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Welcome to the future of glass technology with our vacuum glazed windows and doors.


a breakthrough for
listed buildings:

Vacuum glass has arrived, and it's revolutionising the way we approach insulation and preservation.

From initial consultation and survey, planning approval, manufacture, installation and final making good, we offer specialist services for listed buildings which are unique to each project. If you are considering altering the windows or doors of a listed building, it is essential to consult with experienced experts. For Sashed customers we offer a turn-key planning service, and we NEVER out-source planning applications to a third party; all planning applications and managed in-house by our team of directors.

See this page for more details of our planning services.

We can help with upgrading and windows and doors for listed buildings

If you live in a listed building you will need planning permission and listed building consent to change your windows and doors, this includes re-glazing of existing frames. Historically, planning permission for replacement windows and doors with double-glazing have mainly been refused. Vacuum glass offers a solution that will usually gain permission for most listed buildings.

Our ultra-thin Heritage Range with vacuum glass makes the perfect solution for your heritage and conservation projects. Our Heritage Range looks like single glazed windows but have all the benefits of double glazing and more. Ultra-thin profiles make vacuum glass perfect for retaining the aesthetics of single glazed heritage buildings, there is no internal double glazing spacer bar, and no visual disturbance from the double reflection associated with traditional double glazing. Vacuum insulated glass seamlessly mimics the appearance of single glazing, making it an ideal solution for listed buildings and conservation areas.

Our vacuum glazed windows are graining approval by Planning and Conservation Officers across London and the South East of England."

Bringing 21st century technology
to heritage buildings

There is a common misconception that replacing glazing in a listed building with vacuum glass doesn’t require planning permission. In our opinion, this notion is a bit of a stretch. While new glazing of similar thickness to the original glass can be installed, fitting vacuum glazing is a different matter. Planning permission is necessary due to the variance in thickness and the use of modern float glass.

It's also a misconception that you can effortlessly replace the glass in an old period sash designed for single glazing with vacuum glass. This approach would require substantial modifications to the old sash to accommodate vacuum glass, often making it financially impractical and leading to a structurally weakened, modified sash.

Depending on your specific building, condition of your existing windows, and your local authority’s planning policy it may be possible to gain planning permission for complete new windows and or doors using our Heritage Range with vacuum glass. The majority of inner London local authorities will not grant permission for ‘complete’ new windows (fames and sashes) but will grant listed building consent and planning remission to retain your existing frames and to retrofit or replace the sashes containing vacuum glass.

How is Vacuum Glass retrofitted into existing windows by replacing the sashes?

Step 1:

Remove existing single glazed sashes from the sash box (frame)

Repair any rot or damage to the sash box

Overhaul sash box to accommodate new sashes

Step 2:

Fit new sash pulleys

Replace old sash cords with new, replace weights and re-balance for the new sashes

Install new sashes into the sash box

Step 3:

Draft proof with specialist weatherproofing

high-performance brushes & seals

Decorate and paint sash box
Fit new suite of ironmongery

Compare Vacuum Glass with traditional glazing

Exceptional thermal efficiencies make vacuum glass 14 times more efficient than single glazing and twice as efficient as the average triple-glazed unit.

Compared to single glazing, vacuum glass provides a 35% reduction in noise levels, surpassing double or triple glazing by 20%. Longer service life than double glazing: LandVac comes with a 15-year guarantee, exceeding the standard 10-year guarantee for double glazing and the 5-year guarantee for slimline alternatives.

Ultra-thin 8.3mm profile ensures compatibility with slim timber profiles, preserving the original historic aesthetic that is not achievable with thicker double glazing.

Better light transmission: Vacuum glass allows more light into your property compared to double and triple glazing, as it has higher light transmission values. Double and triple glazing may absorb or reflect some light, reducing overall transmission.

50% lighter than triple glazing, providing both structural and practical advantages.

Vacuum glass isa low carbon product to manufacture with no noble gasses inside.

Energy Loss
Comparison in U-Values

Get a quote or make an enquiry

At Sashed we have a extensive experience in creating windows and doors for listed buildings, the majority of our projects are for London’s heritage housing stock. We are able to advise and guide you through the process, and provide you with beautiful bespoke windows and doors that will gain listed building consent.

I DO NOT live in a conservation areaI live in conservation areaI live in a listed buildingI'm unsure

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