Bay window restoration and rebuild services

London Stonemasonry have restored and replaced hundreds of bay windows over the years. We offer the full package. We repair, restore and replace stonework to the highest level of finish and craftsmanship.

Find out more about our bay window services on this page:

We work on bay and stone mullion windows from all periods, including: Georgian, Victorian, and Edwardian. Our goal is to enhance and add value to your home or business premises.

We always give a complete breakdown of all aspects of the works within our quotation so you can see exactly what we are proposing. We will also provide you with a full methodology, so you can understand how we are undertaking the works.

A bay window restoration by London Stonemasonry

Pictured: London Stonemasonry transformed the front of this terraced house in Stratford, London.  We replaced UPVC windows with a new hand-carved Victorian-style bay window, repointed brickwork, created a new lead roof for the bay, laid paving and built a new front wall.

 

“In the Georgian and Victorian eras, it was very common for new home buyers to have input into the design of their houses as they were being built. If you keep a keen eye out, you can still spot how designs of bay windows and entrance ways can change on the same terraced road.

“We offer bespoke personalised designs for your bay window. While retaining all period correct design and ratios, your window stonework can reflect your style and individuality.”

Will Horn, Director, London Stonemasonry

Stone bay window repair

London Stonemasonry’s experts are highly skilled in bay window repair. We offer a full service; repair, restoration, replacement and redecoration.

We start every bay window project by diagnosing the real causes of damage. Common issues we are asked to repair, include: leaning or cracked masonry, spalled or water-holding cills, rust-jacked mullions and lintels, cement “patch” repairs, and leaking bay roofs or flashings that lead to damp and sticking windows inside.

Where possible, we keep and repair the original stone with gentle cleaning, lime re-pointing and small indents or plastic repairs. Where stones are too far gone, we cut out only the failed sections and piece in new, matching units securely fixed with stainless steel cramps and dowels.

On severely distorted or unsafe bays, we carefully prop, number and dismantle the structure, rebuild any defective backing brickwork, then reconstruct the bay using a blend of salvaged and new stone, while also upgrading weathering and structure with improved cill falls and drips, new lead trays and bay roofs, crack-stitching, hidden lintels and ties back to the main façade, often in coordination with new or refurbished windows so the finished bay is both authentic in appearance and robust for decades to come.

Bay window restoration in Bath stone by London Stonemasonry

Pictured: A Victorian stone bay window created by London Stonemasonry. Hatchard Road, Archway, London, N19

Bay window replacement

Stone bay window replacement is required when a bay is too cracked, leaning or heavily patched for repair alone to keep it safe, weather-tight and true to the character of your home.

On many Georgian, Victorian and Edwardian houses in London and the South East, we replace failed bays by first surveying every cill, jamb, mullion, head and cornice, then designing a new stone bay as a complete structural and weathering system, with proper foundations or bearing, hidden lintels and stainless steel ties, correctly detailed cills and a sound bay roof and lead tray.

Wherever possible we salvage usable stones and blend them with new units carved to match the original profiles, so the replacement bay sits plumb with the façade and works perfectly with new or refurbished windows.

For homeowners and builders, this approach restores lost detail, improves comfort and protects long-term value; if your bay is visibly moving, cracking or letting in water, we can assess it and deliver a full stone bay window replacement service – survey, design, supply and installation – so the front of your house looks right and performs reliably for decades.

Bay window restoration in Bath stone by London Stonemasonry

Pictured: A Grade 2 listed property’s upper bay window on Manor Road, Stoke Newington, Hackney, replaced by the London Stonemasonry team. Find out more.

Bay window design

Stone bay window design is an essential element of our bay repair, rebuild and replacement services.

On London’s Georgian, Victorian and Edwardian homes we start with the architecture; the proportions of the elevation, existing brick and stonework, and the period detailing – then design bays with the right projection, cill lines, mullion spacing and profiles for that style.

We undertake all design aspects. From detailing and precisely measuring neighbours’ windows to produce an exact copy or creating new, bespoke, designs and drawings.

We treat the bay as an engineered system: cills and sub-cills that shed water properly, mullions, jambs and heads that carry loads safely, and bay roofs and flashings that protect the structure beneath.

Whether we are reinstating a lost bay in stone, designing a new bay for an extension, or tying bay work into new windows and insulation, our aim is to create a stone bay window design that looks authentic on day one, performs reliably in bad weather and adds lasting value to the property.

Bay window restoration in Bath stone by London Stonemasonry

Pictured: A bay window restoration in Bath stone by London Stonemasonry

Victorian bay window construction

Victorian stone bay windows are some of the most beautiful, and most vulnerable, parts of a London house. When they begin to crack, lean or shed pieces of stone, you need more than a builder, you need a team that understands how those bays were designed, how they carry the weight of the façade, and how to rebuild them without losing any of their character.

At London Stonemasonry, Victorian bay work is not an occasional add-on; it is one of our core specialisms. We combine workshop-trained stonemasons, careful structural thinking and conservation-led methods to diagnose the real cause of the damage, then repair, rebuild or replace the bay in a way that is both safe and faithful to the original design.

We can repair, hand carve and then install every stone element of the window, including: corbels, floral capitals, jamb and mullion bases, lintels and sills. We also repair and build bay window brickwork and roofs.

For a list of some of the Victorian bay window elements that we repair, restore and replace, expand the sections below:

A double bay window rebuild by London Stonemasonry

Pictured: A Victorian double bay window rebuild in Ivanhoe Road, Peckham, SE5, by London Stonemasonry

  • Angular returns and canted faces – The three-sided geometry of a canted bay demands precise setting-out. We specialise in templating and cutting the angled stones so joints are tight, lines are clean and the bay reads as a crisp, three-dimensional feature rather than a muddled projection.
  • Backing brickwork and internal masonry – Behind the stone face sits a leaf of brickwork carrying floor and wall loads. Our teams open up carefully, repair or rebuild backing brickwork where needed, and re-tie it to the new or repaired stone so the complete bay works as a single, stable structure.
  • Bay roofs, lead trays and flashings – Many stone problems start with a leaking bay roof. We rebuild bay roofs with proper falls, renew lead trays and flashings, and coordinate detailing with the stone below, so water is managed correctly instead of tracking into joints and causing further decay.
  • Brackets, corbels and supporting features – Oriel and upper-storey bays often rely on carved brackets or corbels. We can assess their loading, carve like-for-like replacements where units are failing, and discreetly reinforce them so they still look delicate but behave like the robust supports they need to be.
  • Copings, parapets and top stones – The uppermost stones are exposed to the worst of the weather. We replace cracked or loose copings, improve throatings and drips, and tie parapets back safely, reducing the risk of falling masonry and future water ingress into the bay structure.
  • Cornices, string courses and horizontal mouldings – These bands tie the bay back into the façade and help shed water. We accurately reproduce Victorian profiles in matching stone, running them cleanly across the bay and main wall so the elevation reads as one continuous, well-detailed composition.
  • Foundations and plinths – Victorian bays usually sit on their own foundations or thickened plinths. We understand how these interact with the main façade, so when a bay is leaning or settling we can stabilise or rebuild the base properly, rather than just patching cracks higher up.
  • Interior reveals, cills and finishes – Internally, the stone and brick geometry determines the shape of plaster reveals, timber boards and shutters. When we repair or rebuild a bay we take care to keep these lines true, making good plaster and joinery so the inside reads as well as the outside.

  • Interfaces with windows and glazing – The meeting line between stone and sash or casement frames is a frequent weak point. We form square, true openings, coordinate with window specialists, and use appropriate pointing and seals so frames sit correctly, operate smoothly and remain weather-tight.
  • Jambs (side stones) – Jambs frame the outer edges of the bay and pick up loads from above. We can carry out fine indent repairs where damage is local, or cut and replace full jambs, toothing new stone back into the brickwork so the bay is once again structurally sound and visually consistent.
  • Joints and pointing (lime mortars) – Hard cement pointing is a common cause of stone decay. We rake out inappropriate mortars and repoint with breathable lime mixes, matched in colour and profile, so moisture can escape and new stone or repaired units weather naturally with the original fabric.
  • Mullions (vertical dividers) – Mullions act as slender stone columns between window lights. We know how to repair hairline cracks, reinforce overstressed mullions with stainless dowels, or replace failed mullions entirely, all while matching original profiles so the glazing sits square and secure.
  • Overall structural tying and stability – Above all, a Victorian bay must work with the main façade, not pull away from it. We use modern, discreet stainless steel ties, crack-stitching and, where necessary, improved bearing at floor level to tie the bay back into the building frame, combining traditional appearance with reliable modern performance.
  • Rustication, mouldings and decorative carving – Victorian bays often carry rusticated blocks, bold mouldings and carved capitals. Our workshop can copy original details in matching stone, replacing lost or eroded work so your bay regains its character without resorting to crude concrete or resin patches.
  • Stone bay window cills and sub-cills – Cills are shaped to shed water with a fall and a throating. We routinely replace cupped, spalled or cracked cills with accurately profiled new stone, ensuring correct falls and drips so water is thrown clear of the wall and you are not paying twice for the same problem.
  • Window heads, arches and lintels – Whether your bay has straight, cambered or arched heads, they are key structural elements. We can replace failed stones, introduce hidden steel lintels where appropriate and rebuild brick relieving arches, ensuring the brickwork above is properly supported for the long term.

How much does a stone bay window cost?

Every bay window is different, so each project is priced individually.

We’ve put together a page of specific examples to give you a guide to the costs involved.

See the: Bay window costs price guide>>

Costs vary due to many factors including; site access, raw materials and the complexity of the work required.

Carving a bay window at London Stonemasonry's workshop

Pictured: A bay window being carved at London Stonemasonry’s workshop

A client testimonial

Sarah O’Brien, homeowner, Chiswick, London, W4:

“The new bay window [by London Stonemasonry] is a testament to the skill of these amazing stonemasons. The Bath stone they used is beautiful and adds a warmth to the house. Its carving is exquisite and matches all the details of neighbouring properties. It’s precision perfect – when my new sash windows were fitted the company commented that they had never fitted a window where no adjustments were necessary.

“The added bonus of using London Stonemasonry was that their team could handle all aspects of the renovation – from removal of the render, rebuilding and damp proofing the bay window, re-roofing the structure and making good inside my home.

“I wholeheartedly recommend their skills to anyone who is looking to do a similar project.

New bay window by London Stonemasonry

Pictured: Sarah’s new bay window by London Stonemasonry

Making an insurance claim? We can help

At London Stonemasonry, we provide thorough assessments and detailed reports for homeowners that are making insurance claims for building damage, damaged bay windows and broken stonemasonry.

When you contact us, we first evaluate the project size and scope. For minor facade damage, we can provide quotes based on site visits or photos.

For more complex problems like bay window subsidence or structural cracks we send our qualified structural engineer to conduct a detailed assessment. We then prepare a comprehensive report outlining the damage, necessary repairs, and costs. Homeowners typically forward this report to their insurer, but we can also send it directly if preferred. Find out more about our buildings insurance claims process.

A bay window we repaired, after sending a report to the insurer

Pictured: A bay window we repaired in Dulwich, after making a damage assessment and report for the homeowner’s insurer. See the case study.

Get a free estimate

Our free quotation process is straightforward:
  • Contact London Stonemasonry.
  • We arrange a viewing of your window and discuss the options with you.
  • Then we produce a costed report for your approval.

See also