St. John’s Music Pavilion, Lacey Green, Buckinghamshire

Introduction

The new music pavilion at St. John’s, a small state primary school in the Buckinghamshire village of Lacey Green, is an elegant and award-winning timber structure which was built as a co-operative venture with the school, local people and local workshops. It was designed by the architect Clementine Blakemore for her final design project at the Royal College of Art, as a model of how to achieve a small-scale educational building through local collaboration in the absence of conventional educational funding. As well as involving the community, the building was designed as an example of low energy consumption, natural light and renewable materials; timber was the clear choice for structure and cladding.

Local residents raised funds for the building, the structural timber was donated and fabricated at a local workshop and much of the construction was carried out by students and local volunteers, supervised by Blakemore.

The school is on the outskirts of the village and the new building is on the northern edge of its site, overlooking farmland. It has a simple yet striking silhouette created by a roof of two steep double pitches, one larger than the other. The form was inspired, explains Blakemore, by the geometry of the painter Agnes Martin while also referencing local agricultural buildings. Both roof and side walls are clad with a continuous wrap of black-stained, feather-edged timber boarding. The two front gables of the building face the existing school buildings and are clad with a rainscreen of vertical larch boards which will weather to a silvery grey. Inset within the larger gable wall is a glazed bi-folding door which extends across the width of the gable and can be fully opened to allow the children to work outdoors in fine weather. The two rear gable walls are clad with semi-translucent polycarbonate panels which transmit even, northern light into the interior.

The timber structure

The building aimed to be an example of the use of local materials to reduce embodied energy. The structure is of Norway spruce, grown, felled and milled at Hooke Park, a forest in West Dorset that is owned and managed by the Architectural Association School of Architecture. The green spruce timbers were prototyped, fabricated and CNC-milled by a local workshop, Grysmdyke Farm, located in the same village as the school. The European larch cladding was homegrown and locally sourced from Hampshire.

As if to reflect the ethos of collaboration which inspired the project, the timber structure is an innovative reciprocal frame, each member resting on the adjacent one to create an interlocking lattice. Inside the music room the structure is clearly visible, lined with butt-jointed spruce boards to create a warm and inviting enclosure. The reciprocal frame extends across the two polycarbonate-glazed gables and when the room is lit at night its outline is clearly visible from outside.

Steve Webb, director of Webb Yates Engineers, worked on the structural design with the architect and together they developed a reciprocal frame structure for both walls and roof, using relatively short lengths of timber and connected so that moments are transferred from one short length to another. The roof is untied and the thrust from the roof is transferred to the front and rear gable frame by the butt-jointed spruce boards – which together act as a diaphragm. The front gable is a full portal frame with moment-connected steel splices at junctions.

The structure is formed of 171 tapered spruce members, CNC-milled and hand assembled to create an interlocking lattice. Each lattice member is tapered, increasing in width to 200mm at the centre where the mortise joint is located, and decreasing to 100mm at the ends where the tenons are located, so that each element is lighter and visually more elegant. When assembled, the flush side faces outwards while the pitch of the tapers face inwards; this allows the butt-jointed spruce boards and external cladding elements to be fixed easily to the frame.

The construction process

For the first phase, the timber structure was assembled as part of a two-week AA Visiting School workshop and completed over the next five months by the architect with the support of the school’s caretaker and volunteers. It was used as an outdoor pavilion for informal music performances during the summer term.

After fundraising, the second phase proceeded in 2017 with Timber Workshop as the main contractor. The structure was cleaned to remove the result of exposure and then enclosed with insulated stud walls and roof, clad with a rainscreen of feather-edged larch weather-boards. The front gables were enclosed with a new stud wall incorporating the bi-folding glazed doors and clad with the rainscreen of vertical rough-sawn larch boards. The end gables were clad with polycarbonate sheet. The room was fitted with a new timber floor and storage benches were installed at the perimeter of the room. Wycombe Council provided CIL funding to enable two local craftspeople to contribute to the project. Design & Making designed bespoke storage and seating based on the rich local furniture-making heritage and Karina Thomas designed a series of woven lambswool panels to contribute to the thermal insulation and acoustic performance of the interior.

Awards

Wood Awards 2019 – Small Project Shortlist
AJ Small Projects Award 2020 – Shortlist
Sustain RCA Award 2015 for Visionary Process – Winner

Completion Date:

March 2019

Building Type:

School

Location:

Lacey Green, Buckinghamshire

Architect:

Clementine Blakemore Architects

Structural Engineer:

Webb Yates Engineers

Main Contractor:

Phase Two, Timber Workshop

Timber Supplier:

Hooke Park, West Dorset

Timber Elements:

structure, wall and roof cladding, floor

Timber Species:

Norway spruce (certified as Grown in Britain Scheme), FSC- and PEFC- certified WISA spruce plywood, UK grown larch cladding

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