Contact us on 07710 096553 if you are looking for a sash and case window restoration company that serves Stirling, Dunblane, Bridge of Allan and the Central Scotland area. We have vast experience in restoration work to timber sash and case windows to Listed Buildings in the Outstanding Conservation areas of the Kings Park Stirling, Dunblane and Bridge of Allan.
We strictly follow this guidance issued by Historic Environment Scotland.
Below is very useful advice on the restoration work of timber box sash and case windows which we have taken from the link above on from Historic Environment Scotland.
Sash and Case Windows Restoration
The appearance of a fascade, and consequently of the building of which it forms a part, is greatly affected by the number, size and disposition of openings contained within it, and by the manner in which these openings are detailed.
Windows are therefore an important element in the design of any building and contribute substantially to a building’s character. In order to protect the appearance of such buildings, methods of repair and any proposals to carry out work that will alter the style, detailing, materials or method of operation of the windows require very careful consideration.
Evidence from surviving examples indicates that wellmade and maintained timber sash and case windows are easily capable of providing well over one hundred years of serviceable life. This durability can be extended by often quite straightforward repairs. By contrast modern window replacements are often made from substitute or inferior materials and are usually incapable of being repaired.
Where sash and case windows are damaged or decayed, or where building owners wish to improve the performance of windows to meet modern standards, there is often pressure for their replacement with new windows.
This frequently results in the new work having a different design or altered details, with resultant changes in the appearance and character of the windows, and with a consequent reduction in the historic value of the building of which they are a part.
Often these decisions are taken on the misunderstanding that traditional sash and case windows are not capable of being repaired, or of meeting current performance standards.
Historic Environment Scotland’s Guide for Practitioners sets out to demonstrate that it is possible to carry out successful repairs to windows that maintain and improve their performance, using traditional techniques and craft skills. Their guidance summarises current performance standards for windows, and demonstrates possible methods of achieving these standards in sash and case windows, while retaining the original materials, detailing and design.
By careful and thorough repair, correctly specified and carried out by suitably skilled contractors, existing windows can be made to meet acceptable performance standards, either alone or by additional upgrading, without significant loss of original material.
Where this is not feasible, more extensive alteration or additions can be considered. Exceptionally, new sash and case windows can be manufactured that match the original design but with improved performance.
The ‘T-shaped’ section that formed the glass check on the exterior, see figure 10 below. All early Scottish sashes have ovolo and fillet glazing bars jointed with mitred mouldings. The operable lower sash was usually counterbalanced by cast lead weights, suspended on sash cord from timber or brass pulleys.
The cased frame was not used in all early windows; solid-framed sashes were held open with a catch attached to the sash stile. The timber of choice was oak, preferably imported from Baltic countries, although native oak was widely used. The less important parts of the cased frame, the backs, internal linings and facings, were sometimes made in deal (fir or pine).
Many well-made original timber sash and case windows will perform satisfactorily, with the correct degree of maintenance, repair and modification. The performance of windows can be evaluated by the following criteria: weather resistance (air leakage, water penetration and strength) thermal performance sound insulation safety, security and convenience costs (lifetime cost-in-use).
An early nineteenth-century Scottish fashion was for the adaptation of the sash glazing pattern to imitate that In the eighteenth century when the sashes were unequal of the French window. In order to lessen the visual in size the top sash was normally taller, but from the disparity between French casements and sash windows early nineteenth century pattern this was reversed the vertical meeting stiles of the French window, see inmage below.
When plate glass became more affordable in the imitated in a single piece of timber, complete with middle of the nineteenth century it was sensible to have thicker profile and flush bullnose mouldings. This a lighter top sash, to lessen stress on the joints of the resulted in a sash of two larger (and usually squarer) meeting rail. The plate glass window often has one panes of glass wide, characterised by this thick central vertical or horizontal glazing bar, which gave the line.
The predominance of the sash and case window in Stirlings listed buildings, for at least two hundred and fifty years since its development, is testimony to its suitability for our climate and in providing adequate levels of convenience and comfort for building owners and occupants. Sash windows have developed to accommodate changes in taste and other technical requirements placed on their performance. Their relatively simple construction has proved to be durable, allowing them to be maintained and repaired throughout the period, and many early examples survive in working order.
There are no inherent defects in the design of the sash and case window. The basic construction has remained the same for over 300 years. That some of the earliest sash windows remain in use today is evidence of their potential durability given appropriate maintenance. The historic value and constructional details of original windows often form an important part of the surviving fabric of a building. Therefore whenever possible they should be restored rather than replaced.
Contact us now on 07710 096553 if you need some restoration work done to your timber sash and case windows.