Our Expertise Complex Retrofit
Residential Listed Building Works
Commercial Listed Building Works
Whole Life Sustainability - Retrofit
Whole Life Sustainability - New Building Life Cycles
Reclaim + Re-use
Detail + Character
As a practice we have been working with existing building fabric for several decades - from Grade 1 Listed architecture to Conservation Areas to more modest buildings that at first glance might not look especially promising.
In the current context, it makes sense to continue with a policy of 'Retrofit First'making use of not just the heritage and character of existing buildings, but also re-using their resources and associated embodied carbon whilst significantly improving their operational energy performance.
In certain circumstances a new build can be more appropriate, and in these situations we are conscious that we are creating a new 'building life cycle'. Where possible we use these situations to contribute to an emerging language of regenerative, low carbon architecture, often using renewable plantbased materials.
In this context we focus our efforts on three key areas of architectural practice:
▪ Retrofit at Work
▪ Retrofit at Home
▪ New Building Life Cycles
In all types of project, CSK Reclaim offers an additional service of sourcing and re-using vintage and secondhand products to create bespoke interiors.
For commercial projects, retrofit is most often viable for buildings with a robust structure, generous floor-to-ceiling heights and large floor plates for flexibilty. Our approach to these projects is to retain and restore any quality fabric, extend where necessary, add additional linings and finishes only where essential, and incorporate services so that they can be easily adapted and replaced.
We are very experienced at complex retrofit, involving several interlinked buildings, mixed uses, phased construction etc.
Our residential projects range from light-touch interiors to 'deep retrofit' and large extensions, using forms and materials that are sympathetic to the historic fabric. We are also very used to working within the constraints posed by Listed buildings, and in Conservation Areas, flood zones, SSSI and Green Belt.
Where new build is necessary, we aim to work with materials and processes that acknowledge the interconnected relationship between the building life cycle and the foundational earth systems that underpin everything we do.
We continue to aspire to a whole life approach to environmental sustainability, considering both embodied carbon and operational energy, as well as addressing material systems, and the complex processes of assembly in relation to the potential for disassembly and reuse.
CSK are experienced in the often complex process of getting the most out of projects and sites with the following characteristics:
▪ A range of different programmes
▪ Several interlinked constrained plots
▪ Buildings of different periods and types of construction requiring significant upgrading in terms of performance
▪ Different levels in section
▪ Conservation Area
▪ Economic driver to maximise NIA
▪ Mixture of demolition, retention and renovation and new build extensions
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CSK have developed expertise in the retrofitting of historic fabric, in particular:
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• Restoration of historic fabric using traditional craft techniques
CSK have developed expertise in the retrofitting of historic fabric, in particular:
▪ Working with Georgian, Victorian, Edwardian and Queen Anne Houses
▪ Facade retention
▪ Grade l, Grade ll* and Grade ll listed buildings
▪ Gaining consent for contemporary additions to historic fabric
▪ Restoration of historic fabric using traditional craft techniques
Architecture is about more than just goodlooking buildings - the built environment is also a series of time-based processes with environmental impacts at every stage.
We have developed the diagram above as a tool for thinking about architecture as a 'life cycle' - in which the building is a temporary condition at the apex of the flow of materials and energy over time.
In order to engage architects, clients and society at large with issues of environmental 'sustainability' in construction, we believe it is important that this whole life approach is expressed in the buildings we make - so that Form Follows Life Cycle.'
In the life cycle diagram the building sits at the top of the value chain in terms of materials and energy - therefore it is important to maintain the life of the 'architectural artefact' for as long as possible.
However it is also the case that the built environment has to respond to constantly improving performance standards and changing requirements in general.
In this context the retrofit or adaptive reuse of existing structures are very often the most logical and sustainable strategies.
Retrofit is often undertaken in order to upgrade the building fabric and systems to minimise operational energy use. The re-use of as much existing structure as possible also minimises embodied carbon - and can add architectural character.
The 'retrofit first' assumption should be tested against outcomes e.g. quality of fabric, accessibility, economic and social sustainability etc.
Arup's Frank Duffy first coined the concept of 'shearing layers', stating that:
"Our basic argument is that there isn't any such thing as a building. A building properly conceived is several layers of longevity.'
In the context of retrofit, this means adding new layers of construction to the existing structure in such a way that they can be easily removed and replaced without causing significant or irreparable damage to adjacent layers.
Externally this approach relates to elements that address moisture, thermal performance and weathering.
SHEARING LAYERS - INTERNAL
Internally this approach relates to the installation of contemporary serviceselectrics, data, water, heating, cooling and MVHR (energy-efficient air-handling) - as well as interior linings, decorative finishes and furniture.
It is often a good strategy to minimise the number of layers required - does the building really need ceilings or plasters or paints?
Services are an increasingly significant part of architecture, so it often makes sense to leave these exposed so they can be easily maintained - and indeed replaced, which can be required as frequently as every 15 years.
For projects were a new building is necessary, every stage of the architecture life cycle has to be considered:
A building is an ongoing process that consumes both energy and materials.
Earth systems are interconnected material processes that are the foundations of everything we make, ranging in timescale from the geological to the biological.
In between these are Human systems through which the built environment is madeextraction, fabrication, construction - and then unmade - disassembly, reuse, recycling and return to the Earth systems.
Using materials from regenerative Earth systems - like timber and cork from the biosphere and earth from the pedosphere - places the emphasis on preserving their integrity throughout the building life cycle, so that they can be returned to Earth systems at the end-of-building-life. It is also crucial to manage our relationship with these systems in a way that does not adversely affect their health and regenerative capacity.
Using materials from systems that are effecitvely non-regenerative - like stone from the lithosphere - places the emphasis on maintaining circularity through re-use and re-fabrication.
We strive to create an 'Economy of Means', using strategies that:
Use relatively unprocessed materials that require low energy during manufacture and fabrication.
Minimise the total number of processes required to create a building envelope to meet current performance standards.
Avoid the creation of 'hybrid' materials, components or assemblies that cannot either be easily separated, recycled or returned directly to Earth systems.
Construction can tend to be the stage at which materials become irretrievably muddled up and stuck together. Techniques that maintain 'reversibility' include:
Dry-jointed methods that enable 'Design for Disassembly' e.g. mechanical fixings that are visible and easily accessible.
Minimal use of hybrid construction such as reinforced concrete.
Minimal use of wet trades and finishes.
Longevity of the building structure is also a critical factor, and this can be encouraged through the design of 'loose-fit' structures.
Most building components (and often buildings) reach an end-of-life scenario at some point.
Reuse: This is the most efficient method of retaining the material and energy embedded in a building component.
Recycle: Less desirable than reuse, but can reduce embodied carbon in the next life cycle e.g. recycled steel.
Return: Material that can't be reused or recycled can either be used to generate energy (W2E), returned to a regenerative earth system, or returned to non-regenerative systems as spoil.
Most of us spend the majority of our days inside buildings either at work or at home, so we believe that buildings should provide rich sensory experiences that combine visual grain, tactile texture, colour, warmth and history.
AERIAL VIEW TO INDICATE SCOPE OF REDEVELOPMENT AND EXTENT OF SITE
110 Marylebone High Street is a rich architectural composition that is the result of weaving together a complex range of ingredients:
▪ Four different programs on several levels with access from three separate streets
▪ Selective demolition, restoration and retrofit of historic fabric
▪ A series of new extensions on a constrained site in a Conservation Area in Central London
▪ Resolution of different floor levels between building plots
LAYER: FACADE
The project included a section of new build on Vincent Street in order to tie the separate existing buildings together. In Planning terms it was important for this new façade to relate to the solid impervious nature of the adjoining brick façades, whilst also being designed to allow lots of natural daylight deep into the building on this very narrow street.
This inherent contradiction led to the rich detailing required for the fenestration design, including the use of translucent marble panels.
Many clients and tenants who live in the vicinity of the building have commented on the positive enhancement to St Vincent Street.
The unique history of this site is echoed in the variety of uses, the rich palette of old and new materials, and an honest expression of construction. Design decisions are aimed at both environmental sustainability benefits and the creation of architectural character - for example the omission of finishes reduces resource use and also celebrates the imperfect nature of exposed structure, both existing and new.
Repairs to the historic fabric were restricted to structural repairs only and new finishes used sparingly, minimising material waste and maximising adaptability – always considering the life cycle of the building. The outcome is a rich patchwork of exposed masonry scars interspersed with moments of contemporary detail.
Another example of the link between environmental concerns and architectural character would be the exposed steel access floors which run throughout the offices. We had noted how often tenants moved into a finished space which had been carpeted and these carpets were immediately stripped out to allow the new owner to make their mark. We carefully designed these floors around columns etc to allow them to be left as a final finish should the tenant wish.
Although we have no data on the embodied carbon, it is estimated that more than 60% of the existing structure was retained.
Embodied carbon going forwards should also be minimised over the building life cycle as new connections and installations were designed for disassembly where possible.
Services were also carefully coordinated and exposed, allowing them to be easily adjusted to suit various occupiers whilst being part of the overall aesthetic.
LAYER:
Economy of means: whether working with existing fabric or introducing new elements of construction, the aim is to generate as much architectural character from using as little as possible – from newly exposed clinker ceilings to bare raised floor tiles and exposed services.
CASE STUDY 02
COUNTRY HOUSE
WARGRAVE, BERKSHIRE
The refurbishment includes a large contemporary rear extension housing a new kitchen and master bedroom suite at first floor. The siting of the extension was chosen to avoid detrimental impact to the significant, historic fabric.
The overall form of the rear extension is intended to continue the gable-shaped dialogue of the house. It offers a clearly contemporary addition that is respectful to the host structure and responsive to the surrounding context. This is achieved by ensuring that the scale of the addition is set back from and below the existing gable as a subservient addition. This also ensures that the extension does not interfere with the architectural feature of the tile creaser details at the eaves and ridge.
The extension uses the existing palette of materials to make real connections with the main house, painted brickwork and terracotta tiles, but the way these materials are detailed is explicitly contemporary so that this reads as a new addition. The glazed link provides a clear demarcation and successful juxtaposition between old and new.
An example of this detailing is the way the roof tile folds down to become tiled wall hanging with a concealed gutter. Contemporary slot windows also fold down from the roof to the wall.
The existing roof covering was found to be in a very poor state with an un-insulated structure leading to a degradation of the building fabric as a whole. Listed building consent was obtained to fully re-tile the roof and allowed for the opportunity to upgrade and insulate.
The use of natural plant-based materials such as wood fibre insulation and the traditional technique of chestnut lathes with a lime plaster finish, allows the building to breathe and move, ensuring its longevity.
Aside from the practical advantages of this approach, the quality of the space and experience of the occupant is also enhanced, providing a softer acoustic and aesthetic atmosphere.
This country house has a main entrance hall at the heart of the plan, this dates from the early 16th century.
In the reconfigured house plan, this hall is the first room guests enter, and it is from here that they access the main living accommodation and kitchen.
This is clearly a space that requires impact, the tapestries were restored, the timber rafters sanded back and the original flooring which was beyond repair was replaced with a new contemporary oak parquet.
A large stone fireplace and hearth in keeping with the period of the house was sourced from a reclamation yard.
All services were replaced including new LED lighting throughout.
Both the main staircase and secondary staircase were re-designed. Simple, contemporary timber detailing was applied to the design of both staircases to compliment the aged timber frame on show in the walls and ceilings.
The same species of oak timber was specified to make the material connection with existing. The existing oak beams which had been treated with an unattractive dark stain were sanded back to reveal the beauty of the natural wood.
The kitchen is located in the early twentieth century addition to the house and links the old house into the new extension. This provides an open plan kitchen, dining and living space. The configuration of the existing layout was such that there was no direct view of the river from the main reception rooms. The new extension was designed specifically to address this and provides a new family room, which has been elevated to maximise the vista.
The brief from the client was for a wholesale refurbishment and extension to prolong the life of the house and make it a sustainable place to live in terms of ongoing operational energy costs.
The challenge was how to retrofit the historic fabric to meet contemporary requirements for well insulated, air tight buildings and there was also a desire to forge a greater visual connection to the river and grounds from the accommodation in the new wing.
New contemporary oak joinery complements existing oak beams in the new boot room. Finishes are simple and robust.
CSK ARCHITECTS
Developed for a biodynamic organic farm in Berkshire, this innovative typology combines farmworkers cottages + field kitchens + farm shop + conference room + Greenhouse.
The project targets low embodied carbon through the specification of plant based materials - timber & hempcrete, lime render, clay plaster, limecrete ground floor slab, bespoke timber doors and windows.
This palette of natural and vapour-permeable materials is also aimed at excellent indoor air quality.
The central Greenhouse is a flexible and passive solar space that can be used for educational purposes, growing food, residents' dining, farm events and generally socialising throughout the year.
The central Greenhouse is a flexible and passive solar space that can be used for educational purposes, growing food, residents' dining, farm events and generally socialising throughout the year.
The project is net zero operational carbon and includes the use of on-site resources - solar energy captured via the Greenhouse glazing and a large PV array on the roof; a ground source array with heat pumps; and natural cross ventilation (inc. solar shading strategy).
The site also includes a drainage field for on-site processing of foul drainage, and a landscaped infiltration pond fed by rainwater run-off.
In support of the main project, the farm and CSK collaborated on a prototype building - the farm experimented with growing and harvesting hemp; CSK tested innovative casting techniques and undertook some performance-related R&D with UCL and Max Fordham; and together with interested locals, school children and university students, we all took the opportunity to try our hand at 'hempcreting'.
CSK ARCHITECTS
WINDSOR, BERKSHIRE
The project is a contemporary revival of St. Leonard's Hill that will be a circular economy exemplar and a LETI pioneer project.
CSK Architects have been granted planning permission for an innovative net zero carbon dwelling that the regional Design Review Panel have judged to be of exceptional design quality. ‘Very special circumstances in the Green Belt' was approved with unanimous support from The Royal Borough of Windsor & Maidenhead.
Located on the historic site of an C18th mansion that was home to two former British prime ministers, the proposal has also been commended for its approach to both sustainability and heritage. The project will exploit the unusual historical circumstances of the site to become a circular economy re-use exemplar, aiming to build the loadbearing masonry structure using only stone and brick salvaged from the rubble of the original house that is now strewn around the gardens. The typology of the courtyard house has been used to incorporate a historic stone colonnade, the only part of the original mansion still intact.
The proposal represents the latest stage in the historical life cycle of the property, re-inhabiting the site for at least several generations to come, and of course it is hoped that the design quality of the house will result in its continued use over hundreds of years. If or when for any reason the building reaches the end of its life, it has been designed in such a way that the stone and timber structure will be able to contribute to another iteration of the English country house - or indeed any other type of building that might be required in this location in the future.
We made maximum use of the foundations and the existing ruin was incorporated into the design of the courtyard house, becoming the fourth wing of the courtyard.
A rigorous and thoughtful design process has enabled the sympathetic utilisation of the existing ruins in the new scheme. Initially a full three dimensional mapping of the ruins was carried out. The information from this informed a spatial strategy for the new house plan, with the colonnade and vaults themselves becoming the fourth wing of the proposed courtyard house.
Great are the ideas that ruins awaken in me. Everything is annihilated, everything perishes, and everything passes away. There is only the world that remains. There is only time that endures. How old this world is! I walk between two eternities.
This project focuses on the re-use of on-site resources to create architectural character and minimise embodied carbon. It is a circular economy exemplar benchmarking new standards for the Royal Borough of Windsor & Maidenhead.
Existing brick and stone, which is scattered throughout the site, is being salvaged for re-use. The design of the new house has evolved from this reclaimed material with a language of brick arches at lower ground level and a trabeated stone frame at upper ground level.
The brickwork will use lime mortar and the stone will be retained in larger pieces where possible to allow for future re-use, allowing circular construction into the future. All of the stone from the site was gathered, numbered and scanned to create a digital quarry.
Stone re-use project: both for structure and cladding. We assembled a test portal with the help of expert stone masons. The goal was to express re-use through minimal machining. In this way the elevations developed a unique architectural character.
As part of the feasibility study of re-using stone on the site for the structural portal we did a full size test mock-up. This exercise was carried out in collaboration with UCL.
We were keen to find architectural character through re-use. Where possible the stone is left un-cut as a memory to the former building. Digital scanning technology was employed for maximum stone use.
Alongside the stone re-use, all the bricks were collected and sorted and stacked on pallets. Tests were undertaken as to the brick strength. Sample panels were prepared with lime mortar exploring a variety of brick bonds. In some of the sample panels we used the broken bricks to both minimise waste and create architectural character. This creates rustic coursing towards the base of the building.
Phase 1 - aerial view showing foundation pattern of original house. Existing footings reused where possible - design of house aligned to maximise re-use. New foundations stitched in where needed.
