KLIS SASH WINDOWS
LONDON TIMBER SPECIALISTS
ISLINGTON | LONDON
Bespoke timber sash windows for Islington’s Georgian and Victorian terraces. Draught-free, double glazed, and made to honour the proportions your street was designed around.
Islington has some of the finest Georgian and Victorian terrace stock in inner London — the squares of Barnsbury, the stucco-fronted streets of Canonbury, the brick rows around Highbury Fields. These are streets built with strong proportions and consistent character, and sash windows are integral to both. On terraces where uniformity is the point, the standard of any window work is immediately apparent.
Klis, Besi and the team handle every Islington job in person. No call centres, no subcontractors.
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Islington’s Georgian and Victorian terraces depend on consistency — one window out of step affects the whole street. We measure everything from your existing frames and replicate profiles, glazing bars and sash weights with enough precision that new windows read as original.
We measure everything from your existing frames and replicate profiles, glazing bars and sash weights with enough precision that new windows read as original.
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Islington has 42 conservation areas, and Article 4 Directions removing permitted development rights apply in 40 of them — one of the highest proportions of any London borough. Barnsbury, Canonbury and Highbury are among those most relevant to period residential properties. We’re familiar with Islington Council’s requirements and can advise on what applies to your property before you make any plans.
We’re familiar with Islington Council’s requirements and can advise on what applies to your property before you make any plans.
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Our own team handles everything — survey, manufacture, installation and finishing. No work goes elsewhere, and the standard holds across every job.
LONDON TRUSTS KLIS SASH WINDOWS FOR HONEST & ACCURATE ADVICE
We’ll assess your windows in person and give you a straight recommendation. No obligation, no upselling. Free home visit across London.
Bespoke timber sash windows built to your exact proportions and fitted precisely in period and contemporary homes.
Bespoke bay and box bay windows designed and fitted to suit your home’s proportions and style.
Modern sealed units fitted into traditional timber frames. More warmth, better noise reduction, lower energy costs.
Stop cold air, reduce heating bills, and eliminate rattles in the home without having to replace your existing windows.
Broken cords, rattling sashes, jammed frames, and more. We restore original timber windows to full working order.
Looking for high-quality, handcrafted timber windows only? We supply bespoke sash and bay windows to clients and trade.
Surface-level rot can be addressed, but once the core timber has softened, no repair holds for long. Wood that gives under pressure at the corners or sill means the frame has lost its structural value — replacement is the only permanent answer.
Islington's Georgian and Victorian homes lose a significant amount of heat through single-glazed sash windows. If you notice cold air at the frame, condensation on the glass, or traffic noise carrying through clearly, double glazing will deliver a genuine and lasting improvement.
Sashes that won't move, cords that have gone, frames that have shifted out of square — common issues in Islington's older stock. When a window can't open freely or seal properly, replacement is the more considered long-term choice.
We visit your Islington property, look at your windows on-site and provide a written quote. No pressure, no obligation, no middlemen.
Your windows are crafted to specification and fitted by our own team, keeping disruption to your household to a minimum.
Old frames removed and disposed of, the site left clean, every window checked before we leave. We're available if anything needs following up.
We install and repair timber sash windows throughout Islington and the surrounding area. Not sure if we cover your road? Get in touch and we’ll let you know.
Get in touch with Klis Sash Windows to arrange a free home visit and a no-obligation conversation about your sash window requirements.
No pressure tactics, no hard sell — just straightforward advice so you can make the right decision for your home.
Repair makes sense when the core frame is still sound — cord replacements, draught treatment, minor rot and rattles can all be handled without touching the whole window. Where the timber has failed structurally, or where you’re looking to move to double glazing, replacement becomes the right answer. We’ll tell you honestly which applies after looking at your windows in person, and we won’t suggest replacement when repair is the better option.
Yes. Islington’s Georgian and Victorian terraces have strong, consistent window proportions — getting them wrong is noticeable. We take all reference points from your existing windows and replicate profiles, glazing bar layouts, meeting rail positions and overall dimensions exactly, so replacements sit correctly within the elevation.
Yes. Every replacement we make is available with sealed double-glazed units in a traditional timber frame — improved thermal performance and better noise reduction without altering the period look. Triple glazing is also available, and worth considering for Islington properties on busier through-roads.
Yes. Islington has 42 conservation areas and Article 4 Directions covering 40 of them — among the most extensive restrictions of any London borough. This means planning permission is required for most external window work, including like-for-like replacements, across the vast majority of the borough’s period residential streets. Islington Council also has over 4,500 listed buildings. We know the borough’s requirements and can advise on what your property and street will need before you commit to anything.
For a standard job of two to four windows, on-site installation usually takes a day or two once the windows are ready. Larger projects are sequenced to limit exposure time at each opening. We’ll give you a clear programme at the survey stage and keep disruption as brief as possible.
We use sustainably sourced African Sapele hardwood — stable, durable, and well-matched to the UK climate. All timber is treated before installation. Repainted on a five to seven year cycle, a quality timber sash window is a long-term investment. We’ll go through the maintenance approach with you at handover.
Yes. Removal and disposal of old frames is part of the job — no additional charges. We protect surrounding surfaces throughout, clear everything before we leave, and check each window opens, closes and seals correctly before we go.
Cost depends on window count, individual sizes, glazing specification and any complexity around conservation area requirements or period matching. Fully installed replacement sash windows start from around £1,200 per window as a guide. A free home visit is the most reliable way to get an accurate number — we’ll assess your windows and produce a written quote with no commitment required.
