Product Installation - Kingspan Thermawall TW55
Insulated Render Systems
Due to insulated render systems being proprietary and utilising different mechanisms for attaching insulation to the wall structure, sitework guidance should be sought from the render system manufacturer. However, in the absence of any other guidance, the instructions laid out below may be followed.
The external masonry wall should be clean, flat, and free from protrusions.
Where an uneven surface remains, it is recommended that a bedding compound can be applied prior to fixing the insulation boards.
External wall insulation should start 150 / 200 / 600* mm below the top surface of the ground floor insulation / perimeter insulation upstand (whichever is higher) for a concrete floor, or 200 mm below the top surface of the ground floor insulation / perimeter insulation upstand (whichever is higher) for a suspended timber floor. (150 mm applies to the UK. 200 mm applies to the Republic of Ireland if a row of insulating blockwork (thermal conductivity < 0.20 W/m.K) is used, otherwise 600 mm applies).
Insulation boards should be installed break–bonded, with joints lightly butted.
Care should be taken to install the specified thickness of insulation around reveal)
Boards of Kingspan Thermawall® TW53 are mechanically fixed to the exterior of masonry external walls, preferably using thermally broken telescopic tube fasteners.
A minimum of 5 fixings are required to secure an insulation board to the masonry wall.
Board edges at openings and external corners should be fixed with fasteners at minimum 300 mm centres.
Fasteners at board edges must be located > 50 mm, and< 150 mm, from edges and corners of the board, and not overlap board joints
The requirement for additional fixings is dependent on the render system being applied and the type of fixing being used.
Wherever possible, care should be taken to avoid cold bridging when attaching services and ancillaries to the exterior of the building.
Depending on the render finish being applied, advice must be sought from the render manufacturer on the EML / glass fibre mesh and bedding mortar to be applied.
In refurbishment projects, sill extenders and flashings should be used around openings, with care taken to avoid cold bridging
Linear Thermal Bridging at Openings
Linear thermal bridging describes the heat loss at junctions between elements, where the geometry of the junction means that a building’s primary insulation layer is not continuous or is reduced. This heat loss is represented by the junction’s psi (ψ)
value. The ψ–values of all the linear thermal bridges in a building are used in whole building carbon dioxide emissions calculation software.
At a window or door openings, in a wall insulated with Kingspan Thermawall® TW53, the linear thermal bridge is the reveal.
This linear thermal bridge can be avoided, by positioning the window frame so that its outer face is flush with the outer surface of the masonry wall, and overlapping the window frame with the external wall insulation.
If this is not possible, this linear thermal bridge can be reduced by insulating the reveal. The key factor is the thermal resistance (R–value) of this insulation layer.
Reveals should be designed to accommodate the 20 mm of Kingspan Thermawall® TW53 required to achieve an R–value of 0.6 m2.K/W, and the depth of the cladding system