Product Installation - Celotex PL4000 - Guides for selected applications
General Installation Advice
Celotex PIR Plasterboard Thermal Laminates are satisfactory for use as an insulating dry lining system for solid or cavity masonry walls of existing dwellings and non-dwellings or buildings of similar occupancy, type and conditions.
They should be installed in accordance with the Certificate holder’s instructions.
The systems are not intended to offer resistance to rain penetration, therefore walls must be already rain resistant and show no signs of water ingress, rain penetration or damp from ground moisture.
It is recommended that services which penetrate the dry lining, such as light switches and power outlets, are kept to a minimum to limit damage to vapour checks.
If present, mould or fungal growth should be treated prior to the application of the systems.
It is essential that proper care and attention is given to maintaining the integrity / continuity of the insulation and facings.
De-rating of any electrical cables in areas where the systems restrict the flow of air should be considered.
PL4000 Installation guidelines for internal lining systems using the plaster dab method
Celotex insulation boards should not be installed when the temperature is at or below 4°C and falling.
Ensure that existing walls are permeable. Strip any gloss paint or vinyl wallpaper.
Cut the 1200mm x 2400mm Celotex PL4000 boards to fit the floor-to-ceiling height of the room.
Ensure a continuous seal at skirting, ceiling level and at openings by applying a continuous band of gypsum adhesive.
Gypsum adhesive at perimeter edges can be replaced with thin timber battens.
Apply further dabs of gypsum adhesive. This should be in accordance with the adhesive manufacturer’s instructions.
Align sheets against the dabs and secure into correct position.
Once the dabs are set, it is recommended that additional secondary fixings be applied to the Celotex PL4000.
Exact fixing details should be in accordance with the recommendations of the fixing manufacturer.
Joints between the boards must be tightly butted, taped and jointed using appropriate tape and jointing material to create the vapour control layer (VCL).
Line window and door reveals with thinner Celotex TB4000 boards to reduce the risk of thermal bridging.
Fix a batten around the edge of the opening and scribe the board to fit the reveal.
Cut the dry lining to suit and mechanically fix into the masonry reveal using proprietary fixings.
Finish using an angle fillet at the frame and an angle bead or scrim tape at external corners.
Please note that to avoid the load being directly applied to the Celotex PL4000, suitable mechanical fixings should be used for other internal fittings.
Advice on suitable fixings should be sought directly from the fixing manufacturer.
Care and preventative measures should be taken when lifting and installing Celotex PL4000 due to the weight of the plasterboard.
Installation guidelines for internal lining systems using mechanical fixings
Ensure that existing walls are permeable. Strip any gloss paint or vinyl wallpaper.
Cut the 1200mm x 2400mm Celotex PL4000 boards to fit the floor-to-ceiling height of the room.
Secure Celotex PL4000 with suitable mechanical fixings. Fixing details should be in accordance with the fixing manufacturer’s instructions.
Joints between the boards must be tightly butted, taped and jointed using appropriate tape and jointing material to create the vapour control layer (VCL).
Line window and door reveals with thinner Celotex TB4000 boards to reduce the risk of thermal bridging.
Fix a batten around the edge of the opening and scribe the board to fit the reveal.
Cut the dry lining to suit and mechanically fix into the masonry reveal using proprietary fixings.
Finish using an angle fillet at the frame and an angle bead or scrim tape at external corners.
Installation guidelines for internal lining systems using mechanical fixings to timber battens
Ensure that existing walls are permeable. Strip any gloss paint or vinyl wallpaper.
Fix treated softwood timber battens to the masonry. They should be set out a maximum of 600mm vertical centres to coincide with the edges of the boards. As a minimum requirement, horizontal battens should be used to support the top and bottom of the board edges.
Galvanised clout nails or timber drywall screws should then be used to fix the boards to the battens. Specific advice on suitable fixings should be sourced directly from the fixings manufacturer.
Joints between the boards should be tightly butted and finished by taping and jointing using appropriate tape and jointing material to create the VCL.
Installation guidelines for internal lining systems using mechanical fixings to metal lining systems
Celotex PL4000 boards can be fixed to a number of proprietary metal frame lining systems. The system should be fixed in accordance with the manufacturer’s instructions.
Masonry Wall Installation
The boards may be installed on masonry construction including clay and calcium silicate bricks, concrete blocks, and natural and reconstituted stone blocks.
With installations that form a void of 20 mm or more (i.e. timber batten or metal furring systems), services can be
incorporated behind the dry lining, making the chasing of the wall unnecessary.
Where the services have a greater
depth than the void, the wall should be chased rather than the insulation.
The installation of the systems require careful detailing around doors and windows to achieve a satisfactory
surface for finishing.
In addition, every attempt should be made to minimise the risk of thermal bridging at reveals
and where heavy separating walls are attached to the external wall.
All work must be designed to accommodate the
thickness of the dry lining, particularly at reveals, heads, sills and in relation to ceiling height.
Where the dimensions of
fixtures are critical (e.g. bathrooms), these should be checked before installation.
Care and preventative measures should be taken when lifting and installing Celotex PL4000 due to the weight of the plasterboard.
Between and Under Rafter Applications
Unventilated
Install the breather membrane over the rafters. Fix battens to the side of the rafters to allow the membrane to sag between the rafters. Alternatively, fix counter battens over the membrane, leaving the entire rafter depth to be filled with insulation. All details are to be in accordance with the membrane manufacturer’s recommendations.
Ventilated
Make sure there is enough rafter depth to accommodate not only the thickness of the Celotex insulation but also a 50mmventilated airspace above the boards.
Fix battens to the inside face of the rafter so that the bottom of the batten is 50mm below the sarking felt.
Ventilated and Unventilated
Measure the space to be filled between the inside face of the rafter prior to cutting the board.
Cut the boards at a slight angle, making the board width slightly oversized on one surface to achieve a ‘friction fit’.
Push the boards into the void between the rafters until they are tight up to the battens or the membrane, ensuring that lateral joints are closely butted. Secure Celotex PL4000 to the underside of the rafters with suitable mechanical fixings. Fixing• details should be in accordance with the fixing manufacturer’s instructions.
Joints between boards must be tightly butted, taped and jointed using appropriate tape and jointing material to create the vapour control layer.
Between and Under Joist Applications
Make sure that there is enough joist depth to accommodate not only the thickness of the Celotex insulation, but also a 50mm ventilated airspace above the boards.
Fix battens to the inside face of the joists so that the bottom of the batten is 50mm below the decking.
Measure the space to be filled between the inside face of the joists prior to cutting the board.
The Celotex Insulation Clip is designed to allow insulation boards to be installed between timber joists quickly and without nails or screws.
Fit the clips at one metre maximum centres along the insulation.
Push the boards into the void between the joists until they are tight up to the underside of stop battens, ensuring that the lateral joints are tightly butted.
Secure Celotex PL4000 to the underside of the joists.
Joints between the boards must be tightly butted, taped and jointed using appropriate tape and jointing material to create the vapour control layer
Composite systems can be used to combine Celotex insulation under joist lining with quilt type insulant between the joists which will provide acoustic, as well as thermal insulation.
This option is particularly useful when upgrading to modern acoustic insulation standards. When updating an existing ceiling,
Celotex PL4000, GD5000 or GS5000 can be fitted directly underneath the ceiling, providing there is no vapour check layer such as gloss paint or foil backed plasterboard.
Always ensure that there is a 50mm minimum ventilation gap above any original insulation.
Ventilation must be provided above an insulated ceiling directly through the cold void. Failure to do so could result in serious condensation problems that may lead to decay and possible failure.
Health & Safety
Advice or information regarding storage and handling of Celotex products, please refer to to the 'literature' pages of the website at www.celotex.co.uk