Minimum order £500.00 Ex-VAT - Delivery Vehicle Access: 28 ton curtain-sided lorry off-load requirement.

    Shopping Basket


Celotex Crown-Fix Mechanically Fixed Single Ply Flat Roof Board - NEW!


Specialist Celotex Product, Crown-Fix is available in thickness’s between 50mm – 140mm from the manufacturer; lead-times apply to the following products: FX0050, FX0100, FX0110, FX0120 and FX0140

Due to Celotex ordering constraints, we may only be able to source these items in multiples of two packs.

Celotex's new Crown Fix range of higher specification boards replaces TD4000 Range.

Product Description

Celotex Crown-Fix is a purpose designed rigid polyisocyanurate (PIR) flat roofing insulation board use in single-ply membrane applications where the single-ply membrane is to be mechanically fixed.

This is a high performance flat roofing insulation board featuring low emissivity aluminium facers on both sides, a low lambda value of 0.022 W/mK and a compressive strength of up to 150 kPa, providing increased dimensional stability and added robustness.

Used in mechanically fixed single-ply applications and is suitable for fully sealed metal, timber and concrete decks. 

Crown-Fix provides a quick and easy way to provide high thermal performance in flat roofing structures. Crown-Fix is CFC/HCFC free with zero ODP and low GWP and CE marking compliance to BS EN 13165.

Crown-Fix is manufactured in accordance with quality management system ISO 9001 and environmental management system ISO 14001.

Board size: 1200 x 2400mm.

Product Benefits

  • Specialist Celotex Product, Crown-Fix is available in thickness’s of 50mm, 100mm, 110mm, 120mm & 140mm
  • Crown-Fix is CFC/HCFC free with zero ODP and low GWP and CE marking compliance to BS EN 13165.
  • Crown-Fix is manufactured in accordance with quality management system ISO 9001 and environmental management system ISO 14001.
  • Innovative composite facers on both sides
  • Low lambda 0.022W/mK offering high thermal performance
  • Compatible with bonded single ply membranes
  • Suitable to be used on fully sealed metal, timber and concrete decks
  • Excellent compressive strength (≥ 150 kPa), giving it increased dimensional stability and added robustness Ideal for new build or refurbishment projects
  • Secured to the deck with fully bonded systems or thermally broken or mechanical fasteners

Product availability indicators

Excellent = Product Availability Excellent  Good = Product Availability Good  Fair = Product Availability Fair  Poor =  Product Availability Poor  Undetermined = Product Availability Undetermined
Availability relies on stock levels at closest depots and upon transport logistics to effect deliveries

Technical Data

Celotex Crown-Fix Mechanically Fixed Single Ply Flat Roofing PIR Boards

Product Code

Board dimensions

Thickness (mm)

λ Value (w/mK)

R-value (m²K/W)

U Value (W/m²K)

Weight (kg/m²)

Unit weight (kg)

Crown-Fix (FX0050) 24 x 1.2 x 2.4m = 69.12m² 50 0.022 2.25 0.44 2.16 149.30
Crown-Fix (FX0100) 12 x 1.2 x 2.4m = 34.56m² 100 0.022 4.50 0.22 4.08 141.00
Crown-Fix (FX0110) 11 x 1.2 x 2.4m = 31.68m² 110 0.022 5.00 0.20 4.47 141.61
Crown-Fix (FX0120) 10 x 1.2 x 2.4m = 28.80m² 120 0.022 5.45 0.18 4.85 139.68
Crown-Fix (FX0140) 8 x 1.2 x 2.4m = 23.04m² 140 0.022 6.35 0.16 5.62 129.48
Thermal conductivity / Lambda value (W/mK) = 0.022 | Compressive strength (kPa) = ≥ 150 | Dimensional stability DS(70,90)3 – DS(-20-)1.
Please Note: R-Value = Thermal Resistance; U Value = Thermal Transmittance Co-efficient; Compressive strength = kiloPascals; Vapour resistance = MegaNewton seconds per gram.

Construction Build Up

Construction Concrete Deck Metal Deck Timber Deck

Metal fixing

Thermally broken fixing

Metal fixing

Thermally broken fixing

Metal fixing

Thermally broken fixing

Outside surface resistance - - -
Single ply membrane 1.5 1.5 1.5 1.5 1.5 1.5
Variable layer See Below See Below See Below See Below See Below See Below
Polythene 1000 gauge, VCL - - - - - -
Concrete deck 250 250 n/a n/a n/a n/a
Metal deck n/a n/a 1.5 1.5 n/a n/a
Timber deck plywood n/a n/a n/a n/a 19 19
Cavity between joist @ 11.7% bridging n/a n/a n/a n/a 150 150
Plasterboard n/a n/a 12.5 12.5 12.5 12.5
Inside surface resistance - - - - - -
Variable layer product Thickness (mm) U-value (W/m2K) U-value (W/m2K) U-value (W/m2K)
Celotex Crown-Fix 100 0.22 0.21 0.22 0.20 0.21 0.20
Celotex Crown-Fix 110 0.20 0.19 0.20 0.19 0.19 0.18
Celotex Crown-Fix 120 0.19 0.17 0.18 0.17 0.18 0.17
Celotex Crown-Fix 140 0.16 0.15 0.16 0.15 0.15 0.14

Product Information and Certification

Links to manufacturer's information. Click to download in a separate browser window.
Celotex Crown-Fix Datasheet | Celotex Mechanically Fixed Flat Roof applications guide | Celotex Crown-Fix CE Marking | Celotex Handy Guide | Celotex Flat Roof Specification Guide

Product Installation

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.

Mechanical fastening

Celotex Crown-Fix high performanceinsulationin mechanically fixed, single ply flat roofing systems where the higher compressive strength of the board gives improved resistance to site traffic during installation

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.

Weathering system

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.

Laying Pattern

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.

Supporting Deck

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.

Contact Manufacturer

Celotex Limited

Lady Lane Industrial Estate, Hadleigh, Ipswich, Suffolk, IP7 6BA

Celotex Technical Advisory Service.

Telephone: 0901 996 0100 (30p per minute) - Fax: 01473 820 889
Web sites: Celotex Home Page / Celotex U-Value Calculator.

Contact us

Insulation Online Limited

Sales Office only:

39 Normandy Road, Worthing, West Sussex, BN14 7DX, UK

Telephone: 0333 8000 828