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At Sash Restoration Belfast we manufacture traditional sash and casement windows in our sash window workshop in Londonderry. Everything is made in exactly the same style, but with discreet improvements on the originals, with better quality ironmongery, draught proofing system being integrated as standard and the option to upgrade to double glazing or slimline double glazing.


With double glazed sash and casement windows we provide a putty finish externally so the windows look exactly the same as the original. Usually all new sash windows are glazed with 24mm double-glazed low-emissivity glass to comply with the thermal requirements demanded by current building regulations. Occasionally the local planning authority will insist that new windows are single glazed to maintain the authenticity of the façade of a listed building – this will over-ride the demands of the building regulations. We make both single glazed and double glazed windows in any size or style. Our sash windows are constructed using the traditional haunched mortise and tenon joints.  This gives the window far more strength than those favoured by the mass produced market across the EU.  Our windows are then finished off by hand. This attention to detail makes a huge difference to the quality of the end product, and ensures your sash windows will last far longer. 


Our replacement sash windows are:

  • All new windows are made from joinery grade softwood; however we also supply BC pine and mahogany windows

  • All new glass single and double glazed is fitted to comply with current building regulations. All single glazed replacement sashes will be glazed with 4mm glass, clear or patterned. Double glazed units will be either 16mm (4.8.4) or 24mm (4.16.4) depending on the thickness of new windows and both come gas filled. The u-value of the 16mm units are 1.7 W/m2K. The U-value of the 24mm units are 1.2 W/m2K

  • Supplied with all necessary window ironmongery 

  • Hand painted (never sprayed) by our painters onsite

Our replacement casement windows are:

The casement windows we supply have the latest locking systems, with a wrap-around roller locking system used for all opening sashes. Our casement windows are designed to have the traditional appearance of hardwood, blending modern technology with traditional joinery methods. Choose from a range of Idigbo, Sapele or Oak stains or opaque colours.

Our casement windows have twin gaskets for maximum protection against the weather, which lowers the heat loss through the frame and the casement. The casements can open with either our standard handles or with a traditional range of decorative handles available on request. We can incorporate traditional monkey tail handles or bulb end handles, in a range of colours to compliment your design and colour of casement window.

All the windows we supply are manufactured to high standards with specifications to match, generic specifications are below (specification relative to design).

  • Flush or Stormproof (over-rebated) window systems available

  • Wrap-around, multi point espagnolette locking system as standard

  • Top or side opening sashes

  • Dummy (non-opening) sashes or direct-glazed sections available

  • Option of increasing component thicknesses in order to give equal sight-lines with adjacent doors etc

  • Arched or swept heads available

  • Windows can be incorporated into bays, conservatories and orangeries

  • Range of hinge options available, including approx. 90° opening for fire escape windows, child restriction for safety, “easy clean” mechanism, or combinations of these (depends on window size and configuration)

  • Very large and very small opening casements achievable, with a wider range of sizes available than many of our competitors

  • Colour-matched internal window boards available

Contact us today to discuss your requirements with one of our helpful and friendly team members. They are always on hand to answer any questions you may have and provide honest and impartial advice.​ Or for further information please contact us at: or call our head office on: 0207-1646305.

Sash Restoration Belfast Team

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