Celotex Crown Fix products can be installed in accordance with these instructions
Celotex insulation boards should not be installed when the temperature is at or below 4°C and falling.
- Lay the board on to a deck along with a suitable vapour control layer as specified by the single ply membrane manufacturer. The deck must be structurally sound, dry, clean and if necessary primed.
- The boards should be secured to the deck using a mechanical fixing appropriate for the substrate.
- When fixing the membrane to the insulation, the exact number of fixings used should be determined by the calculation method in BS EN 1991-1-4:2005+A1:2010.
- The membrane is laid over the insulation. To ensure a successful and safe installation the roofing membrane should be installed in line with the guidance given by the manufacturer.
The boards should be laid with all joints tightly butted over the VCL and then mechanically secured through to the deck. When used on metal decks, Celotex Crown-Fix should be laid with the long edges at right angles to the corrugations. When mechanical fasteners are utilised, they should be selected to suit the type of deck used. Fixings should have a minimum 50mm head or plate washer diameter. Fixings should be installed between 50–150mm from the edges and corners of the board.
Celotex recommends the use of thermally broken fixings.
The exact number of fixings required for each zone on a flat roof must be calculated by the use of either BS6399: Part 2: 1997 Code of Practice for Wind Loads, or EN1991-1-4 used with the UK National Annex. A minimum of 6 fixings per board must be used. Where more than 6 fixings per board are required by the wind uplift calculation, the higher figure must be adopted.
Further guidance on fixings and patterns can be sought from fixing manufacturers and in the BRUFMA information document on mechanical fixings for rigid PIR roof boards (see BURFMA ID 1/2009 mechanical fixings guide)
Vapour Control Layer (VCL)
The VCL should be minimum 1000gauge polythene or reinforced aluminium foil. This should be fully sealed at all laps, prior to applying the insulation, using self-adhesive tape appropriate to the type of VCL used.
At perimeters and abutments, the VCL should be turned up around the insulation board edges and a flap of approximately 300mm should be sealed and taped to the top face of the board. The VCL should be loose laid immediately prior to the installation of the roof insulation board.
Where an insulated upstand is needed, Celotex TB4000, Celotex GA4000 and Celotex XR4000 are suitable to meet this requirement.
Different types of weathering systems require different installation instructions and guidelines. Advice on the installation of these weathering systems should be sought from the manufacturer or provider of the weathering system.
It is recommended that Celotex Crown-Fix boards are laid with joints break-bonded. When used on metal decks, the Crown-Fix boards should be laid with the long sides at right angles to the corrugations.
The supporting deck must provide adequate support for the VCL and insulation board with joints being supported by the ridges of the deck. The deck must be structurally sound, dry, clean and where necessary, primed before application of the weathering and insulating system.
Celotex Crown-Fix boards are capable of withstanding the trafficking associated with normal roof laying work. However, flat roofs are generally only designed for occasional lightweight foot track or maintenance access. Where more frequent or heavier access is required, protected walkways should be provided. Under no circumstances should the roof be used as a working platform, either during or after the construction programme.
Celotex insulation boards should be stored dry, flat and clear of the ground. Only as much material as can be installed during a single working period should be removed from storage at any one time. If boards are stored under tarpaulins, care should be taken to prevent rope damage to boards.
When cutting Celotex insulation, dust extraction equipment, eye protection and face masks should be used. Dust or particles in the eyes should be washed out with liberal quantities of water. If skin is sensitive to fibre irritation, apply a barrier cream to exposed areas before handling.