The timber-framed structure adjacent to Taunton School’s Grade II-listed Main Building is flexibly designed for use also as an event space by both the school and the local community

The new dining and catering facility, designed by Wotton Donoghue Architects (WDA), functions as a dual-use hall that can be subdivided using a 4m-high glazed acoustic screen, creating two separate dining halls for the junior and senior schools, which together seat up to 440 students. These spaces, each with in-built IT and AV facilities, can also be used for school functions and lectures and for wider community events such as weddings.

The timber-framed structure sits between two existing buildings, directly behind the school’s Grade II-listed Main Building, with a fully-glazed façade facing onto Densham Green to the north.

The dining hall is the first completed element of the masterplan, which WDA was commissioned to develop in 2017 for the school’s Staplegrove Road campus and replaces a tired former sixth form study space and overspill service yard.

Its structure is formed by a lightweight glu-lam birch frame, with its plan and structural grid aligned with the architectural axis established by the Main Building’s central stair tower.

The use of sustainable, self-finished materials is intended to create a visually warm open-plan space with good acoustics. The large expanses of floor-to-ceiling glazing to the north helps optimise daylight penetration, supplemented by rooflights and clerestory glazing on two sides, while turrets set at roof level assist in passive ventilation.

Architect’s view

WDA were delighted to collaborate with the school to deliver this important new social space located at the heart of their campus, which now provides a real focus for social activity. Even in these current times it is showing its flexibility by providing the school with a dedicated onsite lateral flow testing centre.

The building form was derived from the axis established by the existing stair tower. The building’s structural grid was centered around this feature to offer the opportunity for the new building to showcase the restored heritage features of the listed building, while creating a strong architectural rhythm expressed internally by the glu-laminated frame. WDA collaborated with IESIS Structures, which developed the timber frame design principles pre-tender and subsequently progressed for construction by timber frame specialist Constructional Timber. The use of sustainably sourced timber for the frame enabled the design to achieve long-span, open-plan space in both directions, with tapered rafters aligned on the underside, set above a perimeter glazed clerestory, allowing the shallow roof to seemingly float over the vaulted dining hall interior.

WDA worked closely with Constructional Timber on the design and detailing of the frame, which adopts ‘concealed’ joints at the connections, allowing the frame to slot together on site relatively easily, with only one occasion where the largest timber mallet I have seen was used to ‘tap’ the beam into place!

The roof’s coffered timber frame pattern was carefully transposed onto the internal floor finishes below, where interlocking timber planks are arranged in a matching pattern to create a visually coherent interior. The choice of CLT and glu-lam frame brings warmth to the building’s interior and with a translucent fire-resistant coating enables the building’s frame to be expressed as the defining feature of the construction.

Chris Donoghue, partner, Wotton Donoghue Architects

Client’s view

When Taunton School set out to construct the new whole school dining room and kitchen in the summer of 2019, we never in a million years expected what was to face the project team just six months later. With lockdown imposed and massive uncertainty around when works could recommence and ultimately complete the team at Wotton Donoghue Architects, QSPM and C G Fry pulled together in a supreme effort to formulate a plan. Works were suspended on site for five weeks but when they restarted there was a safe and deliverable completion programme, ready to go. The following three months saw an incredible concerted effort by the whole team to ensure the facility was completed and able to deliver meals when school returned at the start of September. With days to spare the project was handed over and opened with 450 breakfasts served to returning boarders. In normal times the facility will serve over 2,500 cooked meals every day.

The whole project, from inception to completion, has been professionally designed, procured, managed and delivered by all concerned and the success of this massively important scheme for Taunton School, which will benefit generations of students for years to come.

Taunton School is hugely grateful to the whole project team for helping us to achieve this significant milestone in our Strategic Estates Master Plan.

Terry Harris, estates manager, Taunton School

 

 

Source: Architects Journal

 

James Jones Timber Systems Division forms partnership with Ockwells to offer stairwell protection systems to UK housebuilders.

James Jones & Sons’ Timber Systems Division, the maker of the UK’s market-leading I-Joist system, JJI-Joists, has entered into a partnership with specialist building and protection materials manufacturer Ockwells, which will see it recommending Ockwells’ Stairwell Hatch System to all JJI-Joist customers in the future.

After months of research in to available stairwell protection systems, James Jones’ Timber Systems Division has opted to recommend the Ockwells temporary site protection system because of its superior build quality, flexibility in applications of use and the simplicity of installing the system to house building and construction sites without adaptation to existing build practices.

Independently tested and verified, the Ockwells Stairwell Hatch System is designed to provide full cover platforms over the stairwell openings in various combinations to suit all build sites and conditions. Once installed, the system prevents falls through large stairwell opening whilst giving access for operatives and materials.

The system is designed to be lightweight for handling and ease of use on site and it allows safe and fixed access to a ladder prior to a staircase being fitted. The system comprises three parts – hinged and framed glass reinforced plastic (GRP), a steel ladder plate for securing a ladder and a steel box sections adjustable telescopic joist, which allows openings next to party walls to be accommodated by the system.

Speaking of the joint venture Mark Tilston, Systems Development Manager for James Jones’ Timber Systems Division, said: “Stairwell protection systems is something that our business has been investigating and researching for a while now and we are delighted to have found in Ockwells a partner that provides a robust and safe solution for all JJI-Joist distributors and end users.

“The Stairwell Hatch System is well designed, solidly manufactured and above all, it works. They have also produced a simple step by step installation guide which gives you clear advice on many applications. The system allows you to continue using crash deck systems and bird cage platforms which is unique. Their product has been independently tested to give you confidence.”

John Gray, Sales Director at Ockwells, said: “Ockwells are delighted to be partnering with James Jones’ in this new and exciting development. Having spent a great deal of time developing the Stairwell Hatch System it’s great to see that our customers are seeing the benefits from our safety system.

“As well as providing a safe working platform over stairwell openings, the Stairwell Hatch System is also very cost-effective, being reusable means that the initial investment is quickly recouped when compared to the cost of using sacrificial joists, which can run into hundreds of pounds per plot. We believe that the combined expertise of James Jones’ and Ockwells will result in significant health and safety, and cost benefits to James Jones’ customers.”

www.jamesjones.co.uk

Premier Guarantee Technical Standards Manager, John Gilbert, provides technical guidance on the treatment of Cross Laminated Timber. The recent interest in ‘modular buildings’ as a solution to the housing crisis and current skills shortage, has brought forward the potential use of ‘CLT’ (Cross Laminated Timber) as a structural panel to produce wall panels or indeed modular pods.

A number of CLT products have third party product approval for the use as a structural plank for construction uses. However, it is also important that manufacturers have a quality management process to ensure consistent quality. Usually these approvals and manufacturing processes are for the solid plank and therefore full designs of the construction including its external cladding. are required on a site by site basis. CLT as a structural timber product isn’t preservative treated. It is also difficult to ‘post treat’ the panels due to the compact layers of softwood timber making penetration of the preservative across the full cross section difficult to achieve. So, it is important that the design keeps the CLT panel completely dry, particularly at ground level and around critical junctions.

Where structural timber, such as these wall panels are to be used in an external wall construction consideration should be given whether timber treatment is necessary if the species of the timber isn’t sufficiently naturally durable.

The vulnerability of timber in external walls is particularly critical where the timber is positioned in certain areas including at the horizontal damp proof course without the inclusion of a treated sole plate. Whilst the use of CLT panels in external walls is a relatively new occurrence in the UK, wall panels incorporating CLT have been successfully used in Europe.

Premier Guarantee are actively involved with the Structural Timber Association and have recently supported and endorsed technical guidance produced by the STA. The recently reviewed CLT guidance is available via:

STRUCTURAL TIMBER ASSOCIATION: www.structuraltimber.co.uk

BM TRADA: www.bmtrada.co.uk

FOR OUR WARRANTY PURPOSES:

Where projects are proposed that incorporate CLT wall panels; they must not be used with a render or other cladding system that is directly bonded to the wall panel. A drained and vented cavity must be provided.

The CLT panel must be suitably protected as follows:

At DPC level:

The CLT wall panels can be positioned directly onto the horizontal dpc (over the substructure

walls) without a treated timber sole plate providing that:

• The DPC extends at least 50mm past the face of the CLT and in the case of on the cavity wall side- extends down 50mm below the horizontal DPC without bridging the cavity.

• The lowest level of the CLT panel where it sits onto the horizontal dpc must be not less than 150mm above the finished ground level. The residual cavity must extend 225mm below the lowest horizontal DPC level.

• Open brick perpends / Weeps should be sited under the external horizontal DPC in the cladding at 1200mm centres.

• Measures to prevent cold bridging at the substructure wall / ground floor / CLT wall panel junctions must be in place.

• Ground levels immediately in front of the external wall should slope away from the building cladding.

• CLT panels must not be constructed into ‘troughs or pockets’ e.g. for an internal wall panel on a structural slab. The risk of hidden damage from accidental water leaks could lead to moisture collecting around the panel.

Above horizontal DPC level:

• All exposed end grain to the wall panel must be suitably treated (e.g. end grain edges of the panel or where holes are cut through the panel to form openings – windows, doors, flues etc.) The end grain sealant should extend 50mm onto the panel sides.

• There must be a drained and vented cavity with a minimum 50mm residual cavity retained.

• The external wall insulation must be a ‘breathable’ type insulation and directly fixed to the CLT wall panel.

• An approved breathable membrane must be installed to protect the insulation on the cavity side.

• Suitable approved wall ties must be used which are secured to the CLT panel.

• The CLT panels should be protected on the ‘Warm side’ by a suitable vapour control layer

(vcl) unless interstitial condensation risk analysis calculations prove that the risk of interstitial condensation will not occur within the construction.

• The structural engineer must provide details of suitable mechanical fixings to secure the CLT panels to the substructure.

Generally:

• The project using CLT panels must be supported by full structural design specifications.

• General construction should follow the guidance contained within Timber frame section of the Technical Manual.

• Detailing for Gas membranes must be considered on a project by project basis and you should consult with our Warranty Surveyor for further advice.

 

www.premierguarantee.com