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Kingspan Kooltherm K5 Phenolic External Wall Board

High performance Kingspan product, available in most popular thickness’s from the manufacturers, therefore short lead-times apply. This Kooltherm Range includes the following readily available product thickness's 20mm, 50mm, 60mm and 70mm. Manufactured to order are the following thickness's 30mm, 40mm, 55mm, 80mm, 90mm and 100mm.

Product Functions Kingspan Kooltherm K5 EWBperformance thermal insulation board faced on both sides with a plain (coated) glass tissue autohesively bonded to the insulation core

Kingspan K5 is purpose designed premium performance rigid phenolic insulation for fixing to masonry or timber frame walls behind either traditional or lightweight polymer modified render systems.


Product Description

Faced on both sides with tissue based facing, bonded to the insulation core, which is a CFC/HCFC free rigid board of a typical density of 40 kg/m3 with a compressive strength that typically exceeds 120 kPa.

The Board Facings

K5 EWB is faced on both sides with a tissue based facing autohesively bonded to the insulation core during manufacture

The Core

The core of Kingspan Kooltherm® K5 Floorboard is a premium performance rigid thermoset modified resin insulant manufactured with a blowing agent that has zero Ozone Depletion Potential (ODP) and low Global Warming Potential (GWP).

Compressive Strength

The compressive strength of Kingspan Kooltherm® K5 Floorboard typically exceeds 120 kPa at 10% compression, when tested to BS / I.S. EN 826: 1996 (Thermal insulating products for building applications. Determination of compression behaviour).

Water Vapour Resistivity

Kingspan Kooltherm® K5 Floorboard produced at Kingspan Insulation’s Pembridge manufacturing facility typically achieves a resistivity greater than 300 MN.s/g.m when tested in accordance with BS EN 12086: 1997 / I.S. EN 12086: 1998 (Thermal insulating products for building applications Determination of water vapour transmission properties).


If correctly installed, K5 Floorboard can have 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 adhesive 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.
The insulation core and facings used in the manufacture of K5 Floor boards resist attack by mould and microbial growth, and do not provide any food value to vermin.

Product Benefits

Developed specifically for use in external walls, Kingspan K5 is the highest performance insulation board that offers:
Premium performance rigid phenolic insulation – thermal conductivity as low as 0.021 W/m.K
Suitable for use behind traditional and lightweight polymer modified renders
Transforms and upgrades the appearance of existing buildings
Resistant to the passage of water vapour
Easy to handle and install
Ideal for new build and refurbishment
Non–deleterious material
CFC/HCFC–free with zero Ozone Depletion Potential (ODP)

Product availability indicators

K5 - Price and Availability Advisory:

Presently there are no availability restrictions, apart from manufacturing lead-times and minimum quantity order levels on the 80mm, 120mm, 130mm and 140mm boards

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 K5 Phenolic Insulation Boards for external wall applications

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 K5 25 x 0.6x1.2 = 18.00m² 20 0.023 0.85 1.18 0.94 16.92
Kingspan K5 16 x 0.6x1.2 = 11.52m² 30 0.021 1.40 0.71 1.34 15.44
Kingspan K5 12 x 0.6x1.2 = 8.64m² 40 0.021 1.90 0.53 1.74 15.03
Kingspan K5 10 x 0.6x1.2 = 7.20m² 50 0.020 2.50 0.40 2.14 15.41
Kingspan K5 9 x 0.6x1.2 = 6.48m² 55 0.020 2.75 0.37 2.34 15.16
Kingspan K5 8 x 0.6x1.2 = 5.76m² 60 0.020 3.00 0.33 2.54 14.63
Kingspan K5 6 x 0.6x1.2 = 4.32m² 70 0.020 3.50 0.29 2.94 12.70
Kingspan K5 6 x 0.6x1.2 = 4.32m² 80 0.020 4.00 0.25 3.34 14.43
Kingspan K5 4 x 0.6x1.2 = 2.88m² 90 0.020 4.50 0.22 3.74 10.77
Kingspan K5 5 x 0.6x1.2 = 3.60m² 100 0.020 5.00 0.20 4.14 14.90

Thermal conductivity / Lambda value (W/mK) = 0.023 - 0.020 | Compressive strength (kPa) = ≥ 120 | Water vapour resistance (MNs/g) = > 15 | Please Note: R-Value = Thermal Resistance; U Value = Thermal Transmittance Co-efficient; Compressive strength = kiloPascals; Vapour resistance = MegaNewton seconds per gram.

Product Information and Certification

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

Product Installation - Kingspan K5

Kooltherm K5 - Installing insulated render systems

As insulated render systems are proprietary and utilise different mechanisms for attaching insulation to the wall structure, site work guidance should be sought from the system manufacturer.

However, in the absence of any other guidance K5 insulation boards are mechanically fixed to the exterior of masonry external walls using anchor bolts, expansion fixings, proprietary fixings or bedded in render.

Kooltherm K5 Structural concrete wall build-up diagramIn the case of timber frame walls the K5 insulation boards are temporarily pinned in place with all joints lightly butted.

A breathable membrane (such as Dupont Tyvek Supro) is applied over the insulation boards and temporarily stapled or pinned in place.

Preservative treated softwood battens are fixed vertically at centres to coincide with the timber frame wall studs. The expanded metal / cementitious board to carry the render is then fixed to the vertical battens.

Sill extenders and flashings are used around openings, although the use of rigid phenolic insulation minimises the overall thickness of the external render system.


Cutting should be carried out either by using a fine toothed saw, or by scoring with a sharp knife, snapping the board over a straight edge and then cutting the facing on the other side. Ensure accurate trimming to achieve close-butting joints and continuity of insulation.

Fixings for Attachment of Vertical Counter Battens

Approved fixings should be applied at centres appropriate to the design of the wall and location of the building, in order to fix vertical battens through to the wall studs of a timber frame or masonry wall.

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


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