Housing in Stoke Newington, designed by Groupwork

Words
Amin Taha
Photos
Timothy Soar

Barrett’s Grove in Stoke Newington is an archetypal London street of two-storey Victorian brick terraced houses interrupted by a diverse run of buildings: a rubble-walled church, two detached apartment buildings from the Edwardian era and the 1980s, and a London County Council school. A new block of six flats with a tall red gable facing the street, designed by architect Groupwork (formerly Amin Taha Architects), sits amongst these stand-alone structures. It shows a conscious attempt to complete this eclectic parade by marrying the form and scale of its larger neighbours to a recognisably domestic character.

“The building aims to sit sympathetically within the streetscape and its roofline”, says Amin Taha. “Though it has a carefully proportioned balance of openings within the brick facade, it aims to be idiosyncratic, with layers of detail that are closer to the Arts & Crafts desire for the organic than the neoclassical order of Georgian architecture”. Brick clads both walls and the pitched roof. Its double-stacking and open bond adds texture, and reveals that the envelope is not loadbearing. Large window and door openings exaggerate the slenderness of the building’s form. Steel balconies clad in woven wicker are hung from every other aperture, further softening the building’s material expression.

Once inside, the building’s structural truth is revealed, as cross-laminated timber (CLT) walls, floors and roof are left exposed, with visible construction joints and panel edges left undisguised, disclosing the method of assembly. Removing the need for paint, plasterboard, suspended ceilings or skirtings gave significant savings in construction costs and time on site, as well as reducing the building’s embodied carbon by 20 per cent. The CLT floors span up to six metres, and the walls rest on a concrete basement.

The CLT superstructure was overclad with insulation, a vapour barrier and protective sheeting, and the self-supporting brick rainscreen, which is decoupled from the rest of the building to allow it to expand and contract separately. Keen to avoid the cost-driven use of a one-brick-thick rainscreen in stretcher bond, the architects demonstrated that removing a quarter of the bricks would generate greater savings while improving the building’s architectural quality. The use of double-stacked bricks increases the apparent scale of the module, adding intriguing ambiguity to the facade.

The efficient design of structure and skin gives the building a distinctive identity, but with construction costs that match other mid-market speculative housing in the area. Close attention to cost-efficiency allowed Groupwork to use custom-made elements, throughout the project, from built-in CLT seating in the porch to leather-wrapped handrails and open-faced bronze-patinated latches set into the solid timber doors.

Viewpoint – Amin Taha:

“Our apartment building on Barrett’s Grove, like its context of Edwardian and Victorian houses, was a speculative project. One half of the street is an intact terrace of two-storey dwellings with pitched roofs, the other a mix of standalone purpose-built blocks, including the neighbouring Victorian apartments in the shape of a large urban villa. The forms might be repetitive, but there are idiosyncrasies in the detailing of the bay windows and columns and capitals in the door surrounds, whose variety lends identity and speaks of the domestic.

Most developers of speculative housing today are fearful of deviating from the norm because, first, their experience is that the norm will always sell and any idiosyncrasy could reduce the potential market, and second, they are concerned the idiosyncratic will increase cost.

You can persuade them on the cost easily enough if you can demonstrate the savings through testing. In the case of Barrett’s Grove, the use of cross-laminated timber for the superstructure saved time on site, and we worked with acoustic and fire engineers to show that it could be left exposed internally, saving on plasterboard linings. Suspended floors provide the necessary acoustical build-up between flats, and by integrating services within them, we could make further savings on electrical layouts, radiators, finishes and so on, saving around 15 per cent of construction cost.

At the cheaper end of the housing spectrum, it’s challenging to achieve good results both internally and on the street. To do that economically, the building needs to be investigated from first principles: what are we making this from? Too many architects will simply draw two lines for the wall structure – one representing the ‘facade’ the other the interior – leaving a blank space in between for the structural engineer and quantity surveyor to fill in. Time is spent rationalising the plan to meet efficiency criteria while adjusting differently patterned and coloured elevations. If, on the other hand, these ‘lines’ are integrated with the structure to provide the finishes they can tell an architectonic story and in this way become the expression of the architecture. A vocabulary of materials, with endless visual, tactile and structural qualities, can generate a literate or even poetic architecture.

Today, many buildings are essentially dictated by quantity surveyors, because architects submit to their unarguable cost plans split into a series of categories: substructure, superstructure, envelope, m&e, finishes, landscape. The model doesn’t recognise that structure, envelope and internal finishes can be a single element, so architects need to do their own research, and pull in the suppliers and subcontractors to demonstrate viability. It’s not easy for quantity surveyors to restructure their standard cost plans, but once a guaranteed price has come in from the horse’s mouth its harder still for them to argue against it.

Developers are certainly happy to achieve the savings that can be had by not settling for details straight out of the book, but the second issue – of saleability – remains. To take a risk on 200 apartments can be a tall order, but the six flats at Barrett’s Grove represent a small part of the client’s overall portfolio, and we were able to persuade them that, despite their agent’s initial scepticism about exposed internal timber, the CLT could be plastered, painted or whitewashed as a fallback. In the event, three flats sold immediately after the first viewings, and the agent increased the prices of the remainder.

The developer’s expectation was that the flats would achieve a little less than the market value for new-build developments nearby, so we worked to a very strict cost calculation to allow the necessary margin. By taking greater responsibility for coordinating structure, services and costs – areas increasingly left to other consultants or design & build contractors – we built to budget, and without value-engineering out the idiosyncratic details.

Barrett’s Grove was completed at a cost that housing associations could afford, and in fact exceeded the developer’s expectations by about 25 per cent. Because it isn’t the generic market product and perhaps offers a little more charm on a tight budget, conversely buyers actually seem willing to pay more for it.”

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