New Build Secondary School & Sixth Form, Kenilworth

Brief:

Although the largest buildings would not exceed 3 storeys in height, the specification still called for a non-combustible external wall insulation system. The structure would comprise a lightweight steel frame with cementitious sheathing boards overlying them, so the chosen EWI system would need to be capable of being securely affixed, and able to protect the underlying structure against water ingress and subsequent corrosion.

As part of the planning process, Permarock technical staff provided the client’s team with visualisations and coloured material samples. They also made multiple site visits in order to develop suitable designs and to ensure that the system could be securely and safely affixed. Other assistance was provided as required: telephone and email support, and project-specific training for installers.

Design and Specification:

The chosen EWI system comprised:

• Permarock Mineral Fibre External Wall Insulation System with insulation boards adhesively bonded and mechanically fixed to the substrate;
• Permarock Silicone^Ultra K Finish (textured render).

When combined with Permarock Silicone^Ultra K finish, Permarock Mineral Fibre EWI systems achieve an A2-s1,d0 reaction to fire classification (EN 13501-1:2007 + A1:2009) and can be used on buildings of any height.

The Permarock Mineral Fibre Dual Density Insulation was supplied in boards measuring 1200 mm x 600 mm. They were generally installed in thicknesses of 170 mm, although board thicknesses of 130 mm were used in certain areas in order to preserve the design and appearance of recessed wall panels. In all cases, the boards were securely affixed using both a cement-based adhesive and galvanised steel screws.

The chosen finish was Permarock Silicone^Ultra K, a textured render with a nominal 15 mm grain size. This met all the demands of the specification: it would protect the substrate against exposure to the worst of British weather conditions, and when applied over the mineral fibre boards, it should offer a working life of well over 30 years. What’s more, its combination of antimicrobial inhibitors and nano-quartz technology would help to maintain a bright clean finish by shedding dirt and resisting the growth of mould, algae and other unsightly growths.