Conservation Insights
A series exploring the history, significance, and technical care of historic buildings, sharing the challenges and solutions that preserve architectural heritage for the future.

02. Laurie Groves Baths: Looking After the Roof That Protects a Century of Social History

For generations of south Londoners, Laurie Grove Baths was far more than a municipal swimming pool. Opened in 1898 under the Public Baths and Wash-houses Act of 1846, the Grade II listed building was conceived as an investment in public health, providing swimming pools, slipper baths and laundries for a rapidly expanding industrial community. At a time when many households lacked bathrooms of their own, it offered something we now take for granted: the opportunity to wash, swim and maintain personal dignity.

Designed by local architect Thomas Dinwiddy in a confident Jacobean style, the building has continually adapted to changing needs. Its pools have hosted dances and concerts, welcomed the Anglo-Caribbean Association during a period when many venues excluded Black Londoners, and today provide studio space for students at Goldsmiths, University of London. Few civic buildings encapsulate so much of London’s social history within a single structure.

Yet, while the richly detailed façades attract attention, it was the roof that presented the greatest conservation challenge.

The Conservation Challenge

Historic roofs rarely fail because of one dramatic event. More often, deterioration begins gradually through blocked gutters, slipped slates, failed flashings and areas that are simply too difficult to inspect safely.

Laurie Grove Baths is no exception. Behind the prominent street elevations lies an intricate roofscape of pitched slate roofs, glazed lanterns, patent glazing, lead valleys, parapet gutters and concealed drainage channels. Over more than a century, routine maintenance had become increasingly difficult, leaving vulnerable areas inaccessible and allowing small defects to develop into larger maintenance issues.

Rather than focusing solely on repairing individual defects, our approach considered how the building could be better cared for over the decades to come.

Our Approach

The project combined urgent fabric repairs with carefully considered improvements that would support the building’s long-term maintenance while respecting its listed status.

Works included repairs to slate roofs, leadwork, asphalt coverings, roof lanterns, patent glazing and rainwater drainage systems, alongside the repair of defective flashings, blocked outlets and weathered detailing. Existing dormers were re-clad using traditional lead detailing more appropriate to the character of the building, while improving thermal performance.

Perhaps less obvious, but equally important, was the introduction of permanent maintenance infrastructure. New access ladders, roof walkways and discreet fall protection systems were designed to allow future inspection and cleaning of gutters, valleys and rooflights without risking damage to fragile historic fabric or compromising the building’s appearance. Located away from public views and finished in dark colours to minimise their visual impact, these interventions demonstrate how contemporary requirements can be integrated sensitively into historic buildings.

Like many successful conservation projects, much of the work is almost invisible to visitors. That is often the measure of success: preserving historic character while quietly improving performance, safety and longevity.

Lessons from the Project

One of the enduring challenges of conserving historic buildings is recognising that maintenance is itself a form of conservation.

A well-designed maintenance strategy can prevent the need for far more extensive interventions in the future. By improving access, simplifying routine inspection and addressing the causes of water ingress rather than simply its symptoms, projects such as Laurie Grove Baths help ensure significant buildings remain both usable and resilient.

For us, conservation is rarely about freezing a building in time. It is about understanding how it works, respecting its significance and making thoughtful interventions that allow it to continue serving new generations. Laurie Grove Baths has already lived many lives; as a public bathhouse, community venue and university building. Sensitive conservation helps ensure it is ready for whatever its next chapter may be.

Conservation Insight

Historic buildings rarely deteriorate because of a single failure. More often, defects begin with routine maintenance issues: blocked gutters, slipped slates or failed flashings. Designing buildings so they can be safely inspected and maintained is one of the most effective forms of long-term conservation.

David Johnson recently travelled to Kotor, Montenegro, as part of his ongoing work with the Organization of World Heritage Cities (OWHC). Accompanied by OWHC Secretary General Mikhaël de Thyse and Michal Krazucki, Director of the Warsaw Heritage Protection Department, David took part in an advisory mission focused on strengthening disaster risk management for Kotor’s UNESCO World Heritage Site.

The workshops, held on 18–19 June, brought together local stakeholders to review and update the city’s risk assessment for threats including fire, earthquakes and overtourism, and to develop a practical action plan. As Consultant for the OWHC’s Assistance Program in Case of Emergencies, David contributed to discussions that will support the implementation of a pilot project to create a strategic map and emergency evacuation plan for St. Trophimus (Tryphon’s) Cathedral and the Kotor Museum; the first project of its kind within the OWHC network.

The progress of this pioneering initiative will be presented at the 18th OWHC World Congress in Marrakech later this year, helping to share best practice in protecting historic cities and their cultural heritage.

Conservation Insights
A series exploring the history, significance, and technical care of historic buildings, sharing the challenges and solutions that preserve architectural heritage for the future.

01. Tollgate House, Hampstead Heath: Preserving an 18th-Century Landmark

On the eastern edge of Hampstead Heath, opposite the iconic Spaniards Inn, stands a small square building that quietly marks a piece of London’s transport history. The Tollgate House, a late 18th-century Grade II listed building, was originally the gatehouse where travelers paid tolls to enter land owned by the Bishops of London. Its painted brick walls, brick dental course, and ceramic tile hipped roof, along with a vaulted lower ground floor, reflect its age and functional origins.

The building appears on John Rocque’s 1746 map of London alongside the Spaniards Inn, showing a dotted line across the road representing the gate that barred passage until tolls were collected. Travelers heading into the Bishops’ land (from what we now call Hampstead to Highgate) would pass through the toll and immediately find themselves on a better-maintained road. The road to the east widened shortly after the gate, a detail that survives in the road layout today.

A Narrow Road Through Time

Despite the increasing traffic over the centuries, the Tollgate House has remarkably survived. Its location at a narrow bend opposite the inn has made it the focus of multiple proposals for removal, dating back to a 1922 report in the Hampstead and St John’s Wood Advertiser. Later, in 1961, the London County Council proposed demolition to improve traffic flow, and the debate even reached the House of Lords in 1966, when Lord Colwyn questioned whether the gate should be removed to ease congestion. Ultimately, the toll gate survived, and in 1974 it was granted Grade II listing, securing its protection under the care of Camden Council. A commemorative plaque now marks its historical significance, and a black-and-white bollard installed in 2008 protects the building from passing traffic.

Our Conservation Approach

By the time we were commissioned, the Tollgate House was unoccupied, unserviced, and suffering from significant damage. The number of vehicles passing had caused deterioration to the high-level brickwork, rainwater goods, and roof, allowing water ingress and fabric decay. Our work focused on returning the building to a weather-tight, structurally consolidated state, while respecting its historic character:

External Repairs: Brickwork repairs, repointing, and decoration of all elevations and chimney.

Roof and Rainwater Management: Structural consolidation of damaged roof areas, replacement of roof tiles to match existing, and a more robust gutter and downpipe system designed to withstand potential vehicle impacts.

Internal Conservation: Repointing and crack repairs to internal brickwork, including the vaulted basement ceiling and floors, and repair of timber doors, windows, and shutters. Low-level snorkel vents improve natural ventilation to aid drying of historic fabric.

Drainage Improvements: Installation of perimeter channels to manage groundwater ingress.

The majority of the work was like-for-like repair, with sensitive upgrades to ventilation and drainage ensuring durability while preserving the building’s historic character.

Impact and Legacy

The project achieved more than structural consolidation. By returning the building to a weather-tight state and improving internal conditions, the Tollgate House was removed from the Heritage at Risk register and Camden Council was able to let the building commercially; helping to ensure its continued use and preservation.

Tollgate House reminds us that heritage conservation is not just about preserving bricks and mortar; it’s about protecting stories, patterns of daily life, and landmarks that have shaped the way Londoners move through the city for centuries.

Conservation Insight

Historic buildings often deteriorate because the original causes of damage remain unresolved. Effective conservation is not simply about repairing historic fabric, but understanding why it failed and designing discreet interventions that prevent the same problems occurring again.

David Johnson, as a part of his ongoing work with the Organization of World Heritage Cities (OWHC), recently had the opportunity to travel to George Town, Malaysia for the ‘We Are Site Managers’ conference, where he was a key note speaker for Session 13: ‘Resources for Site Managers: Disaster Risk Preparedness and Dealing With Emergencies’. He introduced attendees to the ‘Emergency Programme’ developed by OWHC which aims to assist member cities and their site managers to identify risks, explore methods on natural and man-made disaster prevention and longer term management with a view to protect heritage sites worldwide.

We recently presented our proposal for the transformation of the Nautical Museum in Castletown on the Isle of Man to the Tynwald and various stakeholder engagement days. Interviews with Project Lead, Jon Parry, together with our animated walkthrough can be found here and here

The project combines conservation and repair of the entire historic Nautical Museum site with an architecturally distinct, sustainable and sympathetic design for a new-build display boathouse for the historic ship, The Peggy. The completed project will transform access & interpretation, combining historic collections, vibrant new interactives and displays to provide a world class, all weather attraction for Castletown, offering engaging and enjoyable experiences that will embrace and inspire visitors of all ages and abilities.

The proposal combines the highest standards of conservation and adaptation of existing historic buildings together with innovative and accessible approaches to exhibition design, visitor interaction, understanding and enjoyment.

Dannatt Johnson Architects lead a design team including Steensen Varming and AECOM, with Project Management from Fraser Randall. This team delivered our recent award-winning collaboration at the Imperial War Museum Second World War and Holocaust Galleries. Exhibition Designers Real Studios have also worked along side us, following our previous work together for the National Museum of the Royal Navy.

We are proud to be working with Manx National Heritage on this prestigious and significant site, and look forward to the exciting possibilities and opportunities that this complex and transformational project will provide. The project is currently on hiatus, while funding applications and fundraising activities are undertaken. In the meantime, we are pleased to share some of our team’s concept images for the project, presented to the Tynwald and stakeholders in recent days.

We recently enjoyed a tour of The Palace of Westminster (Houses of Parliament), kindly escorted by our ex-colleague who, having worked at DJA on projects including at Chiswick House and Dover Castle, is now involved in Strategic Estates at the Palace. It was a wonderful opportunity to hear about the large projects undertaken and overseen by her team, such as the recent refurbishment of the Elizabeth Tower; and the history of the site, as well as appreciating the variety of architectural details throughout.

DJA are proud to be one of 200 businesses taking part in the Mayor of London’s Business Climate Challenge (BCC) 2023. This programme is funded by the Mayor and works with London businesses to help them prepare for the green transition and future proof their organisation, and help them become net-zero by 2030. By committing to decreasing their energy usage by at least 10 percent a year, we will receive technical support to help us operate more efficiently, reduce energy consumption, and play our part in tackling the climate emergency.

As a practice, sustainability is already at the heart of what we do - adapting existing buildings, rather than building new is one of the greatest contributions we can make within the construction industry. We also strive to reflect this within our workplace: all of our energy is from renewable sources; all staff commute via public transport, on foot or by bike; and we operate a zero-to-landfill initiative. Having access to the support and resources provided through the BCC will push us even further in our commitment to sustainability and protection of the environment.

You can see a full list of participants and learn more about the scheme here.

We are delighted to announce that our recent competitive bid to deliver the transformation of the Nautical Museum in Castletown on the Isle of Man was successful.

The project combines conservation and repair of the entire historic Nautical Museum site with an architecturally distinct, sustainable and sympathetic design for a new-build display boathouse for the historic ship, The Peggy. The completed project will transform access & interpretation, combining historic collections, vibrant new interactives and displays to provide a world class, all weather attraction for Castletown, offering engaging and enjoyable experiences that will embrace and inspire visitors of all ages and abilities.

The proposal combines the highest standards of conservation and adaptation of existing historic buildings together with innovative and accessible approaches to exhibition design, visitor interaction, understanding and enjoyment.

Dannatt Johnson Architects lead a design team including Steensen Varming and AECOM, with Project Management from Fraser Randall. This team delivered our recent award-winning collaboration at the Imperial War Museum Second World War and Holocaust Galleries. Exhibition Designers Real Studios are also joining us following our previous work together for the National Museum of the Royal Navy. We also look forward to working alongside Island based architects Horncastle:Thomas and quantity surveying practice Magee & Co.

We are proud to be working with Manx National Heritage on this prestigious and significant site, and look forward to the exciting possibilities and opportunities that this complex and transformational project will provide in developing a new all-weather heritage visitor experience for the island. In the meantime, we are pleased to share some of our team’s concept images for the project which formed part of the tender submission.

We are pleased to announce that our recent galleries project at the Imperial War Museum, London has just been awarded the Museums + Heritage Permanent Exhibition of the Year Award. We are very proud to have been involved with such an important development and to have worked closely with such a well-established and engaged design and client team.

What the judges said:

“An outstanding game-changing, global exhibition, with decolonisation at its forefront. Embracing many difficult stories, juxtaposing them and blowing apart the traditional narrative. The Second World War and the Holocaust Galleries literally and figuratively, bring global and personal stories of humanity and inhumanity, into the light.”

Ealing Allotment Partnership: Grow The Universe

After a successful collaboration last year with Ascott Allotments, winning ‘Best Community Allotment 2021’ at RHS Hampton Court, we jumped at the opportunity to get involved again this year.

The team decided to go bigger this year, by involving reps from allotments across Ealing, to share ideas and work together to produce a garden truly representative of the diversity of people and ways of growing found in this West London borough. Ealing Allotment Partnership is a community-led group, working with Ealing Council, on behalf of all allotment tenants in the borough. EAP represents 45 allotment sites and aims to develop community involvement, offer mutual support, raise funds and generally improve all sites within the borough.

The design for 2022 is entitled ‘Grow the Universe’ and incorporates elements which are important to us at this time and are symbolised by the Mandala – a geometric configuration of symbols used in various spiritual traditions as a focus for meditation, a beautiful art form and a living tradition used in everyday life and at important celebrations.

While looking out to the wider universe, the show garden is very much rooted in the allotments of Ealing with most of the plants having been grown by allotmenteers across the borough and materials borrowed and sourced locally. Upholding the values of ‘grow locally’ and ‘involve the community’, all the plants and materials will be re-used after the show in Ealing allotment sites - a truly sustainable garden.

We are very much looking forward to the finished product and wish our allotment friends good weather and good luck for the growing season.