Iroko (Coin Street) Housing

Iroko [Coin Street] Housing


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image source: http://www.haworthtompkins.com/coinst/index.html

General outline

KEY INFO
ssoa.jpg
Location South Bank, London
Number of Units 59
Type Social, Co-operative
Completion 2001
Architect Haworth Tompkins
Cost £14.5 million

This example is relevant to the studio if we are to understand how a co-operative relatively large scheme can work in an urban setting. This scheme provides successful affordable family housing in an urban context and is able to incorporate a substantial amount of external private and communal space.

Iroko housing at Coin Street is a mixed tenure housing development in South Bank, London, developed by the Coin Street Community Builders (CSCB), the not-for-profit community housing developer of London's South Bank. Haworth Tompkins designed the scheme as part affordable rented and part co-operative with private or shared ownership. It was completed in 2001 and opened by Ken Livingstone in March 2002.

The site is in a difficult location with the north side flanked by large office blocks, largely blocking the river, the south is bordered by the busy Stamford Street, to the east is a modest housing project (the first by CSCB), and to the west is a site earmarked for a sports centre and higher density housing, also by CSCB.

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The architects left the number of units to be provided and the type and arrangement of these units upto the entrants. The result has been 59 homes, of which 32 are five-bedroom houses, 6 are three-bedroom maisonettes and 21 are one and two-bedroom maisonettes and flats including one designed for a wheelchair user. This provides 334 habitable rooms per hectare, which is an increase of 59% from Lambeth's planning guideline of 210 rooms per hectare. The ground level of the scheme incorporates two corner shops and there is a limited provision of twenty-one resident car parking spaces. The basement level car park also has 260 commercial spaces which provide subsidies for the affordable housing above.


History

Initial designs for the site had been for a design by Richard Rogers for a 16-storey office tower. However, Iain Tuckett and other local residents, physically stopped the public inquiry into the Rogers scheme in the early 1980s because it ignored the community-based approach. The megastructure was rejected and Coin Street Community Builders, led by Mr Tuckett, were given the site.

A competition was held by the Coin Street Community Builders to design their fourth and largest housing development. The 0.87 hectare brownfield site was an entire urban block behind the London Weekend Television Centre. The site had previously been occupied by six-storey high warehouses and after being cleared was temporarily used as a car park.

From an initial list of nine young practices, six were invited for an interview and four were selected to prepare outline designs. Haworth Tompkins Architects, a practice with no previous social housing experience, was unanimously chosen as the winner, as its central courtyard scheme best addressed the challenges and opportunities of the site.


Brief

To fully exploit the site's potential of large family homes, the architects designed terraced housing in a perimeter layout, providing not only for large households but also smaller ones. All homes have a private open space, this being balconies on upper levels and gardens on the ground floor.

The arrangement is such that the houses site on three sides of an open courtyard, which houses a large communal area separated into designated play areas. The fourth side of the square is home to the Stamford Street Neighbourhood Centre. The elevations address the context with five-bed terraced houses being four storeys high, onto Coin street and Cornwall road, with the attic rooms set back to offer a generous terrace overlooking the courtyard.

The street elevations are crisp and robust with the use of orange/ red brick (perhaps to relate to that of the Oxo building) with deeply set windows. Pre-weathered zinc cladding is used at upper levels where the elevation steps back. In contrast, the courtyard elevations are softer with the use of materials which can weather and mature with the landscaping. Framing is concrete and is exposed, to an extent, with edges of slabs and faces of columns exposed. The infill cladding is vitex cofassus, a naturally durable hardwood, which requires no preservative treatment or applied finishes, thus reducing maintenance costs. The same timber has been used for horizontal sunshades and balcony decking.

Cost

The total cost of the build was £14.5m. The unit construction cost of housing was £1018 per square metre and is 36–104% higher than average social housing schemes, as a result of high density and quality specification. The costs of the underground car park, at £450 per sqm gifa, equating to £12,200 a space, are at the lower end of the cost scale (typically £370-570/m2). This results from the site already being part excavated, and from the limited requirement for retaining walls to one side of the site only.

Like all Coin Street's housing, the housing is run as a co-operative. The homes are leased to Iroko Housing Co-operative, an independent registered social landlord, which lets the properties in turn to its tenant members. The homes are let at affordable rents (from £76 a week including service charge for a one-bedroom flat to £123 per week for a five-bedroom house) to individuals and families in housing need who can show good reason to live in the area. Successful applicants must also be committed to taking an active part in the general running of the co-op. Now the housing is occupied, full responsibility for its management has passed to the new co-op tenant members. All have completed an initial training programme of 11 three-hour sessions. An elected management committee of 15 people is responsible for the day-to-day running of the co-op between quarterly general meetings of all tenant members.

Form and Layout

The layout of the scheme is based on a quadrangle format with a communal space in the centre. The space, measuring 57 x 60m acts as a communal amenity including children's play areas. The courtyard space is careful divided for different uses by low concrete walls and level changes. With the large child population here the courtyard provides ample playing space for them. All flats and maisonettes have large balconies and every bedroom overlooking the courtyard has a balcony. The balconies are divided by vertical translucent screens for privacy.

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The communal courtyard split into defined areas

The ground floor houses have a private buffer zone in the form of a raised pavement area separated from the public pavement by timber and stainless steel bin enclosures and railings. Each house also has a gated porch off the street with a large cupboard to store items such as buggies and online shopping deliveries. On the two side streets are large four-storey houses with two-storey maisonettes above. Both of these are reached via glazed staircases.

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Ground floor entrances with a secured porch and bin enclosures

The car park in the basement is mechanically ventilated, supplemented by natural ventilation through the entrance ramp. The car park has not been allowed to disrupt the street elevations and house entrances, as they are ventilated by louvres discreetly located adjacent to the pedestrian entrances to the car park. Exhaust air is discharged at roof level five storeys above.

Technology and Construction

Being a brownfield site many of the concrete pad foundations were retained from the former warehouses. Designed on low energy and design principles, passive solar panels are incorporated, providing free hot water to residents for most of the summer and reducing the demand on the heating system for the rest of the year. High efficiency gas fired condensing boilers, with a heat efficiency of 90%, heat recovery and ventilation systems, low-emissivity double glazing and a high degree of air tightness reduce energy consumption and bills by 30% whilst providing better air quality.

The frame of the housing comprises reinforced concrete supported on columns in the party walls with dense concrete blockwork between. Four-hour fire separation between car park and housing was achieved with lightweight aggregate concrete and by widening the supporting columns. The structural concrete slab with a 125 mm floating screed insulation provides acoustic separation between the car park and the dwellings. In the central courtyard, the ground floor slab has been designed to support 650 mm deep planters. Everdure Caltite, a waterproof additive, was included in the concrete mix, making waterproof membranes unnecessary.


See also

Architect's Journal, volume 215, no. 23, June 13, 2002, p.18-42
Architect's Journal, volume 206, no. 5, July 31/ August 7, 1997, p.8-9
RIBA Journal, volume 104, no. 8, August 1997, p.21-21
Building, volume 267, no.8225 (10), March 15, 2002, p.76-81
Architecture Today, no. 127, April 2002, p.22-33


External links

http://www.coinstreet.org/iroko.aspx
http://www.haworthtompkins.com/coinst/index.html
http://www.building.co.uk/story.asp?sectioncode=113&storycode=1016354&c=1
http://www.telegraph.co.uk/property/newhomes/3295868/Designer-buildings-for-a-new-model-community.html
http://pdfserve.informaworld.com/668055_731467345_714022895.pdf (for a detailed analysis of the venilation strategies used)
http://housingprototypes.org/project?File_No=GB014
http://architecturelab.net/2008/05/26/coin-street-social-housing-iroko-by-haworth-tompkins/


Content Reference Note

All drawings, diagrams, information and main image are taken from journals mentioned in the see also section and the external links. All other photographs are the author's own.

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