i n f o r m a t i o n s h e e t

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The Repair and Replacement of Tradi onal and Historic Windows

Introduc onThis Informa on Sheet is intended to act as a guide to those considering the repair or replacement of windows in historic buildings, whether listed or within designated Conserva on Areas. The principal types of windows referred to are sliding sash and casement windows; these are the most common historic styles evident within the County Borough. Other types and styles of window do exist and whilst the general principles outlined within this Informa on Sheet will apply, further specialist advice may be necessary in some instances.

Why are windows so important?Windows form one of the most signifi cant construc onal elements of a building and their style and propor on vitally aff ect the character and appearance of a building and its surroundings. Windows also provide important evidence of the origins and historic development of a property.

The altera on of windows may seem to have insignifi cant eff ect but even simple changes can impact upon the whole appearance of a building and detract from the tradi onal and historical character of the building and the surrounding area. The detailing of any repairs and of replacement windows is

therefore crucial to the sympathe c conserva on of Wrexham’s rich architectural heritage. Buildings which retain their tradi onal appearance are o en more desirable and sought a er and unsympathe c altera ons may impact upon the fi nancial value of the property.

September 2017

General Principles to consider Repair before replacement - Repair, par cularly of original windows, should always be the fi rst considera on. Most can be repaired and this is the best way of conserving the character and fabric of a historic building.

Like for like replacement - Where original and tradi onal windows are beyond the repair of a skilled joiner then replacement on a like for like basis, that is an exact copy of the exis ng window, should be the next op on.

Use appropriate methods of repair - Methods of repair should be appropriate to the window material and the age of the window. Using original techniques helps ensure compa bility in terms of performance and design. Tradi onal techniques such as splice repair and use of linseed oil pu y are encouraged. The use of modern compounds and wood fi llers will not be accepted.

Retain original window furniture - Window furniture forms part of the intended window design. Where replacement is necessary and original window furniture exists this should be retained, repaired and reused as far as possible. Any necessary new window furniture should match the designs, size and material of the original.

Maintain the original posi on of the window frame within the reveal - The posi on of a window within the reveal not only contributes to the character and appearance of an eleva on but also provides evidence as to the age and development of the building.

Regular maintenance - Windows require regular maintenance and checks to ensure their longevity. Regular checking can draw a en on to any poten al problems such as rot or failure of elements of the frame, and can prevent the need for expensive and complete replacement. Redecora on maintains the tradi onal character and appearance and can help retain the maximum value of the property.

Avoid introducing modern-style windows - Most modern window types, such as the ‘standard’ 1.8 metre wide frames and p-opening lights are only appropriate in modern buildings and almost always look out of place and incongruous in historic buildings destroying the original design inten ons.

Avoid standard profi le double glazed units - The introduc on of standard profi le double glazing can completely alter the propor ons of the window frame and size of the glazing bars and frame necessary to carry the

head sash box Components of a sash window

glazing bars sillbo om rail

counter weight

sash cord

pulley wheels

heavier units. They can therefore signifi cantly alter the overall appearance of the building. Slimmer profi le double glazing systems are being developed which may be acceptable in some instances.

Avoid PVCu windows - PVCu is not a tradi onal building material and is generally unsuitable for use in historic buildings as it nega vely aff ects the appearance through the chunkier frames and sheen fi nishes. Arguments that PVCu is more sustainable and environmentally friendly will not be accepted as suffi cient jus fi ca on for its use in historic buildings.

Consider other methods of insula on - Some window openings can accommodate secondary glazing which can be removed in the warmer summer months. Draught proofi ng and weather stripping exis ng windows can also aid thermal insula on as can heavy, lined curtains.

RepairSympathe c and careful repair is always preferable to replacement. The decay of tradi onal mber windows is most o en caused by moisture penetra on which can be easily prevented by regular checks and maintenance. Where rot has been detected within a frame it is important to iden fy and eliminate the source of the moisture and promote the drying out of the mber. Where possible the window should be repaired by removing the aff ected sec ons and splicing in new mber sec ons. This approach retains the historic fabric of the building and conserves the character by retaining the visual appearance.

It is essen al with the repair of sash windows that any repair ensures that the weight of the sash frame remains the same to allow the counter-balance mechanism to func on correctly. Both sash and casement windows should be repaired using tradi onal pu y. Glazing beads and modern compounds are not appropriate.

ReplacementReplacement will only be considered if the original or tradi onal windows are beyond repair. Like-for-like replacements must exactly match the design, detailing, propor ons, materials, fi nishes and method of opening of the exis ng window so that the special character of the building and the area is conserved. Jus fi ca on for complete replacement will be required. If modern or unsympathe c windows are to be replaced with a more sympathe c style then it is important that the detailing, propor ons and design are appropriate to that building.

Neighbouring buildings or historic photographs may provide clues as to the original style. Alterna vely Conserva on Sec on can assist in determining the appropriate window design.

Historic GlassSome historic windows may retain their original stained, crown or cylinder glass. This glass is of signifi cant interest for its age, rarity and also the fi nish which is detectable by the irregular surface which results in a distorted view. If a window is found to contain historic glass it should always be retained and reused wherever possible. Great care is needed to remove the glass and it should always be stored safely during renova on works. Replacement glass can be sourced from specialist companies or salvage yards. Hor cultural glass may also be considered suitable in some instances as it displays similar characteris cs to historic glass.

Iron Casements and leaded lightsHistoric leaded and metal frame casements are an increasing rarity. Wrexham contains many historic buildings which have metal framed windows and/or leaded lights as part of their original design which should not be lost. Whilst metal windows o en appear beyond repair, in most cases they can be retained and repaired successively and this should always be the fi rst op on. Common problems with metal windows include rust, distor on, failing of hinges and fi ngs and build-up of paint. Metal windows o en have a very fi ne profi le and frame and their aesthe c values, character and historic interest cannot be replicated in altera ve materials. Where repair is not an op on then like for like replacement should be undertaken. Extensive repair works and replacement of metal or leaded lights should only be carried out by a specialist.

What should be avoided?

The inser on of modern, factory made standard windows of all kinds, whether in plas c, galvanised steel, mber or aluminium is almost always damaging to the character and appearance of historic buildings and will rarely be accepted as an appropriate replacement to tradi onal windows in listed buildings or buildings within Conserva on Areas where planning permission is required as a result of an Ar cle 4(2) Direc on.

PVCu - There has been a progressive and damaging trend to introduce PVCu windows in historic proper es. PVCu is not a tradi onal building material and is unsuitable for historic buildings aff ec ng the appearance and the ven la on of the building. PVCu windows have a crude appearance lacking the fi ner detailing of tradi onal windows. The size of the frame is usually much larger than tradi onal openings making the PVCu window an obtrusive, obvious feature. The chunky appearance and shiny fi nish is completely out of character with historic buildings. PVCu windows are never acceptable on a listed building and rarely on buildings within Conserva on Areas.

Some companies are producing PVCu windows that aim to replicate a tradi onal mber window with mock wood – grain coloured fi nishes and tradi onal detailing such as sliding sashes and fl ush fi ng, side hung casements. The propor ons of these windows remain chunky however and their use in replacing mber windows within a Conserva on Area has yet to be supported where planning permission has been necessary. Where such windows are proposed to replace exis ng PVCu windows and off er an enhancement to the appearance of the building in terms of design and detail, they may be acceptable within a Conserva on Area.

Steel/Aluminium - Similar to PVCu windows, steel and aluminium have a modern appearance that is out of keeping with the tradi onal character and appearance of most historic buildings; some listed buildings have original steel windows where replacement in modern steel may be acceptable. Modern materials are o en be er suited to modern buildings.

Mass-produced modern mber windows - Factory produced mber windows are o en made of poor quality so wood which has a short life expectancy. Na ve hardwood is be er and more sustainable. Modern mber windows usually have standard detailing that has li le regard

to the subtle detailing of the original windows. Commonly they include modern fi nishes such as storm proofi ng and trickle vents which are not in keeping with the character of historic buildings and such details will not be accepted on replacement windows.

Standard Profi le Double Glazing - There is an increase in demand for double glazing in historic buildings to help improve the thermal quali es of the building. Standard double glazed unit are between 22 to 28 mm thick and are usually impossible to install within exis ng frames without signifi cantly altering the propor ons and profi le of the frame and glazing bars which generally need to be larger to accommodate the heavier and thicker glass. For this reason standard double glazing is not accepted in listed buildings and will be strongly resisted in buildings within Conserva on Areas where planning permission is required.

Specialist companies do exist that can supply slimmer profi le double glazed units have a narrower gap of air between the glass and can vary in depth from 10mm to 16mm. These slimmer profi les can help to be er replicate the original and tradi onal propor ons of the window than standard double glazed units and their use may be considered appropriate where they replace non-tradi onal and/or unsympathe c windows off ering an enhancement to the appearance of the building; and where there use within a Conserva on Area would not adversely aff ect the overall propor ons of the exis ng window nor the appearance of the building. Detailing however remains essen al and any replacement must respect the tradi onal propor ons, profi le and fi nish of windows appropriate to the building.

Historic Windows and Energy Conserva onImproving thermal insula on is a major priority for most home owners in terms of comfort,

economy environmental benefi ts. This is a common argument used to support the replacement and altera on of tradi onal and historic windows which are o en referred to as unsustainable. The reten on of historic windows is, in itself, a sustainable approach. Historic windows contain embodied energy, this is the energy used when the windows were originally made. Retaining them therefore preserves this embodied energy and negates the need to expend more energy on replacement windows, which will need to be cut, shaped and transported. When properly maintained, historic windows can last hundreds of years and many historic proper es within the County Borough retain their original windows.

PVCu double glazed window units are commonly inserted in place of

historic and tradi onal windows as a means of improving the thermal performance of a building. Whilst they require less maintenance they only have a limited lifespan and cannot be easily repaired with the whole unit o en requiring replacement when elements of the unit fail. PVCu is not biodegradable or easily recyclable and takes many hundreds of years to break down in landfi ll and is therefore not considered as environmentally friendly as tradi onal mber. Within historic proper es it has been es mated that 20% of heat is lost through the windows, much of it through the gaps around the window frames. The rest is lost through suspended and ven lated fl oors, open chimneys and roofs. Therefore replacing historic and tradi onal single-glazed windows with double glazed units cannot alone address heat loss.

Plant-on Glazing Bars – The use of plant-on glazing bars is not generally acceptable. Tradi onal glazing bars form an integral part of the frame forming the suppor ng structure. Plant-on glazing bars are modern interpreta ons of this detail and can detract from the character and appearance and can fail and become detached from the window frame a er a rela vely short period of me.

Modern Stained fi nishes - The use of modern stained fi nishes on exis ng or replacement mber windows is not a tradi onal or sympathe c fi nish and will not be accepted. Historically, most external joinery would have had a painted fi nish and this should be repeated on any replacement windows. Most paint manufacturers have a ‘heritage range’ of colours and further informa on on appropriate colours can be found at the contacts listed at the end of this document.

The thermal effi ciency and performance of windows can be improved using more appropriate, discreet and o en cheaper methods than replacement. These methods include:

Use of heavy, lined curtains, blinds or historic shu ers - This is perhaps the simplest method to improve effi ciency. Where historic shu ers exist they are an honest and eff ec ve way of reducing heat loss, draughts and noise.

Draught proofi ng or weather stripping - these can o en be fi ed into exis ng windows discreetly

allowing the character and appearance of the window to be retained whilst reducing heat loss and draughts.

Secondary glazing - Some historic windows can be fi ed with secondary glazing although this will depend on the size of the window recess and the window itself. When fi ng secondary glazing units care is needed to ensure that historic joinery, brick or stone work is not damaged, that the appearance of the window is not altered and that it will not impede a means of escape from the building. Listed building consent may be needed to install secondary

glazing into listed buildings and it is advisable to contact the Conserva on sec on to discuss any proposals in more detail.

When is permission required?

Listed Buildings - If you live in a listed building, that is a building recognised as having special architectural or historic interest, formal Listed Building Consent is required for any works which would aff ect the character, appearance and/or the special interest of the building. The following works to windows will require formal consent:

Replacement windows, where the new windows are of a diff erent style (Replacing inappropriate or modern windows in listed buildings with a more tradi onal and appropriate style s ll requires formal consent) Like for like replacement* Replacement of the window in a diff erent material Changes to glazing from single to double glazing and vice versa or re glazing which would result in the loss of historic glass Repain ng in a diff erent colour

*Like-for-like repairs and/or the replacement of windows in listed buildings may require Listed Building Consent dependent on the extent of the works involved

Conserva on Areas - Planning permission is not normally required to replace or make altera ons to windows on dwelling houses within Conserva on Areas. However some Conserva on Areas within the County Borough have stricter planning controls due to Ar cle 4(2) Direc ons which require a planning applica on to be submi ed for altera ons to windows that include changes to the detailing, style, materials, method of opening and fi nish insofar that the window(s) are visible from a highway, footway, waterway or open space.

Conserva on Areas subject to an Ar cle 4(2) direc on are: Bangor on Dee Cefn Mawr Chirk Fairy Road Gerald Street (Within Grosvenor Road Conserva on Area) Holt Overton Pontcysyllte Aqueduct and Canal Salisbury Park Rosse Ruabon inc Grenville Terrace

If you live in a Conserva on Area without an Ar cle (4)2 Direc on and do not require planning permission to replace or alter your windows, you are strongly encouraged to follow the advice given in this informa on sheet.

Replacement Windows and Building Regula onsReplacement window installa ons will not normally require building regula on approval providing the installa on company are FENSA registered. For further advice please contact the Council’s Building Control Team on 01978 298994.

Environment & Planning DepartmentWrexham County Borough Council16 Lord Street, Wrexham LL11 1ARTel: 01978 298994Email: planning@wrexham.gov.ukwww.wrexham.gov.uk/planning

Ins tute of Historic Building Conserva onJubilee House, High StreetTisbury, Wiltshire, SP3 6HATel:01747 871717Email:admin@ihbc.org.ukwww.ihbc.org.uk

Cadw: Welsh Historic MonumentsPlas Carew,Units 5/7 Cefn Coed,Parc Nantgarw, Cardiff CF15 7QQTel: 01443 336000Email: cadw@wales.gsi.gov.ukwww.cadw.wales.gov.uk

Royal Ins tute of Bri sh Architects (RIBA)66 Portland Place, London, W1B 1ADTel: 020 7580 5533Email: cas@inst.riba.orgwww.riba.org

The Society for the Protec on of Ancient Buildings37 Spital Square, London E1 6DYTel; 0207377 1644Email: info@spab.org.ukEmail: conserva on@rics.org.ukwww.spab.org.uk

Royal Ins tu on of Chartered Surveyors (RICS)Informa on Service12 Great George Street, LondonSW1P 3ADTel: 020 7222 7000www.rics.org.uk

The Georigan Group6 Fitzroy SquareLondon W1T 5DXTel: 020 7387 1720Email: info@georgiangroup.org.ukwww.georgiangroup.org.uk

Health & Safety Execu ve (HSE)Sheffi eld Informa on CentreBroad Lane, Sheffi eld, S3 7HQEmail:hseinforma onservices@natbrit.comwww.hse.gov.uk

The Victorian Society1 Priory GardensBedford Park, London W4 1TTTel: 020 8994 1019Email: admin@victorian-society.org.ukwww.victorian-society.org.uk

Historic England: Tradi onal Windows; their Care, Repair and Upgrading (Feb2017) available to view and download from h ps://www.historicengland.org.uk/images-books/publica ons/tradi onal-windows-care-repair-upgrading/

Cadw: Managing Change to Listed Buildings in Wales (May 2017) available to view and download from h p://cadw.gov.wales/historicenvironment/publica ons/

Cadw: Heritage Impact Assessment in Wales (May 2017) available to view and download from h p://cadw.gov.wales/historicenvironment/publica ons/

Cadw: Conserva on Principles for the Sustainable Management of the Historic Environment in Wales available to view and download from h p://cadw.gov.wales/historicenvironment/conserva on/conserva onprinciples/

Contacts and Further Informa on:

before a er