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Kingspan TW55 Thermawall Rigid PIR Insulation Boards

Kingspan's popular polyisocyanurate products are available in most popular thickness’s from the manufacturer, in which case short lead-times apply. The most popular board sizes may be available from stock.

Kingspan TW55, TF70 and TP10 are readily available in the following product thickness's 20mm, 25mm, 30mm, 40mm, 50mm, 60mm, 70mm, 75mm, 80mm, 90mm, 100mm, 105mm, 120mm and 150mm.
Manufactured to order are the following thickness's 45mm, 55mm, 65mm, 85mm, 110mm, 115mm, 130mm, 135mm and 140mm

Product Functions

Thermawall TW55 rigid PIR boards used for Insulation for timber and steel framing systems

The Thermawall TW55 Range comprises performance rigid PIR boards used for Insulation for timber and steel framing systems.

Please note:
To emphasise the application specific suitability of ThermaWall TW55, Thermapitch TP10, and ThermaFloor TF70, Kingspan have branded the same product with these three different names.

Common applications for this product include ...
Single Timber Frame Wall Lining, Steel Stud Frame Walls, Timber Frame Wall Lining, and Timber Frame Walls Sheathing


Product Description

The Front Facings

TW55 is faced on both sides with a low emissivity composite foil facing which is highly resistant to the transmission of water vapour. This reflective, low emissivity surface can effectively double the thermal resistance of the cavity in which the board is placed.

The Core

The core of TW55 is manufactured from trademarked Nilflam technology (a high performance CFC/HCFC free polyisocyanurate (PIR) based formulation). TW55 has a typical density of 32 kg/m3.

TW55 is manufactured without the use of CFCs/HCFCs and has zero Ozone Depletion Potential (ODP).

Compressive Strength

Typically exceeds 140 kPa at 10% compression when tested to BS EN 826: 1996 (Thermal insulating products for building applications. Determination of compression behaviour).

Water Vapour Resistance

Modified to include board facings, the boards achieve a resistance far greater than 100 MN.s/g, when tested in accordance with BS 4370–2: 1993 (Methods of test for rigid cellular materials. Methods 7 to 9)
Where additional vapour control is required an appropriate surface treatment should be applied over the completed insulated wall area (see ‘Water Vapour Control’)


If correctly applied, the TW55 Board has an indefinite life. Its durability depends on the supporting structure and the conditions of its use.

Resistance to Solvents, Fungi & Rodents

The insulation core is resistant to short–term contact with petrol and with most dilute acids, alkalis and mineral oils.
However, it is recommended that any spills be cleaned off fully before the boards are installed. Ensure that safe methods of cleaning are used, as recommended by the suppliers of the spilt liquid. The insulation core is not resistant to some solvent–based adhesives systems, particularly those containing methyl ethyl ketone. Adhesives containing such solvents should not be used in association with this product.

Damaged boards or boards that have been in contact with harsh solvents or acids should not be used.

Fire Performance

TW55, when subjected to British Standard fire tests, achieves the results given below.
Test - BS 476–3: 1958 (External fire membrane adopted exposure roof test)
Result - SAA rating
Test - BS 476–7: 1997 (Fire tests on building materials and structures. Method of test to determine the classification of the surface spread of flame of products
Result - Class 1 rating

Product Benefits

    High performance rigid PIR thermoset insulation – thermal conductivity 0.022 W/m.K
    High performance rigid thermoset insulation – thermal conductivity 0.022 W/m.K
    Can be used between studs or as an insulating sheathing
    Suitable for use with timber
    frame and steel frame wall constructions
    Unaffected by air infiltration
    Resistant to the passage of water vapour
    Easy to handle and install
    Ideal for new build or refurbishment
    Non–deleterious material
    Manufactured with a blowing agent that has zero ODP and low GWP

Product availability indicators

TW55 - Price and Availability Advisory:

Presently there are no availability restrictions, apart from manufacturing lead-times and minimum quantity order levels on the 45mm, 55mm, 65mm, 85mm, 110mm, 115mm, 130mm, 135mm and 140mm

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

Kingspan TW55 PIR Wall Framing System Insulation 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)

Kingspan TW55 20mm 15 x 1.2m x 2.4m = 43.2m² 20 0.022 0.90 1.12 0.98 42.45
Kingspan TW55 25mm 12 x 1.2m x 2.4m = 34.56m² 25 0.022 1.10 0.91 1.14 39.48
Kingspan TW55 30mm 10 x 1.2m x 2.4m = 28.8m² 30 0.022 1.35 0.75 1.30 37.50
Kingspan TW55 40mm 8 x 1.2m x 2.4m = 23.04m² 40 0.022 1.80 0.56 1.62 37.36
Kingspan TW55 45mm 7 x 1.2m x 2.4m = 20.16m² 45 0.022 2.00 0.50 1.78 35.91
Kingspan TW55 50mm 6 x 1.2m x 2.4m = 17.28m² 50 0.022 2.25 0.45 1.91 33.06
Kingspan TW55 55mm 5 x 1.2m x 2.4m = 14.4m² 55 0.022 2.50 0.40 2.10 30.25
Kingspan TW55 60mm 5 x 1.2m x 2.4m = 14.4m² 60 0.022 2.70 0.38 2.26 32.55
Kingspan TW55 65mm 4 x 1.2m x 2.4m = 11.52m² 65 0.022 2.95 0.34 2.42 27.88
Kingspan TW55 70mm 4 x 1.2m x 2.4m = 11.52m² 70 0.022 3.15 0.32 2.58 29.76
Kingspan TW55 75mm 4 x 1.2m x 2.4m = 11.52m² 75 0.022 3.40 0.30 2.74 31.60
Kingspan TW55 80mm 4 x 1.2m x 2.4m = 11.52m² 80 0.022 3.60 0.28 2.90 33.44
Kingspan TW55 85mm 3 x 1.2m x 2.4m = 8.64m² 85 0.022 3.85 0.26 3.06 26.46
Kingspan TW55 90mm 3 x 1.2m x 2.4m = 8.64m² 90 0.022 4.05 0.25 3.22 27.84
Kingspan TW55 100mm 3 x 1.2m x 2.4m = 8.64m² 100 0.022 4.50 0.23 3.54 30.60
Kingspan TW55 110mm 3 x 1.2m x 2.4m = 8.64m² 110 0.022 5.00 0.20 3.86 33.36
Kingspan TW55 120mm 2 x 1.2m x 2.4m = 5.76m² 120 0.022 5.45 0.19 4.18 24.08
Kingspan TW55 125mm 2 x 1.2m x 2.4m = 5.76m² 125 0.022 5.65 0.18 4.34 25.00
Kingspan TW55 130mm 2 x 1.2m x 2.4m = 5.76m² 130 0.022 5.90 0.17 4.40 25.36
Kingspan TW55 140mm 2 x 1.2m x 2.4m = 5.76m² 140 0.022 6.35 0.16 4.82 27.78
Kingspan TW55 150mm 2 x 1.2m x 2.4m = 5.76m² 150 0.022 6.80 0.15 5.14 29.62
Thermal conductivity / Lambda value (W/mK) = 0.022 to 0.022 | Compressive Strength (kPa) = > 140 | Water vapour resistance (MNs/g) = > 100 | Fire Performance = Class 1 | Please Note: R-Value = Thermal Resistance; U-Value = Thermal Transmittance Co-efficient; Compressive Strength = kiloPascals; Vapour resistance = MegaNewton second gram

Product Information and Certification

Links to manufacturer's information. Click to download in a separate browser window.

Kingspan TW55 Datasheet | Kingspan Product Selector | Kingspan Design Manual | Kingspan BBA U-Value Compliancy Cert. | TW55 CE Performance Declaration

Kingspan Kooltherm® TW55 Range - Certification

Kingspan Thermawall® TW55 is manufactured to the highest standards in accordance with BS 4841–1 Rigid polyisocyanurate (PIR) and polyurethane (PUR) products for building end–use applications. Specification for laminated insulation boards with auto–adhesively or separately bonded facings).
Kingspan Thermawall® TW55 is also manufactured to the highest standards under a management system certified to BS / I.S. EN ISO 9001: 2008 (Quality management systems requirements), BS / I.S. EN ISO 14001: 2004 (Environmental Management Systems requirements) and BS /I.S OHSAS 18001: 2007 (Health and Safety Management Systems Requirements).

CE Marking - Kingspan has provided Decelerations of Performance for its products. CE marking is the visible sign, that the product has met the requirements of the European Norms (ENs) and is therefore compliant with the Construction Products Regulation (CPR).

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Product Installation - Kingspan Thermawall TW55

Internal Dry Lining with Insulation Between Timber Framework

The timber framework, backed with strips of damp proof course (DPC), should be mechanically fixed to the masonry wall.

The timbers should be deep enough to accommodate the required thickness of insulation and a 25 mm (min.) air space between the insulation and the masonry.

To avoid insulation boards moving within the timber framework cavity, nail treated softwood battens to the side of the timber members to provide a ‘stop’.

This ‘stop’ should be positioned to allow the insulation boards to finish flush with the inner surface of the timbers.

Measure the distance between timber members before cutting Kingspan Thermawall TW55 as spacings can vary.

Insulation boards may be temporarily held to the ‘stop’ battens with large headed clout nails.

Ensure there is a tight fit between the boards and the adjoining timbers, and fill all gaps with expanding urethane sealant.

The boards will be further restrained by the plasterboard / insulated plasterboard lining, fixed to the inside face of the timbers.

When utilising Kingspan Thermawall TW55 between timbers, a vapour control layer should be installed. This can be provided by vapour check plasterboard, such as Kingspan K18 Insulated Plasterboard, the use of a layer of polythene sheeting (with appropriate detailing at joints, penetrations and wall perimeters) or by the application of two coats of Gyproc Drywall Sealer.

Inside Studs / Timbers Layer of Insulation

 Please refer to Kingspan Kooltherm K8 Insulated Plasterboard for fixing instructions.

Contact Manufacturer

Kingspan Limited

Kingspan Kooltherm Phenolic Foam, Therma PIR, and Styrozone Polystyrene range of rigid insulation boards

Pembridge, Leominster, Herefordshire, HR6 9LA

Kingspan Technical Advisory Service.

Telephone: 01544 388 601 - Fax: 01544 388 888
Email:  /
Web sites: Kingspan Home Page / Kingspan U-Value Calculator.

Contact us

Insulation Online Limited

Sales Office only:

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

Telephone: 0333 8000 828