Wooden Windows & Doors for Britain's Heritage Homes
Our Accreditations
Sliding Sash Windows
Sash Window Upgrades & Restoration
Restore the original charm of your wooden sash windows while upgrading to heritage double glazing & English Heritage draught-proofing.
Box Sash Window Replacement
Traditionally made timber sash windows, crafted to meet conservation requirements and deliver modern efficiency.
Casement Sash Windows
Casement Sash Upgrade & Restoration
Preserve the character of your original timber windows while upgrading to heritage double glazing & discreet draught-proofing.
Casement Sash Window Replacement
Handcrafted to meet conservation requirements while delivering the benefits of modern performance & durability.
Front Doors & Rear Doors
Front Doors
Handmade to match original styles with heritage mouldings, glazing options, and high-security locking.
Rear & French Doors
Enhance your period property with our timber doors — combining traditional detailing with modern security and thermal performance.
Who We Are
Landmark Windows Co Ltd is a trusted family-run workshop, led by Steve and his sons, Tom and Ben, alongside a skilled team of joiners and craftspeople. With over 35 years of experience, we specialise in timber sash windows and doors for period and listed properties.
Known for our expertise in traditional joinery and heritage design, we’ve built a strong reputation across London’s growing conservation areas — delivering high-quality, conservation-grade joinery that blends original detailing with modern performance.
All of our products are made in-house, with full control from manufacture through to spray finishing and glazing — ensuring exceptional quality at every stage.
Frequently Asked Questions
Do you service both the Residential & Trade market?
Yes, we have dedicated team of surveyors working directly with our Installations Teams for Residential & Commercial installations.
Currently 80% of our production is dedicated in supplying sash windows & doors direct to trade & other window companies installing for there own Residential customers.
Do you manufacture in Accoya Wood & Hardwood?
Yes, we manufacture in both Accoya Wood & sustainably sourced Sapele Hardwood.
We never use softwood!
What guarantee do you offer on windows & doors?
Windows & doors come with a 10-year guarantee, plus 10-year insurance-backed cover via the Consumer Protection Association (CPA). We also provide a full aftercare service.
What is the lead time on windows & doors?
Manufacture only: 4–6 weeks. Manufacture & install: 6–8 weeks. Exact timings are confirmed with your quote.
Do windows & doors have to be fully finished & glazed?
No, we offer flexible options, including part-finished or unglazed, depending on your project needs.
For trade, we tailor supply based on your own workshop facilities.
Can you help with planning permission for listed buildings or conservation areas?
Yes, we provide detailed heritage planning reports & drawings to support listed building consent and conservation area applications.