Golden Ratio Windows: Expert Sash Window & Door Services in London
Time-served specialists providing heritage-grade restoration, repair, and bespoke joinery solutions.
Heritage Craftsmanship
Faithfully replicating original features in our London-based workshop using traditional joinery methods and preservative-treated timber.
Modern Efficiency
Our high-performance double-glazing uses 4mm glass panes with a 6mm cavity to drastically reduce heat loss and lower energy bills.
Guaranteed Quality
All products are covered by a 10-year transferable guarantee with optional insurance backing for total peace of mind.
Additional Services
Alongside our specialist sash window and door services, we also offer a range of bespoke carpentry and glazing solutions tailored to residential and commercial projects across London.
Coffee Shop Bar Fit-Outs
Bespoke coffee shop counters and bar installations, designed and built to suit your space and brand.
Shop Fronts
Custom shop front design, manufacture, and installation to enhance the appearance and security of your business.
Stained Glass
Traditional and decorative stained glass design, repair, and installation services.
Roof Light Glass Installation
Installation of high-quality roof lights to maximise natural light and improve interior spaces.
Bespoke Carpentry
Professional custom carpentry services, including made-to-measure joinery and interior woodwork.
Our 5-Step Restoration Process
Bespoke Survey
We assess timber health and heritage compliance status.
Precision Repair
Splicing high-performance Accoya® timber to eliminate rot.
Glazing Upgrade
Integration of Slimline or FINEO vacuum glazing.
Draught Proofing
Installing discrete brush strips for a rattle-free finish.
Final Finish
A professional spray or hand-paint for weather protection.
Specialist Joinery Across London Boroughs
Timeless Character, Modern Function
Sash windows are the "eyes" of London’s historic buildings. Our specialized repair and restoration services ensure that your home maintains its 19th-century charm while benefiting from 21st-century thermal performance.
Energy-Efficient Living
We eliminate draughts, reduce noise pollution, and ensure smooth operation to keep your London property warm and quiet, adding significant value to your heritage asset.
Trustworthy & Qualified Installation
Our craftsmen are CSCS qualified and adhere to CITB Health and Safety standards. We treat every home with care and respect, ensuring work areas are kept clean, tidy, and safe while remaining flexible to your lifestyle.