Fountainbridge Window Renovations, Edinburgh: Sash and Case Windows

Timber sash and case windows, have been around for two or three hundred years and the operating principle remains unchanged today.

The very design of these windows allows the ingress of air in varying quantities depending on the external air pressure. Operating clearances allow the sliding sashes to operate smoothly, but the clearances also allow draughts.

The ingress of air can be virtually eliminated, except in exceptional weather circumstances, by the unobtrusive Sealglide Draught Proof System (see further details). This system, first designed several years ago, has been constantly updated with improved products and is recognised in the trade as the best available.

Restoration of sash and case windows is generally required for buildings of special interest such as Historic Buildings, Heritage Buildings, Listed Buildings and some Conservation Buildings. In these properties special mouldings such as astragals, sash stile mouldings, shapes and dimensions must be reproduced in exact minute detail and require much greater skill, and consequently a more expensive exercise, than normal renovation.

Renovation is slightly less onerous and involves a full check for timber decay, putty decay and other items such as ropes, weights, dimensional checks for proper operation, removal of external paints and re-painting, generally with primer, undercoat and gloss or other paints if appropriate (see further renovation details).

Thermally, a single-glazed sash and case window is very inefficient from two sources, the inherent draughty design and the inefficiency of single glass. The insulation factor of single glass is well known and has a U Value of 5.4. The U Value of double glazing depends on the construction of the double glazed unit - lower values indicating more efficient insulation. When the external temperature approaches O˚C and the ambient room temperature is around 20˚C, the warm air against a single glazing will cool and cause a down-draught exceeding two metres per second. Simply place the palm of your hand downwards facing the floor adjacent to the glass to experience the air movement, the back of the hand being more sensitive than the palm (see further detail on Slimlite Double Glazing).

Renovation is probably the most important factor to ensure long life of sash and case windows. The undernoted comprehensive check list will identify all the categories of remedial action necessary.

1	Check initially for proper operation and any evidence of decay.

2	Check the alignment and clearances between sashes and case.

3	Check the weight operation for passing clearance and correct balance.

4	Check the ropes for wear, size and dryness. Ropes have a limited life and unless they have been replaced very recently are always renewed. For this reason ropes are excluded from our ten year insurance backed guarantee.

5	Axle rope pulleys are checked on removal of the sashes and are either cleaned, oiled and serviced or replaced as necessary.

6	Replace missing or faulty putty where necessary to prevent water penetration.

7	Check the meeting rail snibs for proper closing of the meeting rails and simplex fittings for proper opening of the lower sash. Generally we replace these items with brass fittings and sash lifts which are fairly inexpensive. For instance new brass sash lifts cost £10.00 fitted. New brass ironmongery really enhances the window appearance. However where you wish the old fittings to be retained they can be cleaned at a cost of around £5.00 per piece.

8	Check all round for excessive paint build up particularly on the cases and remove, as necessary. Sand down the external faces of sashes and external cills and external areas of case and finish with one coat of primer.

9	Re-fit sashes, check for correct alignment and seating, check for correct movement and correct operation of the ironmongery.

10	All timber replacement repairs such as bottom cills are done with treated redwood and are given one coat of clear preservative and primer where required.

Note:

When the sashes are in a particularly bad condition it is sometimes preferable to have them completely
stripped by dipping them in a solution which removes all paint and most putties. The sashes are then
cleaned, smoothed, sanded, the tenon joints re-fixed cramped and re-puttied. We would only recommend
this stripping service as a last resort before considering new sash and case or sashes.


	Unit 7, Forth Ind Estate, Sealcarr St, Granton, Edinburgh, EH5 1RF
	Tel. 0131 551 2959 Fax. 0131 551 2947
	Free Phone: 0800 316 6031
	Email. fountainbridge@mail.com


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