Thermazone Roofboard - Roof Insulation Boards

Thermazone Roofboard is a high performance Polyisocyanurate insulation board with mineral coated glass facers suitable for use below single ply , partially bonded pour and roll and heat activated fully adhered roof membranes, single ply waterproofing systems and partially bonded built-up felt. It is suitable for use over all types of structural deck and must always be laid over a vapour control layer.

Thermazone Roofboard is available in flat or in XtraFall tapered variants.


Features & Benefits

  • Highly efficient PIR rigid insulation
  • Thermal conductivity as low as 0.024W/mK
  • Excellent adhesion for Thermically Activated Bitumen membranes
  • LPCB/FM approved
  • Non-deleterious material
  • Manufactured without the use of CFC’s/HCFC’s Zero ODP and Low GWP
  • Suitable for new build and refurbishment projects

Insulation Board Core & Facings

The Core: Thermazone Roofboard insulation is manufactured from a high performance CFC/HCFC– free polyisocyanurate (PIR) based formulation with a typical density of 32 kg/m3.

Thermazone Roofboard insulation is manufactured without the use of CFCs/HCFCs and has zero Ozone Depletion Potential (ODP).

Insulation Board Facings: Thermazone Roofboard insulation is faced on the both sides with a mineralised glass tissue autohesively bonded to the insulation core during manufacture.

Technical Details

Performance Data:

Board Size (Flat Boards) 1200 x 600mm, 2400mm x 1200mm
Thicknesses (Flat Boards) 25, 30, 40, 50, 60, 80, 90, 100, 110, 120, 130, 140, 150 & 160mm

Tapered Boards

Thermazone® Torch-On insulation is available in a tapered version, tapering at 1:60 fall across a 1200 mm length.
Board Size (Tapered Boards) 1200mm x 1200mm
Thicknesses (Tapered Boards) 30-50, 50-70, 70-90, 90-110mm

Board Size (Jumper/Packer Boards)

1200 x 1200mm
Thickness (Jumper/Packer Boards) 80mm

Typical Physical Characteristics
Density (Foam Core) 32kg/m3
Compressive Strength >150kPa @ 10% Compression
Water Vapour Resistivity >15 MN-s/g
Thermal Conductivity 0.026 W/m.K (insulant thickness < 80 mm);
0.025 W/m.K (insulant thickness 80 - 119 mm); and
0.024 W/m.K (insulant thickness > 120mm).
Thermal Resistance Thermal resistance (R - value) varies with thickness and is calculated by dividing the thickness of the board (expressed in metres) by its thermal conductivity value


Insulation Board Attachment

Thermazone Roofboard must be bonded to VCL or mechanically fixed in accordance with the Icopal project fixing calculation.

Where tapered insulation installations are specified all boards must be laid in accordance with the XtraFall Insulation layout drawing..

During laying, water must not ingress under the insulation layer.

Day/night seals must be used during all interruptions to works.
Careful attention to roof details and setting out of laying pattern of XtraFall is required.

XtraFall tapered systems are designed to be installed by a competent contractor, who is experienced with this type of product.

Boards that have been damaged or allowed to get wet should never be used.

When Thermazone Roof Board is used over metal decks attention must be paid to the requirement of the insulation board to comply with the minimum thicknesses shown in the table below.

Trough Width (mm)  Minimum Board Thickness (mm)
< 75 25
76 - 100 30
101 - 125 35
126 - 150 40
151 - 175 45
176 - 200 50



Insulation can be bonded/adhered or mechanically fixed to the substrate. The location/quantity of fixings to be in accordance with the Icopal fixing calculation.

Thermazone® XtraFall Taper System

A Thermazone® XtraFall Torch-On System provides the designer and contractor with a precise, technically excellent solution to providing thermal insulation and bespoke drainage on a flat roof. A Thermazone XtraFall Taper System comprises factory laminated boards and factory cut hip and valley pieces which allow for the creation of mitres without on-site cutting thereby reducing installation times, cutting errors and the associated labour and waste costs. Each component is clearly identified by board type and the direction of fall. 

Survey and Design Service

Icopal offer a free no obligation in-house design service for clients looking to specify an Icopal flat roof system incorporating XtraFall insulation.

Our area technical managers are trained to survey roof areas using the latest and most accurate equipment available, including digital inclinometers and laser levels.

Cut to falls designs are produced by our tapered insulation design team and can be tailored to the requirements of any project. U-Value calculations and condensation risk analysis calculations are available on request.

Insured guarantees are available for Icopal flat roof systems incorporating XtraFall tapered insulation. For further details on this please contact Icopal Technical Services.

Tel: 0330 123 4585



download pdf Thermazone XtraFall - Tapered Insulation Systems (ICO3218)


Contact Icopal 0161 8654444

Find Local Support

To discuss your project in more detail please contact
Your Local Area Manager


Technical Support


0330 123 4585



Sales Enquiries & Orders


0843 224 7400


0843 224 7401


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