We are sash window specialists – they are the only product we make. As experts in our field, we’re alarmed when window installers and double glazing companies show little interest in the aesthetics of the homes in which they fit windows.

You’ve probably come across plenty of properties fitted with inappropriate windows. We've found that working with authorities and taking time to listen to their issues, has enabled us to produce PVC-U sash windows, which planning inspectors say, “enhance and improve” sensitive areas, “protecting conservation areas”.

Elegant sash windows from Masterframe


PVC-U tends to have larger sight lines than aluminium and steel but very similar proportions to Victorian sash windows. By far the biggest issue is the use of inappropriate designs. In order to cut costs, installers often leave the existing box frame in-situ, replacing just the broken or rotten sashes. This doubles the bulk of replacement windows. 

In an effort to fit windows quickly, they either “insert” casements into the old frame or install new windows on the outside front skin of brickwork. This cost cutting increases visible plastic sight lines, reduces natural daylight and significantly reduces ventilation and escape options in an emergency. They also ruin a property’s character and reduce its value.

We cannot control how windows are fitted, but you can insist that replacements are installed correctly. Our guidelines can help you – if you require names of our recommended installers who we trust to follow these guidelines, please contact us.


When conservation officers and planners take a close look at our products, they’re often surprised by the components we use:

  • wood white foil instead of shiny white plastic
  • Timberweld® butt-jointed construction
  • continuous horns over plastic bolt on extras
  • real-feel, three dimensional plant on Georgian bars to create shadow lines, rather than artificial, two-dimensional canes between glass.

As specialists, we're able to produce just about any sash window feature. All we ask is that you give us a detailed specification so we can build each window to your precise requirements. We've produced a Buyer’s Guide to assist the selection process, along with our Glossary of Terms.


All our products are BBA approved and manufactured to ISO quality standards. All our products are CE marked, A, B or C-rated, Energy Efficient and come Secured by Design – the Police preferred programme when requested.

And when planning inspectors say that your windows “resemble timber originals even at close quarters” then you know you are getting it right. We'd be delighted to discuss sash windows with you in detail, so you can see first-hand just how closely they match original sash windows.

Testimonial Michael Hagan

Aztec Windows (Coventry) Ltd, Coventry

“Exceeded our expectations, far superior quality and exemplary service!”

Become a preferred Bygone installer

Can you demonstrate the same care and attention to installation as we have to our products?

Apply to be an installer

Call Jack Sellick on 01376 510410 to request our informative Conservation Guide.



Learn why you get better windows because of these

  • BBA logo
  • ISO logo grey
  • Secured by design logo grey
  • BFRC logo grey
  • Energy Trust logo Grey
<h3>Setting standards, safeguarding interests</h3>
<p>Masterframe have been GGF members since the mid 90s. Our MD has served on the GGF main board and chaired the Home Improvement Executive, FENSA and the BFRC. Membership gives you greater protection on a number of levels.</p>
  • DGC logo grey
  • CE logo grey
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