data Shows

Properties in conservation areas typically sell for 5-15% more than equivalent properties outside. Part of that premium reflects the architectural integrity that comes with appropriate materials.

Conversely, period properties with uPVC windows often sell below comparable homes. Estate agents report that buyers factor in the cost of “putting right” the windows — and then some, because it’s a hassle they’d rather avoid.

The Premium Market Effect

In higher-value areas, buyer expectations increase dramatically. A Victorian townhouse in a desirable London neighbourhood? Buyers expect timber sash windows. Anything else is a negative.

We’ve had customers tell us their estate agent specifically recommended upgrading from uPVC to timber before marketing — the agent knew it would make a material difference to offers.

Energy Efficiency and EPC Ratings

With proposed legislation potentially requiring minimum EPC ratings for sales and lettings, energy efficiency has become a valuation factor.

Modern timber windows with quality double glazing achieve U-values around 1.2-1.4 W/m²K — better than most uPVC at equivalent price points. Combined with low-e glass and argon filling, timber windows can significantly improve a property’s EPC rating.

Research suggests each EPC band improvement adds roughly 3-5% to property value. For a £400,000 home, moving from D to C could mean £12-20,000.

Longevity: The Investment That Keeps Giving

Here’s something buyers increasingly understand: timber windows last 60+ years. uPVC? 20-30 years.

For an informed buyer, uPVC windows installed 15 years ago represent a liability — replacement within the next decade. Timber windows of equivalent age have decades of life remaining.

This matters for valuations. Estate agents increasingly note window type and condition. “Original timber sash windows, well maintained” is a positive. “uPVC replacement windows, 2008” is neutral at best.

What Estate Agents Actually Say

We asked several estate agents operating in areas with mixed housing stock. Here’s the consensus:

On period properties: “Timber windows are expected. uPVC is a negative that gets flagged in particulars — often unspoken but definitely factored into offers.”

On conservation areas: “Buyers actively look for properties with correct windows. They know getting planning for changes is difficult, so finding a property that’s already right commands a premium.”

On modern properties: “Less differentiation here. Quality matters more than material. But even on newer builds, timber signals ‘premium’ in a way uPVC doesn’t.”

On ROI: “You won’t necessarily get every pound back on a modern property. But on period homes, especially in good areas, timber windows can return 100%+ of investment through increased sale price.”

Where Timber Investment Makes the Biggest Difference

Strongest return:

• Listed buildings (often required)
• Properties in conservation areas
• Victorian, Edwardian, Georgian homes in desirable areas
• Premium developments where quality is expected

Good return:

• Character properties generally
• Properties in affluent areas
• Homes you plan to keep long-term (value compounds)

Neutral to modest return:

• Standard modern housing
• Properties you’ll sell within 5 years
• Areas where buyers prioritise price over quality

Frequently Asked Questions

Windows as Investment

Timber windows aren’t just a purchase — they’re an investment in your property. The returns come through kerb appeal, period authenticity, energy efficiency, and sheer longevity.

Whether you’re planning to sell soon or stay for decades, timber windows make financial sense for most period and character properties. And even where the immediate ROI is modest, you get daily benefits — aesthetics, comfort, performance — that spreadsheets don’t capture.

At Timber Windows Direct, we manufacture bespoke windows in engineered pine, meranti, and oak. Get in touch to discuss how we can add value to your property.