The Hereford Academy, a learning community for 11 - 19 year olds in the south of the city of Hereford, required a fast and effective external sheathing solution as part of a £22 million pound new build project.
Lafarge Plasterboard, working with contractors Willmott Dixon Construction and subcontractors Manorcraft Interior Systems, supplied GTEC Aqua Board, the UK’s first gypsum based board for wet and high humidity applications, to be installed as part of an external sheathing system to the steel frame behind the brickwork of the development.
Michael Chaney, Project Surveyor for Willmott Dixon Construction, said: “The Academy is being built on playing fields of the existing site. When it is completed the children will be moved to the new building whereupon the second phase will commence - demolishing the existing building to build new sports pitches.”
Aqua Board is the latest innovation in high performance gypsum boards and goes against all the conventions of the traditional use of plasterboard. Its mould and water resistance means it can be installed internally as well as externally, where it is subject to all weather conditions. It can be recycled and has BBA certification for single layer application as part of an External Insulation and Finishing System. Lafarge has ISO140001 environmental accreditation and offers a waste plasterboard management service.
Simon Scrase, Technical Specification Manager for Lafarge Plasterboard, said: “To comply with Approved Document Part L (Conservation of Fuel and Power) of the Building Regulations, uncontrolled air leakage from a building envelope must be minimised, subject to an air leakage test. This is one of the major challenges for a contractor in maintaining the air tightness of any external construction. Usually, internal drylining is relied on to carry out this function by sealing the perimeter with an intumescent and acoustic sealant. However, if at a latter stage any penetration is made in the internal drylining, for example inserting an electrical socket, the air tightness is breached.”
“Installing Aqua Board on the exterior of the steel frame provides an airtight and weather tight seal. Also, by providing the seal early in the construction, the internal drylining can commence ahead of programme, thus increasing the speed of the construction.”
Michael Chaney, Project Surveyor for Willmott Dixon Construction, said: “Lafarge put forward GTEC Aqua Board as an alternative to cement particle board and we could see the benefits with regards to manual handling and speed of installation on site as there is no need for mechanical cutting.”
Chris Moreton, Managing Director of Manorcraft Interior Systems Ltd, said: “It is difficult if not impossible to provide the same type of ‘seal’ with a more traditional board like cement particle board. Because it is gypsum based, Aqua Board is lighter and therefore easier to handle, plus it is much easier to cut than other sheathing boards, using the ‘score and snap technique’. We estimated that using Aqua Board saved at least 50% installation time in comparison to cement particle board.”
Chris added: “This is actually the second project where we have used Aqua Board externally. We have just completed a project at the University of Wales, Cardiff where we utilised Aqua Board as an insulated render substrate. The weather resisting qualities along with ‘ease of use’ make Aqua Board a viable alternative to more traditional cement particle boards.”
Aqua Board has many advantages over cement particle boards – safer, lighter and quicker . Cement particle boards pose a much higher health and safety risk as they must be cut using power saws and require a segregated area with dust extraction and fire extinguishers. Aqua Board is also much lighter, at 10.8kg/m2 versus 15kg/m2 for cement particle board. As a result of these factors, the sheathing at the Hereford Academy was installed well ahead of schedule. Aqua Board is available in 12.5mm and 15mm thicknesses and various lengths.
