The size, shape, position and style of a property’s windows are hugely influential in defining its character – and making inappropriate changes can detract from a property’s charm and, along with it, its value.

Modern double glazing units offer superior energy efficiency and sound exclusion, but something is always lost when single glazed windows are replaced with double glazing.

If you can resist the pressures of modernity and are willing to undertake a few repairs, fit draft-proofing and occasionally repaint: you will be preserving your property’s original character.

Old windows are likely to be made from either timber or metal. Due to age you may find that they now fit poorly in their frames, resulting in drafts and rattles, and they could have damaged or broken sashes or glazing; but all of this can be repaired and improved to give comfort, energy efficiency and sound-proofing.

Repair or Replace?

Original window frames can always be repaired, even where there is extensive damage, such as wet or dry rot, but take a balanced view, comparing the cost of repair with the cost of replacing with sympathetically styled frames.

New replacement windows have their merits, but recapturing the fine detailing and charm of original windows is very difficult, as, with only a few exceptions, new windows have to be double glazed, and the inclusion of heavy double glazed units and frames substantial enough to carry them often results in compromises on design. Unfortunately, authentic replacements for period windows cost considerably more than standard replacements.

Restoring Sash Windows

Typical problems with sash windows include sashes that stick in the frame, broken cords, failure of joints, failure of putty, and damage to timber from rot, draughts, and rattling.

These problems typically arise from poor maintenance, and all can be repaired on a DIY basis or by a specialist. The cost of repair will usually be less than replacement, as good-quality replacement units range from £700 to £1,500. If your sash windows are curved, repair will almost certainly be the most cost-effective option, as bow-shaped windows are very expensive.

Conservationists claim that, providing there is at least 50% of the original timber remaining, a window should be repaired, not replaced. Most people will consider only small repairs, typically achieved by cutting out the section of damaged timber at least 50mm beyond the furthest point of decay, treating the remainder and splicing in a new piece of matching seasoned timber, followed by sanding, filling and painting. Alternatively, just the damaged components can be replaced. Draught and noise problems can be reduced by fitting the sashes with new seals, which will also ensure smoother operation. Where external noise is a problem, or superior energy efficiency is required, new double glazed sashes can be added, or secondary glazing fitted internally.

Window Furniture

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Don’t stop at curtains and blinds when dressing up your windows. The right window furniture is essential to ensure security with instant style and elegance. This monkey tail fastener from the Totali Solutions range, is ideally suited to cottages, listed buildings and period properties.

Repairing Leaded Lights

Leaded lights date back to the 15th century, when glass was expensive and could only be made in small fragments. Small pieces of blown glass were joined together using strips of lead to form rectangular or diamond patterns.

Part of the charm of these original windows is the way that light is reflected differently from each individual piece of glass. Modern copies are widely available, but tend to lack the individual character of originals.

Buildings with original 17th or 18th century leaded lights may be listed, meaning any damaged windows will have to be repaired or replaced on a like-for-like basis.

Leaded lights enjoyed a revival in the late 19th and early 20th century, so can also be found in Gothic Revival, Arts & Crafts, Cottage Orne, and Art Nouveau-style houses. Repairs to original leaded lights are relatively simple, but it is best left to a conservation specialist. If replacements are required, there are specialist manufacturers who produce authentic replicas.

Repairing Metal Windows

Metal-framed windows (cast iron, steel and bronze) are found on many period homes from the 18th and 19th centuries, mostly in sidehung casements, but also some sash windows; and also in houses from the early to mid 20th century, where steel windows were defining features of the Art Deco and International Modernist styles. They are also a feature of many houses with stone mullioned windows, such as those in the Cotswolds.

Common problems with metal-framed windows include distortion of the frame, buildup of paint, failed latches or hinges, failed glazing units, and rust. Problems such as rust and paint build-up can be repaired in situ, but for larger areas it may be easier to remove the frames and send them off for repair. Sections that are badly rusted can be replaced and new hinges or fittings welded on. If frames are to be removed, photograph them in situ beforehand and label them clearly.

Will I need approval?

Repairing windows on a like-for-like basis will not require planning permission or Building Regulations approval. In most cases, alternative replacement windows will not require planning permission either, unless the building is listed or subject to an Article 4 Directive (usually within a Conservation Area), in which case consent will be needed from the local authority for any demolition and alterations. The likelihood is that you will be encouraged by the conservation officer to repair if it is economically viable. Any replacements will have to be like-for-like. Replacement windows must comply with the energy-efficiency requirements of Part L (, which in most cases means double glazing will be necessary. The local authority can make an exception to the Building Regulations in the case of listed buildings. For those who insist on single glazing, it is possible to trade off the energy loss by making improvements elsewhere in the property.

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