A family business,
in its second generation.

Six over Six is a family business in its second generation, working on traditional box-sash timber windows across London and the Home Counties. The clue is in the name — six panes over six, the classic Georgian arrangement. It's also the kind of window we spend most of our time on: original joinery, often two hundred years old, still pulling its weight in a house that's been patched and re-painted by every generation since.

A well-built sash is one of the few period elements that can be restored almost indefinitely. The original Georgian and Victorian joiners specified slow-grown softwood — pine, deal, occasionally oak — that, properly maintained, outlasts the masonry around it. We've replaced cords on windows fitted in 1820 that still ran on their original pulleys. The lead weights inside the boxes were unchanged from the day the building was finished.

How we approach the work

Every job starts with a free survey. We come to the property, photograph each window, and write a quotation — itemised by window, by line of work, no upsells, no chasing. From there, the same craftspeople who quoted the job are the ones who do it. That's why we cap the size of the team and the geographic radius we work in: it keeps the work the work, and the people the people.

On site, the principle is repair before replace. Original frames, glazing bars and ironmongery stay wherever they can — splice repairs for rot, new cords and pulleys for mechanical wear, period-appropriate hardware sourced from specialist heritage suppliers where pieces are missing. Only what's failed gets replaced; what's tired gets serviced.

Modern glass in period frames

What changed in the last decade is vacuum-insulating glass — two thin panes separated by a 0.1mm vacuum gap, sealed at the edges. The whole unit is around 6mm thick, lighter than a single-glazed sash, and slots into the original rebate with minor frame adjustment. U-values come out at 0.7–1.1 W/m²K, in line with new-build standards. The glazing bars stay. The sash horns stay. From the street, the building looks the same. From the inside, it stops being cold to the touch.

Conservation, paperwork, planning

For listed buildings and conservation areas, the conservation officer is the audience as much as the homeowner. The starting position is always retention: the original window stays unless it's structurally beyond economic repair. We've worked with conservation officers across Cambridgeshire, Buckinghamshire and Hertfordshire, and we handle the pre-application enquiry as part of the job. Most consents are a question of how, not whether.

The frame stays. The glazing bars stay. The line of the window stays. What changes is the performance.

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