HistoricWindowGuide

A brief illustrated history of window development from the Middle Ages to the present

Tredington Court Tredington

Why are windows important?

developed in markedly differing waysin different regions (the further fromLondon, the longer advances took toreach it). Consequently highly localised types of vernacular windowdeveloped in some areas and suchwindows contribute enormously tocreating a sense of place or localidentity.

the manufacturing of glass.

Consequently the importance ofwindows does not just rest in their overall appearance, but in details such as their construction and materials, their fittings andmechanics, and even the very glassthat is the reason for their existence.The type of windows that a buildingcontained usually reflected the statusof that building, and that of theowner. Within a single building,windows of differing status oftenreflected the social hierarchy of theinternal spaces, from the principalreception rooms on the ground orfirst floors, to the servants rooms inthe basement or attic.

Vernacular window design, whichwas usually far slower to respond tothe latest advances in fashion, often

One of the most common questionsasked in relation to old windows isWhy are windows so important?There are a number of answers to thisquestion:

Windows are, in effect, a buildingseyes; often a buildings mostprominent feature, they are one of themost significant components in determining a buildings characterand appearance.

Window design has evolved continuously over the centuries, sowindows can be of invaluable assis-tance in dating buildings, and laterphases of alteration.

Window design is closely related tothe evolution of architectural styles,framing materials and, most impor-tantly, to technological advances in

Pre-Sixteenth Century

Before the sixteenth century, mostwindows were constructed from stonemullions or timber frames withunglazed openings; these could beclosed with either sliding or foldingwooden shutters, or oiled cloth orpaper, or even thin sheets of horn.Only the wealthiest houses couldafford to have glazed windows; thesewould have been constructed fromsmall panes of glass, or quarrels, heldin a lattice of lead strips or cames.This lead lattice was quite soft, so itwas usually reinforced with steelbars, either vertically (stanchions)or horizontally (saddle bars).

Stone mullions were moulded onboth the inside and outside faces,usually with either a chamfer orcavetto moulding; timber windowframes, which were usually constructed from oak with peggedmortice and tenon joints, weresimilarly moulded in imitation ofmore expensive stone.

Little Museum, Tewkesbury

Detail of Leaded Glazing

9 Church Street Tewkesbury

CPre-16th

Mullion Details

Ogee Moulding17th & 18th Century

Beaded 17thCentury onwards

Chamfer Mouldingall dates

Cavetto Mouldinglate 16th Century

Chamfer Mouldingall dates

Ovolo Moulding17th Century

Tim

ber

Ston

e

Sixteenth Century

This century, which was a period ofgreatly increased stability and prosperity due to the newly established Tudor dynasty, saw a considerable increase in window size.These large windows were subdivided into smaller openings, orlights by mullions (vertical bars ofmasonry or timber) and transoms(horizontal bars). To achieve anopening window, a wrought-ironframe would be set into the mullions,to which a smaller, opening frame, orcasement , would be hinged; thiscould be latched shut with an ironcatch, or held open with an iron stay.The leaded glazing would be attachedto the casement in opening lights, orset into the mullions in fixed lights.

As the century progressed, and glassbecame more readily available,windows in wealthy householdsbecame ever larger and more extrava-gant as the Elizabethan aristocracyvied to display their wealth. Insmaller houses glazing remained rare,but nevertheless was still morecommon than in previous centuries.In this century the ovolo mouldingbecame the standard form for bothstone and timber windows.

C16th

88A Church Street Tewkesbury:wrought iron casement & stay

Stanway House

64 Barton Street, Tewkesbury: timber mullioned & transomed windows 17th Century

Details of Catch & StaysOvolo Moulding

Seventeenth Century

The accession of the house of Stuart,in 1603, brought about renewedcontact with the Catholic countries ofEurope, enabling Caroline artists, likeInigo Jones, to bring back first-handexperience of the Italian Renaissance.As a result of this new influencewindows began to conform to newclassical ideals; they became tallerthan they were wide, with such widthto height ratios as 1:1 or 1:2. Thesewindows were typically divided intofour lights by a single mullion andtransom; these could be masonry, butas the century progressed, they wereincreasingly constructed from timber(a cross-casement window).Smaller windows were usually lowerand wider, with several mullions andno transoms, but otherwise theydiffered little from the cross-casement windows.

Seventeenth-century stone mullionsusually still had ovolo mouldings, although localised variationsoccurred. However, as timber frames became more fashionable than stonemullions, they stopped imitatingthem; the mullions and transomsbecoming narrower, glazing was nowplaced almost flush with the externalface of the window and mouldingswere confined to the internal face(usually ogee or reverse ogeemouldings). These changes alloweda larger area of glazing and made theframe far less conspicuous.

C17th

Snowshill Manor: stone cross casement with leaded lights. Mullions show Renaissance influence

Old Rectory Dumbleton: timber crosscasement early 18th Century

Lower Moorcroft Farm Minsterworth:early 18th Century

A further Act in 1774 decreed that allsash-boxes be concealed within the fabric of the wall (a concealed-boxsash). However these acts were nonetoo scrupulously adhered to, particularly in the provinces.

Seventeenth and early-eighteenth-century sashes were always externally painted; usually off-whiteor pale stone colours, although onsome very wealthy houses they weresometimes painted black and embellished with gold leaf.

The expense of crown glass kept itbeyond the reach of the majority ofthe population, so casement windowswith leaded glazing remained verycommon throughout the seventeenthand much of the eighteenth centuries.

with a flat external face and an ovolomoulded internal face (the thicknesswas to support the thick and heavyglass); they would divide thewindows into as many as sixteenpanes in the upper sash and twenty inthe lower (expressed as a sixteen-over-twenty sash window).

Most early sashes were set almostflush to the external face of the wall(a flush-box sash), but the BuildingAct of 1709 banned these, decreeingthat windows should be set back intothe opening by four inches (arecessed-box sash).

In 1674 the introduction of crownglass led to a form of cross-casementwindow that had larger panes of glassheld in timber or iron glazing barsrather than small panes in a leadedlattice. However, although this typeof window became the basis forwindow design throughout the eigh-teenth century in France, in Britain itwas soon replaced by the newlyinvented sash.

The sash window consisted of twosashes, or glazed frames; the frontone would be suspended in the tophalf of the frame, and the rear wouldclose the bottom half. Better qualitysashes would be hung on cordsattached to counter-weights that wereconcealed in a hollow part of theframe (the sash-box), allowing thesashes to slide up and down (adouble-hung sash); simpler sasheshad the upper sash fixed to the frame,and counter-weights or even pegs orprops to hold the lower sash open (asingle-hung sash). Seventeenth-century sashes were always timber,usually oak or pine, with a grid oftimber glazing bars to hold the glass.These glazing bars would be up tothirty-five millimetres thick, often

Snowshill Yorkshire sideways slidingSash

Double hung sash details (reproduced with kind permission of English Heritage)

Flush box sash window

Recessed box sash window

Concealed box sash window

CEighteenth Century

In the early years of the eighteenthcentury, the sash altered little fromthose of the latter seventeenthcentury. However, as the centuryprogressed sash design evolved; theycame to be made almost exclusivelyfrom pine (usually Baltic pine); as thequality of glass available improvedand panes became thinner, the widthof the glazing bars began slowly toreduce; and the common moulding for the internal face of the barsbecame the lambs tonguemoulding. By the end of the century,timber glazing bars on very finesashes were as little as ten millimetres wide, and there was someexperimentation with making glazingbars, or even entire windows, fromiron or copper, in an attempt to makethem ever more slender. From the1770s, the introduction of early plateglass lead to further increases of panesize and reduction of the number of glazing bars, although the initial costconfined plate glass to the rich.The size of mid-eighteenth-centurysash windows began to standardise, the usual Georgian arrangementbeing a six-over-six; although therewas still considerable variation onboth grand houses and small provincial houses, where three-over-sixes and eight-over-eights where notuncommon, although the very largesashes of the previous centurybecame almost unheard of.

77 Church Street Tewkesbury: early 18th Century flush box sash windows

Details of Glazing Bars

Wallsworth Hall Twigworth: mid 18thCentury ovolo moulded sash windowwith rubbed brick lintel, stone cill andkeystone

Wallsworth Hall Twigworth: window toprincipal elevation with classical stonesurround

18th

17th Century Ovolo (early)

Broken Lambs Tongue

Gothic OvoloLambs Tongue

Throughout the century sashesbecame increasingly less expensive;by mid-century they were appearingin quite humble houses and by theend of the century they were standardon even the smallest workersdwellings. Whilst they were paintedpale colours in the early part of thecentury, from the 1760s blackbecame fairly popular (particularly inashlar stone or stuccoed houses) andthe use of greens, browns andgraining effects were not uncommon.

Casement windows became increas-ingly rare throughout the eighteenthcentury, but survived predominantlyin small, rural dwellings and in thelate-eighteenth and early-nineteenth-century vogue for cottageorne(small ornamental cottages designed specifically to look romanti-cally quaint, usually in the gardens orparks of country houses). Thesewindows increasingly had crownglass and timber glazing bars andcasements, rather than the leadedglazing and wrought-iron openingcasements of earlier windows.

32 Church Street Tewkesbury: 1813a remarkable elongated sash to lightthe staircaseTimber casement window replacing leaded lights in a stone mullioned frame

62 North Street Winchcombe: typical Georgian 6 over 6 sash windows

Nineteenth Century

In the early years of the nineteenthcentury, the Regency era, there wassome experimentation with thepatterns of glazing bars in an attemptto break away from the simple grid-like arrangements of the previouscentury. The use of narrow marginlights became common (these werelong, thin panes of glass that ranaround the edge of the window like aborder); they were often filled withnewly fashionable coloured glass(particularly popular were pink, lilac,blue, purple, red or amber). Glazingbars were even curved into interlocking pointed arches to imitateGothic tracery.

The size of windows began to grow,to flood rooms with light and allowaccess to newly fashionablebalconies; many eighteenth-centurysashes had their sills lowered tobecome full-length or were evenreplaced by French windows.

The increasing availability of plateglass meant that the numbers ofglazing bars in windows was continu-ally being decreased, or, for the very rich, done away with altogether.After the accession of Victoria, in1837, plate glass became far more common as improved methods ofmanufacture made it less expensive;by the mid-century most sashes eitherhad only a single, central glazing bar,or none at all. To compensate for theincreased weight of the plate glass,and the loss of strength from the lack

Late 18th Century curved gothic glazing bared sashes in Venetian windows at9 & 10 Barton Street, Tewkesbury with flush boxes. No 11 (right) has later 19thCentury recessed tripartite sash windows

C19th

Abbey Tea Rooms Tewkesbury, margin light casement window

of glazing bars, horns were intro-duced onto the sashes to strengthenthem; such horns had never beenused before the mid-nineteenthcentury.

In grander buildings, the Victorianslove of the past led to sash windowsoften being disguised by beingrecessed behind stone-mullion frames that approximated historical styles; such sashes were usually painted quite dark colours, deep greens, browns, or grained to approximatemore expensive hardwoods.

In the second half of the century,following on from the GreatExhibitions Crystal Palace (1850),there was some experimentation withsetting plate glass in iron frames,creating very twentieth-century-looking windows, but this did notbecome popular in houses and waspredominantly confined to conserva-tories, hot houses and industrialbuildings. However, more histori-cally-inspired wrought-iron frames,set behind stone mullions, didbecome quite common in the Gothicrevival style that became fashionablein the second half of the century.Elaborate cast-iron casements, whichimitated the leaded quarrel glazing ofearlier centuries by dividing the windows into many small rectangularor diamond-shaped panes of glass,also became popular, particularly onestate cottages.

The latter part of the century saw therise of two new historical styles, theArts and Crafts movement and theQueen Anne movement; under theformer, genuine leaded-lights againbecame popular, set in stone mullionsor oak frames; under the latter, white-painted small-pane sash windows.Towards the end of the century, thedistinction between these two stylesbecame blurred, creating a hybridthat often contained both elementswithin the same building, sometimeswithin the same window.

1905 Chance Street Primary SchoolTewkesbury: concealed box sashwindows with horns

Ropewalk Tewkesbury: Victorian sashwith horns

Cotteswold Road Tewkesbury: hybridsash design typical of Edwardianhouses

19 High Street Tewkesbury (Lloyds TSB Bank): built in 1921 in the Tudor revivalstyle with intricate leaded light oriel windows

19th Century cast iron casementsmimic leaded lights of previouscenturies

Twentieth Century

The pre-war and inter-war periods ofthe twentieth century saw a splitbetween revived-traditional andmodernist windows.

The revived-traditional windowswere a continued evolution of theArts and Crafts and Queen Annestyles and eventually evolved in twodirections: the first simplified tobecome the common style for mostinter-war housing estates, with timbercasements, often with small panels ofleaded and coloured glass in doorsand at the top of windows; the secondevolved into a late-seventeenth/early-eighteenth-century revival, and wasparticularly popular for publicbuildings, where large multi-panedsashes again became common.

At the same time, the modernistwindows, influenced by the Art Decostyle, were made from recentlydeveloped hot-rolled steel; theseCrittal windows, manufacturedusing the latest technology, produceda simple, functional window of strik-ingly modern appearance, in keepingwith the crisp, minimalistInternational Style.

C20thBishops Drive Bishops Cleeve: metal framed casement windows 1948

Brockworth Airfield control tower c. 1942 (now demolished) in the Art Deco style

Crittal windows: GAC Gloucester Aircraft Co. Brockworth

In the post-war period, functionalismbecame the leading design principle.Typical features of post-war windowswere simple white-painted softwoodframes, usually of very plain,unmoulded timber section with storm-proofed opening casements andstorm-proofed top-hung fanlights;they often formed picture windows,with a single, very large sheet ofglass. Windows of similar designwere also constructed fromaluminium. On larger buildings theproduction of large sheets oftoughened glass saw the introductionof curtain walling, where buildingswere entirely clad in glass.

The 1980s saw the arrival ofPlanar glazing; using this system the glass is not held in frames, but isattached, by bolts or vacuum pads, toan internal armature, often of steeltubing or cables; silicon sealantbetween the panes of glass makesthem weather-tight. This decade alsosaw the arrival both of sealed-unitdouble glazing, and the unplasti-cised-polyvinyl chloride (U.-P.V.C.)frames which invariably hold them. Planar Glazing

Millennium Houses Tewkesbury

The Hyde Winchcombe: storm-proofed picture windows withtop hung fanlights

sheets in a furnace, cooled on a bedof sand and polished. The glassproduced has a distorted, rippledeffect and greenish tint when lookedthrough, often with some air bubblesand other imperfections.

Crown GlassThe first recorded crown glass inEngland was in 1674, and it remainedthe standard high-quality glass untilthe 1830s. The molten glass wasblown into a bubble, this is thenpierced and the punty, or rod, spun,flinging the malleable glass out into adisk of approximately four feet indiameter. The glass was cooled onthe punty, before being cut intopanes; the central bullion (or bullseye), where the rod attached, wasusually discarded, as were the curvededges. Crown glass was a far finer,clearer glass than that produced bythe preceding method, although itcould still have a slightly rippledtexture; its introduction heralded theend of the use of leaded glazing inwealthy households.

Cast Glass The technique of pouring moltenglass into flat moulds to create largesheets of cast glass, a technique usedby the Romans, was rediscovered inthe late seventeenth century in

France, and was soon being used inthe windows of the new royal apart-ments at Hampton Court Palace(1689-94); however, the labourrequired to pour and then polish castglass made it extremely expensive,and it was used more for decorativemirror-glass than for windows.

Plate or Cylinder-Sheet GlassPlate glass was first made in Britainin 1773, although it did not becomewidespread until the 1830s, whenChance Brothers of Stourbridge (wholater supplied glass for the CrystalPalace) industrialised the traditionaltechnique of making cylinder glass,to produce large sheets of high-quality and relatively inexpensiveplate glass. The rippled effect ofearlier glasses was greatly reduced,although when viewed obliquely,reflections still distort, rippling acrossthe surface.

Drawn GlassThis was invented in 1904 by aBelgian, Emile Fourcault, and laterimproved by several Americancompanies. The process involveddrawing sheets of glass through a slotin a tank of molten glass up overrollers and into a cooling chamber.

Float GlassSince 1959, the standard techniquefor making sheets of glass has beento pour the molten glass onto thesurface of molten tin, where itfloatsout to create an even sheet, with aperfectly smooth, featureless surface.

Old cylinder and crown glasses areirreplaceable. They are thin andeasily broken and should not beremoved from their original framesunless absolutely necessary. Ifremoval is unavoidable, paintsolvents, soldering irons, infra-redheaters or even household bleach canbe used to soften old putty; in allcases great patience is required as itmay take many applications to softenthe putty sufficiently.

Glass

Because of the transparent nature ofclear glass, few people pay it muchattention as a material in its ownright; it is something that we lookthrough, not at. As a result, it is oftenundervalued, and needlessly smashedout of windows on the excuse that itis only glass and easily replaceable.However, old glass is of considerablehistoric and visual interest. It is anintegral part of the fabric and historyof old windows as advances in glassmanufacturing were usually theprincipal reason for changes inwindow design. Old glass, with itsrippling transparency, dancing reflec-tions and greenish hue, contributessignificantly, if subtly, to thecharacter and appearance of oldbuildings, giving a far more livelyand interesting display than the featureless, static qualities of unre-lentingly uniform, modern glass.

The principal forms of glass are:

Cylinder, Broad or Muff GlassThis was the only glass manufacturedin England before 1674; it wasinvented in Germany in the 11thcentury, although the date of its intro-duction into England is unknown.The molten glass was blown and thenswung to form a cylinder; this was then cut, reheated and flattened into

Glass Blowing

Useful Contacts

English HeritageConservation TeamSouth-West Region29 Queens SquareBristolBS1 HND0117 9750700

Tewkesbury Borough CouncilCouncil OfficesGloucester RoadTewkesburyGL20 5TT01684 27209701684 272060

The Society for the Protectionof Ancient Buildings (S.P.A.B.)37 Spital SquareLondonE1 6DY020 73771644

The Georgian Group6 Fitzroy SquareLondonW1P 6DX020 73871720

The Victorian Society1 Priory GardensLondonW4 1TT020 89941016

The Twentieth Century Society70 Cowcross StreetBedford ParkLondonEC1M 6EJ020 72503857

Glossary

Arts & CraftsArtistic movement that flourishedin Britain from c.1851 to c.1939,that rejected industrial mass-production in favour of traditionalcraftsmanship

Art DecoA geometric modernist stylepopular in the 1920s and 30s; itdepended upon the latest technology and materials, anddecoration was stylised

CameSlender strips of lead, H shapedin section, which hold quarrels(q.v.) of glass in leaded glazing

CarolinePertaining to the reign of Charles I(1625-49)

CasementThat part of a window frame thatswings open on hinges; tradition-ally they were wrought iron or timber. A casement window is awindow that contains side-hungopening casements

CommonwealthPertaining to the republican period(1649-60) between the reigns ofCharles I and Charles II

ElizabethanPertaining to the reign ofElizabeth I (1558-1603)

FacadeAny exterior elevation of abuilding, but particularly the mainelevations

FretworkA trellis-like ornament of repeatinggeometric patterns; common inGreek and Chinese design, bothof which were influential in Britainin the latter 18th and early 19thcenturies.

GeorgianPertaining to the reigns of GeorgeI, II & III (1714-1820), andsometimes George IV (1820-30);overlaps with the Regency (q.v.)

Glazing barSlender timber bars, with a deco-rative moulding on the inner face,that form a grid-like frameworkthat holds panes of glass within atimber window frame

GothicTerm used to describe the architectural styles commonthroughout northern Europe fromthe 12th century to the 16thcentury. Those used in Britainwere: Early English (c.1180-c.1280), Decorated-geometric(c.1250-c.1300), Decorated-curvilinear (c.1300-c.1350),Perpendicular (c.1350-c.1550)

Gothic RevivalSerious revival of the Gothic style(strongly linked to Christianmorality); the predominant style in Britain from the 1830s to the1860s, it was more scholarly thanthe Gothick (q.v.), the fourdifferent phases of Gothic (q.v.)were clearly differentiated

GothickName commonly applied to thelight-hearted Gothic revival of the18th and early 19th centuries, distinguished from the later GothicRevival (q.v.) by its delicate,playful nature; it often confusedthe different phases of Gothic(q.v.)

Quarrel/quarrySmall pane of glass held within agrid-like pattern of lead cames(q.v.)

PoliteDescribes buildings that are builtto a specific fashion or style, withlittle dependence upon localtradition or materials; opposite ofvernacular (q.v.)

Queen AnnePertaining to the reign of QueenAnne (1702-14)

Queen Anne StylePopular from the 1860s, it was afree interpretation of the style ofthe Queen Anne (q.v.) era

RegencyThe style of the Regency era,c.1800-c.1830 (the actualRegency was technically 1811-1820)

RestorationPertaining to the reigns of CharlesII & James II (1660-88)

Saddle barA horizontal iron bar set into awindow frame, to which leadedglazing is tied

SashThat part of a window frame thatslides up or down, usually coun-terbalanced on weights. A sashwindow is a window that containssuch sliding sashes

StanchionA vertical iron bar set into awindow frame to support leadedglazing

StayA horizontal metal bar thatattaches between the windowframe and the casement to holdthe latter open

TerracottaUnglazed, baked clay; often usedfor decorative details on buildings.Common in the 15th and 16th centuries, and again in the19th and early 20th centuries

TransomA horizontal bar dividing a windowinto two or more lights (q.v.)

TudorPertaining to the Tudor dynasty,1485-1603, although things per-taining to Elizabeth Is reign(1558-1603) are more normallyreferred to as Elizabethan (q.v.)

VernacularDescribes buildings that are builtfrom local materials according tolocal traditions; buildings thathave few pretensions towards architectural grandeur; opposite ofpolite (q.v.)

VictorianPertaining to the reign of Victoria(1837-1901)

William & MaryPertaining to the joint reign ofWilliam III (1688-1702) & Mary II(1688-94)

HornsSmall projecting spurs of timberon a sash window (hanging downfrom the top sash and projectingup from the bottom sash), introduced from the mid-19thcentury to strengthen the joints

International StyleModernist style that evolved fromthe Art Deco (q.v.), it pared downall ornament in line with the principles of form and function; itwas the origin of most modernarchitecture

JacobeanPertaining to the reign of James I(1603-25)

Lambs tongueMoulding common on 18thcentury glazing bars (q.v.)

LightThe areas or compartments withina window, framed by mullions,transoms, or glazing bars (q.v.),through which light is admitted

Margin lightsA narrow window flanking a largerwindow or door; or narrow panesof glass around the edge of awindow composed mainly oflarger panes of glass

MullionA slender pier that forms thevertical division between the lights(q.v.) of a window

OgeeA shape common in theDecorated (curvilinear) style; alsoa popular moulding on timbercasement windows in the 17thand 18th centuries

OvoloA moulding common on 16thcentury mullions

The Conservation Team atTewkesbury Borough Council

Council OfficesGloucester Road Tewkesbury

Glos GL20 5TTTel: 01684 295010 Fax: 01684 272067

Email: buildingconservation@tewkesburybc.gov.uk

Forthampton Court

Produced by the Forward Planning Unit Tewkesbury Borough Council Tewkesbury Glos GL20 5TTFront Cover (clockwise) Millennium Houses Tewkesbury, Stanway House & 32 Church Street Tewkesbury