77.5mm Celotex Insulated Plasterboard PL4065 (1200mm x 2400mm)

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£71.69 ex VAT

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Get the best prices on insulated plasterboards here! Celotex 77.5mm is a quality product made up of a polyisocyanurate (PIR) core with a foil lining on one side and a paper lining on the other. The foil lined side of the sheet is bonded to 12.5mm plasterboard. The plasterboard is made up of a Gyproc core with quality paper linings.


  • Celotex as a brand is renowned for its quality products and reliable services
  • Their high-quality products manufactured are virtually impossible to beat in price!
  • Celotex insulation has better thermal efficiency than many other materials
  • The Celotex brand offers materials to suit a wide range of applications including, pitched roofs, flat roofs, walls, floors, and ceilings.
  • Other Celotex product include Thermaclass, cavity wall boards, and insulation boards

77.5mm Insulated Plasterboard

  • 77.5mm – Product code PL4065
  • 77.5mm Insulated Plasterboard is the largest size Celotex manufactures and commonly used in roof applications. This thicker boards are also used in big open areas where size / space is not a factor.
  • The bonded Plasterboard has a tapered edge for an easier and more durable completion.
  • This is a 2-in-1 product means you can improve thermal quality of the building and apply a wall finishing in one application
  • Insulated plasterboards are lightweight making them super easy to handle, cut, and install, this versatile product can be installed within domestic or commercial buildings
  • This product is a 12.5mm plasterboard and 65mm insulation board. This standard board is a safe choice when insulating you home and the thickest made insulated plasterboard products, providing the best thermal performance.
  • The 77.5mm is cost effective and practical
  • This board offers an incredible thermal conductivity of just 0.022W/mK – which for those who don’t know, means this product can generate more heat from the energy in your house, giving more heat your home or office!
  • Whilst staying warm in the winter and cool in the summer, you’re also providing an energy efficient environment that contributes to the reduction of climate change
  • While you think it stops at helping the environment, with less heat escaping, Celotex insulated plasterboards can also save you money on your energy bills. 25% of heat escapes though the roof of your property every year, reducing this will reduce the bills.
  • These boards can be applied to walls and pitched roof applications in either a dot and dab or mechanical fixing application
  • The insulated plasterboards are also available in sizes 37.5mm, 52.5mm, 62.5mm, and 72.5mm to suit every application need
  • All Insulated plasterboards are CFC, HCFC and Formaldehyde Free with zero ozone depletion potential (ODP) and low global warming potential (GWP)
  • Don’t be surprised if you see Insulated Plasterboards referred to as the following, Thermal laminate, Thermaline Boards, Insulation backed plasterboard, Thermal PIR Board.


  • Reaction to Fire: Euroclass B-s1
  • BS EN 13501-1
  • CE Marked (18.DOPPL4000-01) to BS EN 13950
  • BBA Approved (Cert no 16/5357)
  • Achieves a BRE Green Guide A+ rating
  • Quality Management Standard – ISO 9001:2015

More Information:

  • Product code: PL4065
  • Thickness: 12.5mm + 65mm (77.5mm)
  • Size: 2400mm x 1200mm
  • Materials: Gypsum, PIR, Foil, Paper
  • Thermal Conductivity: 0.022W/mK
  • R-Value: 3.00 m2.kW

How are insulation boards installed in roof applications?

When insulating your pitched roof, the insulation applied should have a combined minimum thickness of 180mm. If 120mm insulation board is installed between the rafters, another layer of 65mm insulation should be installed over the top.

Step 1:

Cut and install insulation boards vertically in between the rafters of the pitched roof. Ensure the boards fit snug in between the rafters in the roof and the thickness of the insulation boards matches the depth of the rafters. Ensure any boards joined are tightly butted together. Any boards installed should sit flush with no protrusions.

Step 2:

Cut and installed insulated plasterboard horizontally over the rafters. The boards should meet at the centre of the rafters, lightly butted, and fixed into place with drywall screws or large-headed galvanised clout nails. The screws should penetrate through the board and 25mm into the timber and no less than 10mm from the board’s edges, embedded just below to boards surface.

Step 3:

Seal the perimeter of the Insulated Plasterboards with a flexible sealant.

What type of insulated is used to insulate a pitched roof?

Pitched roofs can be insulated in between the rafters with mineral wool insulation material or rigid PIR insulation. 300mm of insulation is required when using mineral wood. 180mm of insulation is required when using rigid insulation boards. When using rigid insulation, the roof can be complete with a layer of insulation installed horizontally over the insulated rafters followed by plasterboards for a neat finish, particularly if you are creating a room in the roof. Insulated Plasterboard is a quicker alternative although not essential.

What size do I need?

When insulating a pitched roof, a minimum thickness of 180mm should be installed. The size of the Insulated Plasterboard you require depends on the thickness of the insulation board fitted between the rafters. For example, if a 140mm PIR board is installed between the rafters, a 40mm (52.5mm) Insulated Plasterboard should be fitted over the rafter to have an overall 180mm thickness. This decision is also based on the depth of the rafters and if the board meets the building regulations.

Additional information

Dimensions2400 × 1200 mm




Material Type

Polyisocyanurate (PIR)

Pieces Per Pack


Sales Unit


Unit Coverage


Manufacturers Reference


Thermal Conductivity




Fire Rating

Euroclass B

Edge Type



Paper Facing

Weight (kg/m2)


3 reviews for 77.5mm Celotex Insulated Plasterboard PL4065 (1200mm x 2400mm)

  1. Bridget Shepherd

    Good delivery and driver was helpful. I ordered this product for a project in my house and the builder was happy with this product.

  2. Kanan Pate

    I always use Celotex 77.5mm when insulating pitched roofs. Excellent quality product.

  3. Frederick Solomon

    Really pleased with the service! Got a call to confirm my delivery date and a follow up call to make sure it went okay. Superb.

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