Cambridge Central Mosque, Mill Road, Cambridge

Introduction

The design of the new mosque in Cambridge, by Marks Barfield Architects, is based on the concept of ‘a calm oasis for contemplation, under a grove of trees’, inspired by the image of the garden of paradise. This is expressed in the timber structure, a series of tree-like timber columns that rise into flowing fan vaults to merge with a geometric timber ceiling. These timber forms were inspired by both Islamic and British sacred traditions, from the 16th century stone vaulting of nearby King’s College Chapel to the repetitive arches of the Cordoba mosque in Spain.

Marks Barfield Architects won a 2009 competition to design the building and, together with clients and patrons, researched the question of what a British mosque might look like in the 21st century and how this might be achieved and integrated with a minimal carbon footprint.

Their research revealed that for centuries and throughout the world mosques have adapted to local cultural and climatic conditions and adopted local vernacular building materials and technologies. The new building would be of its place and time, strongly contemporary while merging both Muslim and non-Muslim forms.

The mosque stands amid terraced streets on the site of a redundant warehouse. The deep plan allows the mosque to be set back from the street so that worshippers and visitors move in a procession of spaces from the outside world to the sacred space of the prayer hall. Entering from the street, they walk through a public Islamic garden to reach the main entrance, a deep portico supported by the first row of glulam structural ‘trees’.

A glazed screen leads through to a stone-paved atrium, also supported by glulam structural trees and with a timber-lined education centre and a cafe leading off to the sides. Orientated towards Mecca, the prayer hall itself is supported by four rows of glulam structural trees and the walls are lined with an oak panelled dado, with upper walls revealing the cross-laminated timber (CLT) structure of the external walls. Daylight filters down from glazed oculi positioned directly above each glulam tree.

The mosque is a spiritual and cultural centre for Muslims; it is also nondenominational, inclusive, open and welcoming to the whole community, intended to be a meeting place and a cultural bridge where modernity and innovation meet timeless sacred principles.

The use of timber

The defining visual feature of the mosque is its timber structure, and the natural grain, texture and colour of timber impart a warm and calming feel to the internal spaces and the portico. But in this context the use of a sustainable material was especially important. As the architect states: ‘Trees absorb and encapsulate CO2 as they grow, have low embodied energy and are a renewable resource. As a religious building that emphasises spiritual belief in humanity’s role as a humble and responsible custodian of creation, the mosque has been designed with a minimal carbon footprint.’

The glulam tree columns and ceiling structures, and the CLT wall and floor structures are PEFC-rated German spruce. Doors, wall panels, bookshelves, shoe racks and ventilation grilles are all of FSC-rated European oak. The prayer hall doors are inlaid with marquetry in Islamic patterns, made of FSC-rated European oak and FSC-rated mahogany.

The underlying geometry of the timber structure is based on ‘The Breath of the Compassionate’, a historic Islamic pattern of squares and diagonals formed into repeating star octagons. The glulam structural trees in plan are based on these geometric patterns, joined to form a structural grid, with the centres of alternate octagons as the structural columns or ‘trunks’, which rise and curve outwards into a vaulted three-dimensional form. There are 30 glulam structural trees, and their repetitive nature is designed to create an overall impression of calm, stillness, stability, quiet and focus, combined with a strong sense of place.

The glulam tree structure

David Lockett, structural engineer and partner at Price & Myers, describes the tree structure: ‘Each timber tree consists of sixteen individual doubly curved glulam ‘branches’ that come together to form an octagonal ‘trunk’. Arranged in a regular 8.1 metre grid, these trees are the columns and their canopies are the primary and secondary structure that provide support to the roof.

The primary branches work as a set of compression arches, restrained by a steel star just above the top of the trunk, to transfer load to the ground floor slab. They are interwoven with twelve secondary branches to create the geometrical arrangement that frame the skylights and provide support to the dome.

The branches utilise a combination of traditional halving joints and steel screws hidden behind timber plugs. The trunk is connected to the ground floor slab with a steel shoe.’

The geometric patterns underlying the structural forms were hand-drawn by Keith Critchlow and then translated via Rhino into 3D CAD models by Marks Barfield Architects before being sent to Blumer Lehmann in Gossau, Switzerland, for fabrication.

The repetitive nature of the glulam structural trees meant that, in most cases, the glulam components could be standardised. There are 2746 pieces forming the vaulted structure, with 145 different types, constructed by 5-axis milling from 23 different blank types. After fabrication, the curved glulam elements were pre-assembled at the Blumer-Lehmann factory, secured to the tops of the 16 glulam column ‘trunks’, and transported to site.

The superstructure

The superstructure of the mosque consists of prefabricated cross-laminated timber (CLT) panels, with the 70mm CLT internal faces exposed as internal wall and ceiling surfaces, all treated with a fire retardant finish. The CLT flat roof construction is supported by glulam joists which transfer load to the structural glulam tree canopy. Glulam members also provide trimming to skylights. The CLT roof plate acts as a diaphragm to transfer lateral loads to the external walls.

The junctions between exposed internal cassette panels are designed with a 6mm shadow gap so that any seasonal expansion/contraction of the panel would not be overly visible. To avoid damage by splintering, a 2mm diagonal chamfer was introduced to the exposed 90 degree corners of the CLT panels. Likewise the junctions between exposed wall panels and ceiling panels are designed with a deep recess detail to ensure that any misalignment is hidden in shadow.

Sustainability

Externally, the walls are clad with brick tiles patterned in traditional Kufic styles. The wall and roof construction, combined with high levels of insulation and air tightness, ensured ultra-low U values.

Air source heat pumps are used for underfloor heating/cooling which also includes an innovative system of direct hot water heating via buffer tanks. There is no gas used on site, so there are zero carbon emissions.

The building is part powered by a photovoltaic array on the roof, which is sufficient to cover all of the hot water used in the building, all of the cooling and 13% of the heating. Rainwater is harvested for flushing WCs and irrigation. The building form and fabric specification ensure that all public areas are naturally lit during daylight hours and naturally ventilated throughout the year – even during periods of peak occupancy.

Awards

AJ Architecture Awards 2019 – Best Community & Faith Project
Wood Awards 2019 – Structural Award
Wood Awards 2019 – Education and Public Sector Award
Structural Timber Awards 2019 – Winner of Winners and Project of the Year
British Construction Industry Awards 2019 – Best Culture & Leisure Project
RTPI Awards 2019 – Planning Excellence
Offsite Awards 2019 – Best Use of Timber Technology

Completion Date:

April 2019

Building Type:

Mosque

Location:

Mill Road, Cambridge

Architect:

Marks Barfield Architects

Structural Engineer:

Price & Myers

Building Services and Sustainability Consultant:

Skelly & Couch

Main Contractor:

Gilbert Ash

Project Manager:

Bidwells

Timber Structure Engineer, Fabricator and Installer:

Blumer Lehmann, Switzerland

Timber Supplier:

Mayr-Melnhof Holz Reuthe GmbH, Austria

Joinery:

The Deluxe Group, Portadown NI

Timber Elements:

structure, roof, walls, floors, doors, wall panels, bookshelves

Timber Species:

PEFC-certified European spruce, FSC-certified European oak, FSC-certified mahogany

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