Eurothane Silver for thin roof insulation: what does a thermal conductivity of 0.022 offer?

Changing the lambda alone is not enough, because the board’s broad range of applications does not mean that components from different systems can be combined at will. The solution should allow one agreed system to be selected before the insulation and waterproof covering are ordered. As a starting point for comparing variants, record the substrate, the waterproofing variant and the documentation of how the roof layers are connected.

Eurothane Silver is declared with a lambda of 0.022 W/(m·K) for the 20–200 mm range. The choice of thickness should nevertheless follow from calculations for the building component.

When comparing polyurethane boards, include the Eurothane Silver layer selected according to a lambda of 0.022 W/(m·K) and the required roof height. The influence of fixings and terminations must be checked in a calculation of the whole roof with Eurothane Silver, so that the comparison relates to the same thermal effect. The result must be read cautiously, since the R of an equal section of board does not include a correction for each fixing passing through the insulation. The calculation is intended to help set the material parameter against the geometry and fixing method of the actual roof. In the energy summary, show the thickness of the main field, the number and type of fixings and the thermal insulation perimeter detail, so that it is clear what exactly has changed between the solutions.

A large Eurothane Silver field may have a good thermal result while the roof perimeter still needs improvement. It is worth analysing the junction with the parapet and the points penetrated by fixings separately. Increasing the thickness over the entire area does not always solve a local problem. First the route of the continuous insulation and the actual fixing method must be established. Only such a picture allows variants that reduce heat losses of the whole system to be compared.

Eurothane Silver boards come in two formats: 600 × 1200 mm and 2400 × 1200 mm. The 20 mm variant is intended only for the smaller of these formats.

Check the choice of the 600 × 1200 or 2400 × 1200 mm format and the order for a specific edge, because continuous polyurethane insulation also requires correct terminations. The Silver format and edge must be matched to the delivery thickness and the number of obstacles on the roof slope, because losses at joints must be assessed together with the main insulation field. A good joint does not arise automatically, since the 20 mm variant appears in the datasheet only in the smaller format. The layout of elements should allow the insulation to be set out according to the variant actually available for the adopted thickness. On the detail drawing, show the dimension of the supplied board, the straight edge or ordered rebate and the coverage area; this record will make it easier to check the work later.

In a system with Eurothane Silver, the vapour barrier and waterproofing must be selected to suit the conditions in the building. The gas-tight surface of the board itself does not close the gaps present across the whole roof.

When assessing the durability of the thermal effect, include the junction of the roof field with the parapet wall and the services routed through the roof. The waterproof covering and the vapour control layer must be connected at the parapet and at service penetrations if the insulation is to perform under the conditions assumed in the design. Polyurethane foam does not replace the protective layers: the gas-tight foil on Eurothane Silver leaves all gaps between elements to be resolved. The intended protections should allow the sealing layers to be connected where different materials meet, without reducing the task to taping over the boards. Before covering up, assess the arrangement of the vapour control layer, the upstand of the covering and the sealing method for the specific penetration, because later repair may require opening the finished building element.

According to the September 2026 Eurothane Silver datasheet, the 20 mm board achieves CS120, while from 30 mm it achieves CS150. The reaction to fire of the board itself from 30 mm falls within class F, whereas for 20 mm it remains undetermined.

The thickness limitation does not exempt from checking other requirements, so analyse the difference between CS120 for 20 mm and CS150 from 30 mm given in the current datasheet. After changing the Silver thickness, the mechanical data and the scope of the fire declaration must be read again, even if the choice of board was mainly determined by its low lambda. A separate assessment is needed because B-s2,d0 refers to the specified application on steel sheet, not to every free-standing board. Only the complete set of data will allow the distinction between the properties of Eurothane Silver and the assessment of the complete roof system to be maintained. Alongside the thermal results, include the relevant row of the parameter table and the classification conditions corresponding to the designed construction; this ensures that the comparison does not omit the conditions of use.

When ordering Eurothane Silver, the thickness, edge type and covering system must be specified. Visually similar PIR boards may differ in their range of application or in their mechanical properties.

Polyurethane board insulation should have a calculated effect and defined scope of works; include offers covering similarly looking silver boards but different roof systems. The equivalence of a Silver substitute must be assessed through the facing and application in addition to the thermal parameters, so that the cost relates to one comparable result. The material price is only part of the decision, since a similar printed grid does not prove identical suitability for the adopted covering. The final comparison should allow technical equivalence to be checked before comparing amounts per square metre of insulation. Ask for the full name Eurothane Silver, the thickness, the side profile and the scope of works for closing the roof, so that any surcharge has a stated technical justification.