The latest in an ongoing AJ series looking at architects who have saved buildings from the bulldozers or brought them back to life through innovative interventions
RetroFirst Logos 2019 3
With up to 40 per cent of carbon emissions coming from the construction industry, the profession needs to find ways of adapting the type of buildings it designs, and fast.
In order to tackle the climate crisis, the default – and less carbon-hungry – option for any project should be to adapt and reuse an existing building, one of the key demands of the AJ’s RetroFirst campaign.
With the spotlight on retrofit, our series seeks to celebrate the projects that save buildings from ruin or demolition and to hear from the architects that designed them.
Today we hear from Biba Dow, of Dow Jones Architects, about how they are using a timber ’play’ stair to allow an existing Grade II*-listed Bristol terrace to become part of a growing day nursery.
Tell us about the project
This project is for a garden stair designed as a play house for a day nursery at Becket Hall in central Bristol. Our site is a fragment of the medieval city, made up of a church – the Church of St Thomas the Martyr in Redcliffe – churchyard, church hall and a terrace of four merchants’ houses.
All but the hall are Grade II*-listed. The nursery is run from the hall, in the churchyard, and one of the terrace houses.
Now a neighbouring terrace is up for sale allowing the client – former senior editor of The Architectural Review and current campus division architect for the University of Bristol, Rob Gregory – to expand the nursery.
As a forest school, lots of emphasis is placed on access to the outdoors and children play all day long in the garden. This project is a timber stair connecting the merchants’ house to the churchyard. Its existing 17th-century stair is hard to use for even the nursery’s older (three to four-year-old) children and the building has no direct access to the garden.
An open timber form with vertical open-boarded cladding and timber stair linings, this circulation stair is designed as a play house, with large windows, jettied storeys and pitching gables which respond to the informal rhythm of the rear of the houses behind.
The stair inside is made of Douglas fir plywood, making a solid form behind the cloak of Douglas fir battens. The playhouse is undercut to make a play den and to let light into the window behind, and a slide from the first floor landing allows the stair to be inhabited as a play structure. The stair lining forms the balustrades at the landings, paring down the form, and windows are placed for adults and children alike.
What other schemes for the nursery have you already worked on?
The church hall, opposite, is a single storey building with an internal mezzanine, opening onto the churchyard garden. Currently a row of small outbuildings stand between the hall and the churchyard, blocking most of its windows
Dow Jones’s earlier scheme to expand the church hall [show in red] at the opposite side of the yard [merchants’ terraces shown at bottom of model]
In 2018 we obtained planning permission for a timber structure which provides covered play areas and a stair to a new structure on the flat roof of the hall.
This 452m² building is designed so that the covered play spaces at ground and first floor level could be enclosed at a later date to provide more or bigger classrooms. Like the stair [on the opposite side of the yard], this structure is designed as a structural timber building articulated with jettied storeys which borrow language of the merchants’ houses across the churchyard, and a zinc-clad building on the roof.
Was demolition ever considered on this project?
This project is not about avoiding demolition but about creative intervention to allow wider use of an existing listed building.
The four merchants’ houses are narrow buildings, with a shop at ground level and a single stair accessed from the shop floor to the three floors above. With the stair opening off the shop, narrow stairs and small upper rooms, it is hard to find appropriate uses for the upper floors; currently, they are underused and in a dilapidated state.
By connecting the building to the churchyard and creating independent access to the upper floors, wider possibilities of uses and activities are opened up, an important factor in ensuring a future for these 400-year-old buildings.
Have the planners been supportive of your plans?
There has been much scrutiny on the impact of interventions into this rare and historic open space. We have designed this structure to be fully reversible. The merchants’ houses currently have ladder fire escapes to the rear, so existing door openings are reused.
The garden stair foundations are a shallow raft above the level of undisturbed burials, and the roots of two birch trees are protected with a Stockholm soil system.
Allowing the nursery to expand into the neighbouring building also keeps the buildings grouped through use and ownership, an important strategic element of conservation of this small part of Bristol.
What have been the main issues on this project?
The biggest challenge in protected contexts such as this is making design which has a positive impact and character without being watered down by the views on ‘weight’ and ‘harm’ so often used to measure design during the consent process.
One thing I found really interesting was that in our research for the heritage statement for the site, we read the documents relating to the brief for the church hall in 1890. At that time, the site was very enclosed and the parish council concluded that the design therefore didn’t matter, as no one would see it: ’No view of the exterior can be obtained from the street. It is, therefore, designed in the plainest manner possible.’ Too often there is a sense that everything old is always better than anything new, and that everything new is a threat, which I find depressing.
On this site, it’s the merchants’ houses which I find most interesting. I really enjoy vernacular buildings where the method of construction defines the overall design.
It’s interesting to think about making them more usable while changing them as little as possible
These have brick party walls and chimneys, and timber construction infilling between, jettied on each floor. Each of the four houses is slightly different but they form a coherent group. It’s interesting to think about how to make them more usable and practical while changing them as little as possible.
What we also enjoyed was finding references to the fact that some of the houses had historically been joined and then re-separated, evidence of the fact that buildings get adapted over their life span and now is just one moment in that ongoing process.
Dow jones section
Other than retaining the original fabric of the terrace house, explain the other sustainable elements of the scheme
The carbon benefit of the project is in the reactivation of the existing buildings and the construction of the garden stair entirely in timber, a carbon negative material. The only element of the new structure which is not timber is the concrete raft foundations.
We had to discount other more sustainable foundation materials because of the sensitivities of building in a graveyard. Screw piles, which could have been re-used, could damage the archaeology, and rubble filled trenches would not have distributed point loads evenly.
Of course, the concrete foundations could be re-used at a later date, either in situ or broken up and used for aggregate.
How did you get the job?
Sites with existing buildings on them bring their own challenges and opportunities; [a client] would be looking for an architect to engage with that process.
Our client for this project held a design competition which was very much focused on responding to the existing buildings. In fact, Rob held an exhibition about retrofit as a cultural catalyst in 2012, when he was director of the Bristol Architecture Centre.