St John’s Wood Basement & Extension Project Progress Update

Posted on ZXCZXC28 July 202628 July 2026 by FJDigital

Structural Milestone Reached

Our latest progress update video showcases how our ongoing St John’s Wood basement and extension project continues to move forward, with another major structural milestone now complete. Following months of carefully planned excavation, underpinning and basement construction, the project is now transitioning into the next exciting phase as the permanent structure begins to take shape.

Working alongside an experienced team of consultants and specialists, we’re continuing to deliver this complex residential project with precision, careful planning and close attention to detail.

Moving Beyond the Basement Structure

When we last shared an update, the team had successfully completed the extensive underpinning works and excavation required to create the new basement structure.

Since then, significant progress has been made across the site. One of the most important stages has been the installation of the permanent structural elements that will ultimately support the existing property as construction continues.

Throughout these works, the original house has remained safely supported by an engineered temporary structure. This carefully designed solution has allowed construction to continue while protecting the integrity of the existing building during one of the most technically demanding stages of the project.

Collaborative Structural Engineering

Projects of this complexity rely on close collaboration between multiple specialists. The temporary support system and permanent structural solution have been developed in partnership with Malci, Richard Tant Associates, and Architecture for London, ensuring every stage of construction is carefully engineered before work begins on site.

With the permanent structure now installed, the next step will see the construction of the new concrete deck, allowing the team to begin opening up the internal spaces and preparing the property for the next phase of the build.

Elsewhere on the project, screw piles have now been installed to support a new external deck structure.

Once the project is complete, this area will become home to a bespoke sauna, adding another premium feature to this extensive residential renovation. During construction, however, the deck will provide a practical temporary solution by relocating the site’s welfare facilities outside of the house.

Moving the welfare accommodation away from the existing building will allow our team to fully focus on the internal construction works as the project progresses into its next stage.

Building Out the Extension

With the major structural works nearing completion, attention will now turn towards continuing the masonry works, constructing the new extension and gradually transforming the structure into a finished home.

As the external envelope develops, internal fit-out works will begin to gather pace, marking a significant shift from heavy structural engineering towards the craftsmanship and finishing stages of the project.

This transition represents another key milestone in what has been a highly technical build requiring careful sequencing, specialist engineering and close collaboration between the wider project team.

Follow the Project as it Progresses

We’ll continue to share updates as work progresses on this exciting St John’s Wood project, showcasing each stage of the build from complex structural engineering through to the final high-end interior fit-out.

Be sure to check back for future progress updates as the project continues to evolve or check our news page to see what else we’ve been up to!

Ealing Project Update: Basement Structure and Extension Progress Taking Shape

Posted on ZXCZXC12 June 202612 June 2026 by FJDigital

We are pleased to share the latest progress from our substantial refurbishment and extension project in Ealing, where work continues on the transformation of a large Victorian property into a highly efficient, low-carbon family home. Designed by Beasley Dickson Architects with structural engineering by Foster Structures, this project combines extensive structural alterations with a high-end contemporary finish.

Project Overview

This ambitious scheme includes:

Complete strip out of the existing property
New roof structure and roof coverings
Large rear extension
Extensive alterations to the existing structure
New basement beneath the existing house
Ground source heat pump installation
Low-carbon, high-efficiency building upgrades
Complete luxury interior fit out

The project has been carefully designed to modernise the property whilst retaining the character of the original Victorian home.

Significant Structural Progress on Site

Recent weeks have seen major progress across several key areas of the build.

The new rear extension is now clearly visible, with the walls, structural steelwork and floor structures all coming together. The large open-plan rear elevation has been formed using substantial steel beams, creating the expansive internal living spaces that will define the completed home.

One of the most striking elements at this stage is the scale of the structural works. The combination of steel framing, load-bearing masonry and carefully coordinated temporary works has allowed us to create large openings whilst maintaining the integrity of both the existing building and the new extension.

The photographs also show the impressive brickwork detailing that will help seamlessly connect the new structure with the character of the original property.

Basement Construction Continues

Alongside the extension works, progress continues on the new basement construction beneath the existing house.

Creating a basement below an existing structure requires meticulous planning and engineering. The excavation and retaining works have now allowed the basement spaces to take shape, with structural walls, waterproofing systems and access points becoming increasingly visible.

The basement will provide valuable additional accommodation whilst maximising the available footprint of the property without impacting the surrounding site.

As the project progresses, further structural elements will be completed before attention turns towards internal layouts, services and finishes.

Looking Ahead

With the main structural framework continuing to progress, the scale and ambition of the project are becoming increasingly apparent.

Over the coming months, works will continue on the roof structure, external envelope and internal construction as we move closer towards the next phase of this exciting transformation.

We look forward to sharing further updates as this exceptional Ealing project continues to develop.

Hosting Architecture for London at our St John’s Wood project

Posted on ZXCZXC30 March 202630 March 2026 by FJDigital

A key milestone marked with a full team site walkthrough as the structure begins to emerge

Our team was pleased to host the team from Architecture for London at our ongoing site in St John’s Wood. The team joined us for a detailed walkthrough of the project’s progress. With everyone arriving bright and early, it was a great opportunity to bring together the wider project team. Together, we were able to share a closer look at the work completed to date.

The visit came at a significant stage in the build, with the basement now fully excavated following several months of complex groundworks. Delivered in collaboration with Malci and Quorum Consulting Engineers, this phase has been a major part of the programme, and seeing the scale of the excavation in person really emphasised the level of coordination and precision involved.

With the structural design by Richard Tant Associates now beginning to take shape on site, the early form of the new home is becoming visible. Walking the team through this stage alongside our clients created a real sense of momentum, marking a turning point in the project as it transitions from groundworks into the build phase. It felt like a milestone moment, similar to a topping out, just experienced in reverse.

Architecture For London On Site:

Moments like this highlight the importance of collaboration across the full project team. Bringing architects, engineers, contractors and clients together on site not only reinforces the shared vision for the project, but also provides a valuable opportunity to reflect on progress and align on the next stages.

With the sun out and strong progress being made, it was a great reminder of why the work behind the scenes matters. We look forward to continuing to share updates as this exciting project develops further.

To see more of our work, visit our projects page and stay tuned for further updates as this build continues to progress.

Major Progress on Our Ealing Refurbishment Project

Posted on ZXCZXC10 March 202610 March 2026 by FJDigital

Impressive structural alterations, a new basement and a complete rebuild of the roof are transforming this Ealing property.

Our team has been making strong progress on an extensive Ealing refurbishment project. This project has involved stripping the existing property back to its core before transforming it into a contemporary, luxury home.

Working alongside architects Beasley Dickson and structural engineers Foster Structures, the scheme combines structural alterations, a new basement and a full interior fit out to high-end specifications.

The result will be a stunning home designed for modern living.

A Full Structural Transformation

This project began with a full strip-out of the existing house. The team removed internal finishes and structural elements to prepare the property for significant alterations.

The scheme includes:

A new roof structure and slate coverings
A rear extension to increase internal space
Structural alterations throughout the existing building
A new basement beneath the property
A premium interior fit out

Together, this will transform the property both structurally and aesthetically.

Roofing and External Works Taking Shape

Recent progress on the roof has been particularly impressive. The new roof structure is now in place and the slate coverings are being installed.

The slate roof retains traditional character while providing long-lasting performance and durability. New dormer details and carefully finished rooflines are helping to add overall definition to the home.

As these external works continue, the architectural elements of the property will come together beautifully.

Basement Construction and First Fix

Beneath the existing structure, a new basement is being created to add valuable living space.

The first fix stage in the basement is now complete. This includes plumbing and electrical infrastructure that will support the future function of the space.

Once finished, the basement will integrate seamlessly with the rest of the house and provide additional living areas.

Designed for Efficiency and Low Carbon Living

This project is not just about creating space, but performance and sustainability.

The home will incorporate a ground source heat pump, helping to reduce operational energy use and carbon emissions. Combining modern insulation with high-efficiency systems, the property will deliver strong environmental performance.

These measures support the growing demand for low-carbon residential properties.

Looking Ahead

With the structural work well underway, the project is progressing toward the next phases of construction.

Over the coming months, the team will continue working on completing the extension, external envelope and internal build stages before moving onto the internal finishes.

We look forward to sharing further updates as this impressive Ealing refurbishment continues.

To view more of our recent projects please click here.

Ealing Residential Redevelopment – Project Progress Update

Posted on ZXCZXC22 January 202623 January 2026 by FJDigital

Basement and Roof Milestones Mark Major Progress on this Complex Ealing Redevelopment

Works are continuing at pace on our major residential redevelopment project in Ealing, with significant milestones now reached both above and below ground.

This carefully planned scheme involves the full strip-out of the existing house and the construction of a new basement beneath the original footprint. Additionally, we will complete a rear extension, extensive structural alterations and a complete high-end internal fit out. Alongside the architectural transformation, the project has been designed with a strong focus on low-carbon performance and long-term energy efficiency.

Basement Structure Nearing Completion

One of the most complex phases of the build is now approaching completion, with the new basement structure largely formed beneath the existing property. We have carried out extensive structural works to safely create the additional level, providing valuable new living space while maintaining the integrity of the original house above.

A standout feature at this stage is the bespoke staircase which now links the basement seamlessly to the rest of the home. Designed as both a functional and architectural element, the staircase integrates seamlessly into the structure and plays a key role in how the new spaces connect and flow once the project is complete.

New Roof Structure In Place

Above ground, the project has reached another major milestone with the new roof structure now installed. The framing is complete and clearly defines the updated form of the house, marking a visible step forward in the transformation of the property.

With the roof structure in place, the building is beginning to take its final shape, allowing the project to move confidently into the next stages of construction and internal works.

With the roof structure now established, the building envelope is beginning to close in, providing a clear platform for the next phases of the programme. This stage allows greater coordination of follow-on trades and supports the smooth transition into weatherproofing, services installation and internal fit out as the project continues to progress.

Sustainable Systems and High-End Finish

Sustainability is a core part of this redevelopment. The house will benefit from a ground source heat pump and a low-carbon, high-efficiency design approach throughout. This will support long-term energy performance without compromising on comfort or quality.

As the structural phases conclude, focus will continue to shift towards the high-end fit out, where detailing, materials and craftsmanship will define the finished home.

Collaborative Delivery

This project is being delivered in collaboration with Beasley Dickson Architects, whose considered design has guided the transformation of the property. Additionally, Foster Structures have supported the complex structural requirements of both the basement and superstructure works.

To see more of our recently completed projects with a similar scope, please click here.

Building Below Ground: The Complexity of Basement Construction

Posted on ZXCZXC5 January 20265 January 2026 by FJDigital

Why Basement Construction Requires Specialist Experience

Basement construction has become an increasingly popular way to create additional space within high-value residential properties, particularly across London and the surrounding areas. Whether forming part of a new build or a complex conversion beneath an existing home, basements offer valuable accommodation without compromising the external footprint of a property.

However, basement construction is one of the most technically demanding aspects of residential building. It requires specialist knowledge, careful planning and an experienced contractor capable of managing risk at every stage.

Basement Construction is not Standard Groundworks

Unlike typical groundworks, basement excavation involves working at significant depth, often within restricted urban sites and in close proximity to neighbouring properties. Ground conditions can vary considerably and the risks associated with excavation increase rapidly the deeper a project goes.

Managing ground stability, sequencing works correctly and implementing appropriate temporary support systems are all critical. Any error at this stage can have serious implications for surrounding structures, which is why basement construction demands a contractor with proven experience in deep excavations and complex below-ground works.

Structural Complexity Below Ground

Basements frequently involve major structural interventions. These can include underpinning existing foundations, installing extensive steelwork and carefully transferring loads to allow the structure above to remain stable throughout construction.

In refurbishment and conversion projects, this work is often carried out beneath occupied homes or alongside neighbouring properties. This requires meticulous coordination with structural engineers and a detailed understanding of how existing buildings behave when altered. Precision and experience are essential to ensure safety, compliance and long-term structural integrity.

Waterproofing and Long-term Performance

One of the most critical elements of basement construction is waterproofing. A basement is only as successful as its ability to remain dry and perform well over time.

Effective waterproofing systems must be correctly designed, installed and integrated with the overall structure. This often involves multiple layers of protection and close coordination between designers, engineers and specialist contractors. Poor decisions or shortcuts at this stage may not become apparent for years, by which time rectifying issues can be highly disruptive and costly.

A specialist contractor understands the importance of getting waterproofing right first time and takes a long-term view of performance rather than focusing solely on short-term build considerations.

Logistics and Site Management Challenges

Basement construction brings unique logistical challenges, particularly in urban locations. Restricted access, limited working space and the need to remove large volumes of excavated material all require careful planning.

Noise, vibration and safety considerations must be managed sensitively, especially when working close to neighbouring properties or within conservation areas. A well-managed site, clear communication and experienced supervision play a key role in minimising disruption and maintaining good relationships with surrounding stakeholders.

Coordination with the Wider Project

Basements rarely exist in isolation. They are typically integrated into wider new build or refurbishment schemes, requiring seamless coordination with the rest of the construction programme.

Services, drainage, plant rooms and structural elements all need to align with the above-ground design. Early contractor involvement and close collaboration with architects and engineers helps to ensure that basement spaces function effectively and complement the overall scheme rather than creating constraints later in the build.

Why Experience Makes the Difference

Basement construction carries a higher level of risk than most residential building work. It demands technical expertise, disciplined site management and the ability to anticipate and mitigate challenges before they arise.

An experienced contractor brings not only practical knowledge but also the confidence to manage complex conditions, make informed decisions and deliver a basement that integrates seamlessly into the finished property. This experience is particularly valuable on high-end residential projects where quality, longevity and performance are paramount.

At Harris Calnan, basement construction forms a core part of our work. Our experience across complex new builds and conversions allows us to deliver technically demanding basement projects with care, precision and confidence, ensuring robust, high-quality results that stand the test of time.

Project Walkthrough: St John’s Wood, Low Carbon Renovation

Posted on ZXCZXC3 October 20253 October 2025 by FJDigital

We are pleased to share a video walkthrough of the early stages of our latest St John’s Wood renovation, delivered in collaboration with Architecture for London. Click on the video to learn more about this fantastic project.

The walkthrough shows the substantial temporary works now in place. We’ve installed steels and supports to extend the ground floor and secure the structure. This careful preparation allows excavation of the new basement to begin safely and efficiently.

This renovation will transform the existing house with a full strip out, a lowered and extended basement, and a high end fit out. Every stage of the build is guided by a low carbon, high efficiency approach, ensuring the finished home will be both elegant and sustainable.

Although the project is still at an early stage, the walkthrough highlights the scale of the work involved and the precision required. It offers an inside look at how complex residential projects are carefully managed from the very start.

We will continue to share updates as the project develops, giving further insight into each stage of this St John’s Wood renovation.

To see some of our finished finished projects, click here.

foundation works for substantial basement structure

New Build with Expansive Basement in St Albans

Posted on ZXCZXC24 September 202524 September 2025 by FJDigital

Harris Calnan recently delivered a striking new build residence in St Albans, following the full demolition of the existing property. The scheme involved the construction of a contemporary home complete with a large basement. This basement quickly became the defining feature of the project.

We usually focus on substantial developments across North London so the scale of the basement excavation made this project a perfect match for our expertise. Over the years, Harris Calnan has developed a strong record in complex basement works. Our experience covers deep excavations, specialist waterproofing and the careful coordination of services within tight structural constraints.

These skills allowed us to manage every stage with confidence and ensure the basement integrated seamlessly into the overall design of the home.

From groundworks through to completion, our team oversaw each element with care and precision. The result is a modern residence built to the highest standard, combining contemporary architecture with robust construction that will stand the test of time.

We worked alongside Neil Choudhury Architects on this project and collaborated with a skilled group of contractors and suppliers who contributed their craftsmanship and expertise.

If you would like to discuss an upcoming project with us, please get in touch.

Contact us
📞 020 8968 8877
📧 [email protected]

To see more of our projects please click here.

Luxury Residential Transformation, Ealing

Posted on ZXCZXC28 August 202528 August 2025 by FJDigital

At Harris Calnan, we are currently delivering a full residential transformation of a private property on Carlton Road, Ealing, working closely with Beasley Dickson Architects and Foster Structures. This ambitious scheme brings together our expertise in complex construction with a strong design vision, creating a contemporary home finished to the highest specification.

The works include a complete strip-out of the existing house, the formation of a new basement beneath the original footprint, a rear extension, and a new roof structure with coverings. We will complete the property with high-end finished throughout, all designed with an emphasis on low-carbon, high-efficiency performance supported by a ground source heat pump.

On site, we are pleased to be collaborating with Malci Construction who are progressing the basement works, AGA Scaffolding who have delivered the elaborate temporary works, and Maralb Construction who have completed the roof strip ready for inspection. Recent site meetings with the wider project team have allowed us to review progress in detail and carefully coordinate the next stages of the build.

From light-filled new spaces to a bespoke basement designed for modern family life, the property will not only reflect architectural excellence but also provide a comfortable, sustainable and future-ready home for years to come.

This project is a prime example of how we bring together skilled craftsmanship, collaborative working, and sustainable design solutions. Once complete, this residential transformation will combine architectural elegance with modern energy-efficient performance, reflecting both the ambition of the client and the expertise of the team.

See the gallery below to see some of the work in progress and if you’d like to see more of our recently completed projects, click here.

Progress Update: High End Renovation, Islington

Posted on ZXCZXC8 August 20258 August 2025 by FJDigital

Work continues to move forward at pace on our high-end renovation and basement extension project in Islington, where we’re delivering a complete transformation at 6 Highbury Hill.

Designed in collaboration with Cousins & Cousins Architects, this project includes a full strip-out of the existing property, a lowered and extended basement, and a high-end fit-out throughout. With Stuart Eley as Quantity Surveyor and Constructure as structural engineers, the team is pushing ahead with both care and precision.

WhatsApp Image 2025 07 04 at 14.43.48 ca8f7504

Following recent progress on the basement shell, our in-house team has worked closely with Newton Waterproofing to ensure a robust waterproofing system is in place, ready for the installation of a polished concrete floor by Lazenby.

Externally, we’re restoring the original façade using a careful blend of new and traditional techniques, while above, the new roof is progressing well under full temporary cover.

A recent walk-around with the client and our site manager Brian provided a chance to review the ongoing work across every level of the home. With refurbished internals taking shape and the project moving into the next phase, this one is shaping up to be a standout example of collaboration and craftsmanship.

Most recently, we’ve also had the pleasure of working alongside Capital Rewire and Ember Lighting, who are supporting the next stage of internal works. This follows a visit from Estimus London, who installed the new slimline double glazed timber sash windows, now in place across the rear elevation.

Check out some of fantastic work in progress shots below to see the size of the incredible new basement space. We look forward to sharing more as the project develops.

To see more of our most recent work, please see our news page, and for completed projects and other high end renovations, check them out here.