anatomy of a window lintel architrave inner staff bead top rail lintel upper sash glazing bar meeting rails horn pane lower sash reveal

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1 windows introduction Windows make a vital contribution to the character and appearance of historic buildings.the insertion of modern windows can completely ruin the look of a traditional building and considerably reduce its market value. Consent is needed from the City Council to install new windows at the front and rear of Listed Buildings and buildings affected by Article 4 Directions in the Avenham, Fishergate Hill and St. Ignatius Square Conservation Areas. If you don t know if your building is affected by such regulations ring the City Council on It is the policy of the City Council, in line with Government circulars, to refuse consent to install UPVC or metal windows or to replace vertical sliding sash windows with top hinged casements or dummy sashes. This guidance should be read in conjunction with Preston Local Plan Policy C6 (Alteration of Listed Buildings). 7

2 anatomy of a window lintel horn upper sash lintel architrave inner staff bead top rail glazing bar meeting rails pane reveal lower sash bottom rail inner staff bead internal cill cill stone subcill 8

3 types of traditional window commonly seen in Avenham commonly seen in Ashton 12 pane Georgian 16 pane Georgian 2 pane sliding 4 pane sliding sash no horns sash no horns sash with horns sash with horns common window types in Preston The three main types of window found in historic buildings are: 1) Vertical Sliding Sash This form of window opening was introduced around 1670 and was the original type of window in the majority of buildings in the urban area of Preston built between 1700 and It has hollow boxed sides and two opening lights which slide up and down. Eighteenth and early nineteenth century windows had glazing bars, mid nineteenth century windows were usually divided by a single vertical bar, while later nineteenth century windows were generally plain. Before 1850 sashes were made without horns (see diagram). So windows with glazing bars and small panels should be made without horns. 2) Hinged Casement This type of window has been used for a much longer period than the sliding sash and is commonly found in the rural area, particularly where windows are divided by stone mullions into a series of small openings. It has side hinges, opens outward and is often used together with fixed windows. 3) Horizontal sliding or Yorkshire sash This is a less common type of window which was used in the nineteenth century for small window openings in rural properties and service rooms in urban houses. One half of the window is usually fixed and the other half slides behind it on a horizontal wooden track.these windows usually had glazing bars. 9

4 selection of glazing bars astragal and hollow lamb s tongue bead and hollow quadrant sash ovolo with appropriate pin and putty for fixing glass glazing bars to avoid upvc glazing strip sandwiched between glass crude thick modern glazing bar inappropriate timber beading for fixing glass repairing windows Traditional sash or casement windows should be repaired whenever possible. A competent joiner will be able to replace minor sections of rotted timber such as cills or glazing bars in a fundamentally sound window.a joiner is also able to overhaul traditional sashes by removing surplus paint and replacing broken sash cords. The overhaul and repair of an old sash window is preferable to its complete replacement because generally older timber is of a far superior quality to modern timber and keeping the original features maintains both the historic and market values of the building. Some 18th and early 19th century windows still have their original Crown or Cylinder glass. This contains many minor flaws and catches the light in an interesting way, unlike modern plate glass. Original glass should always be kept and re-used if the window is beyond repair. 10

5 insulation The replacement of traditional sliding sash or casement windows is not a cost effective way of improving insulation. Draught strips and perimeter seals can be inserted into traditional windows by a competent joiner. Heat loss can be reduced by secondary glazing or very economically by clipping perspex sheets behind the windows. Heavy curtains or wooden shutters can be as effective as double glazing for reducing heat loss. replacement windows do s Where windows are beyond repair replacements should match the originals exactly. If you are unsure about the style of the originals look at identical buildings in the street, try to find an old photograph or ask the City Council s Conservation Officer for advice. Use a traditional weight, cord and pulley system for sash windows rather than spiral balances which are less reliable. Use paint to preserve and decorate new windows. Microporous paint allows the timber to breathe and is very easy to use and maintain. 11

6 replacement windows don ts widening of window opening and installation of inappropriate casement windows upvc with glazing bars sandwiched between panes of glass no reveal or depth to frame top hung casement window heavy glazing bars to contain double glazing windows to avoid in historic buildings Don t enlarge or partly fill in the original openings or remove original features such as external mouldings or internal shutters. Avoid using UPVC or aluminium windows as they can completely spoil the appearance of a historic building and can cosiderably reduce its market value. Recent tests have shown that properly treated timber windows have a longer life expectancy and are more economical to install. Avoid top hung or dummy sashes.these are poor imitations of traditional features and are easily detected as fakes, particularly when open. Avoid fixing the glazing into traditional windows using wooden beading.this thickens the dimensions of the frames and glazing bars and makes the windows look visually very heavy. Avoid staining timber windows.this type of finish was never used on traditional softwood windows and is therefore out of keeping with the appearance of historic buildings. Remember: If you need any advice on the repair or replacement of doors and windows in historic buildings please telephone Preston

7 Preston City Council Planning Department Environmental Services Directorate Lancastria House Lancaster Road Preston PR1 2RH