Arcadia Nursery, Edinburgh, City of Edinburgh

Introduction

Arcadia Nursery was created to provide early-years education for children of university staff, students and the general public and caters for up to 113 children ranging in age from six weeks to five years. The new nursery brings together two existing university nurseries, on two separate sites in the city, into a single purpose-built building with a generous outdoor play area, sited next to the university campus on the southern edge of Edinburgh.

The nursery managers were keen to work with the ‘free-play’ concept of nursery education, an approach that aims to develop children’s confidence, independence and creativity by allowing age groups to mix, by encouraging children to choose which activities they would like to participate in and whether they would like to be inside or outside, rather than having their day dictated to them. The layout reflects these ideas, while ensuring that the children are safe and easily supervised.

The site chosen for the new nursery was well covered with mature trees and the layout reflects the architect’s desire to retain as many healthy trees as possible, in order to create a sheltered and protected garden environment for the children. To avoid disturbance to tree roots, the building was raised above ground level and had to be a lightweight structure so that only short pile foundations were required. It also had to be constructed within a relatively restricted site compound. But above all it was important to design a low-energy sustainable building which would provide a healthy atmosphere for the children. Timber, and in particular the use of a cross-laminated timber structure, answered many of these needs; it provided, in the architect’s words: ‘the perfect combination of creating a warm, tactile interior, while also using a natural, sustainable product that could structurally achieve the clear roof volumes required to ensure the mezzanine spaces were not compromised.’

Timber not only forms the main structure, it is used throughout the nursery. The external walls are clad with horizontal and vertical boards of Siberian larch together with panels of copper sheet with vertical seams. The building fabric is insulated with breathable wood fibre insulation. Inside the nursery, the timber walls, ceilings and structure are exposed, with internal fittings and furniture also made of timber. In the garden timber is extensively for decks, walkways, fences and play features.

The nursery design

The architect worked with the nursery managers to identify issues with the existing nursery buildings; they included disconnected spaces, lack of connection to outdoors, no opportunities for the children to come together in one space, difficultly settling children when changing age groups, together with small and remote rooms. The solution was to consider the new nursery as a free-flowing series of interconnected spaces that could be opened-up or closed-off to suit the activities of the day, with the focus not solely being one playroom per age group, but a series of additional spaces which are all connected at the heart of the building with a flexible welcome and circulation space, used for many functions including dining and coat storage.

The building has three playrooms, one for each age group, each of which is clearly identifiable from the outside as a pitched roof pavilion with a sloping glazed roof at the top, creating a sense of belonging and ownership for each age group. Four stout timber columns support the overhanging porch which forms the entrance to the nursery. The reception leads into the welcome and circulation space, with an open kitchen at the rear to allow children to watch the cooks preparing food and with a smaller children-sized kitchen forming the divide between the two spaces.

This central space connects the three large playrooms for age groups six weeks to two, two-to-three and three-to-five, with associated baby change and WCs incorporated within each playroom.

The babies’ playroom is a cosy, domestic height room with an enclosed sleeping area on the ground floor; the upper storey above accommodates a staff room which overlooks the garden, office and family rooms, with an additional space for use by small groups of children participating in activities such as music, reading and IT.

A shared space for joint activities links the babies’ playroom to the playroom for two to three-year old children, and this in turn is linked by another shared space to the playroom for three-to-five year old children, so that the playrooms flow into the other as a series of spaces. The whole area can be opened up to suit the day’s activities, and children can easily visit their friends and siblings in other years. The two playrooms for older children have mezzanine spaces for quieter times.

All the playrooms have large glazed doors which open the space out into the garden, enabling children to move freely in and out, with a covered terrace providing a transition between inside and outside. Part of the garden is enclosed, with equipment for open-ended creative play. A gate leads to a larger landscaped area for older children with a timber walkway meandering through trees, a rope bridge, log ladders and a sandpit. Finally there is a meadow zone where wild flowers, birds and insects are encouraged.

The structure

Tim Hetherington, director of AED, describes the structure:

'The nursery has a hybrid structure consisting of glulam, cross-laminated timber, prefabricated timber cassettes, local steel members and frames and steel-reinforced connections where required, all supported on a predominantly cast in-situ suspended reinforced concrete slab, spanning between ground beams, in turn supported on driven steel piles. Parts of the substructure were constructed in thin precast concrete units supported on special ground beams in order to avoid damaging, and allow growth room for, the shallow root systems of retained trees. The walls and roofs are formed of storey-height panels of cross-laminated timber and locally, glulam. Glulam columns support the perimeter in two areas. Steel posts and beams are used minimally internally to cater for unique load or spatial requirements.

The three zones of the building are defined by their trapezoidal pyramid roofs, each one distinguished by its size and shape. Each roof is constructed of cross-laminated timber panels, supported on a continuous glulam ring beam to contain thrust from the roof form.

The tallest roof, which encloses two-storeys with the playroom for under-two children on the ground floor, has an intermediate floor of prefabricated timber cassettes with perforated acoustic panels forming the lower face of the cassette panel. Several dormers pierce the roof form, complicating the structural arrangement. Two steel frames also provide lateral stability here.

In contrast the internal volumes of the other two playrooms reflect the shape of the open roof above; the cross-laminated timber panels which form the slopes of the roof are clad with slatted timber panels to deaden sound and and create a warm aesthetic; they rise to a large sloping roof light. A mezzanine fits into each of these playrooms; its walls and floor, together with the staircase, are entirely formed of cross-laminated timber panels. The larger of these two roofs also has an additional glulam slab forming the sloping perimeter edge to control spread.

The welcome/circulation/office space is single storey, with a flat roof structure of exposed glulam beams supporting cross-laminated timber panels, having additional soffits of perforated acoustic board to achieve acoustic deadening. A continuous sloping roof light runs along one side of this roof. The composite timber windows are painted internally, with grey aluminium external frames.'

Tight construction tolerances had to be maintained and coordinated between the concrete base build and the off-site cross-laminated timber works, including the size and position of the lift pit and shaft within the building, to ensure successful placement of all elements on site. Moisture ingress was a concern during a wintertime build in Scotland, but this was successfully controlled on site through the use of temporary coverings. 

Sustainability

The nursery has been designed to be a very low-energy building. It is connected to the central University CHP network and therefore no heating plant was needed. In addition the building uses no refrigerants, no mechanical cooling or ventilation and highly efficient lighting has been installed. The specification of all materials was carefully considered, with materials being chosen that are renewable, have low embodied energy and a minimal carbon footprint. The design stage BREEAM assessment achieved a high score of 82.2 per cent, with material and pollution sections achieving a 100 per cent score.

Renewable FSC certified timber is used extensively throughout to create the structure, including internal walls, floors and ceilings. Wood fibre insulation is used to line all walls and roofs, creating a vapour open, breathable construction while also making use of a waste product. The use of a cross-laminated timber structure involves very little site waste as the whole envelope was delivered to site factory cut and prefabricated; the Stora Enso Wood Products factory itself is powered by its own waste products.

The main building materials of timber and copper can be recycled at the end of the life of the building. No site water was required to construct the building as no wet trades were used. Water use is kept to a minimum with water saving devices installed throughout the building.

Completion Date:

August 2014

Year Published:

March 2016

Building type:

Nursery

Location:

Edinburgh

Client:

University of Edinburgh

Architect:

Malcolm Fraser Architects

Structural engineer:

AED

Timber engineer and structural frame contractor:

Eurban Ltd

Main Contractor:

Balfour Beatty

Joinery:

MK Timber

Timber Suppliers:

Stora Enso, Lignatur, Lignotrend, Russwood, Natural Building Technologies

Timber elements:

wall, floor and roofstructure, mezzanines, staircases, internal and external cladding, furniture and fittings

Timber species:

Austrian spruce, Siberian larch, Scottish larch

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