ISOVER Polterm Max Plus

ISOVER Polterm Max Plus non-combustible stone wool slab with a black glass veil on the external side. Certified by the British Board of Agrément (BBA)*, the resilient slabs will provide thermal and acoustic insulation within ventilated rainscreen cladding and overcladding systems. The stone wool insulation is non-combustible, achieving a Euroclass A1 Reaction to Fire classification, according to BS EN 13501-1.

U-value Calculator
Start your U-value calculation >
Use the calculator


When specifying the exterior of the building, it's important to ensure that the facade looks perfect, but that underneath needs to be an insulation product that you know works best for your project.

With ISOVER Polterm Max Plus, it's one big plus after another as this insulation solution boasts a range of features which make it ideal for rainscreen and masonry façades.

The stone wool insulation offers both thermal and acoustic benefits, whilst also being BBA certified (19/5672) and achieves a Euroclass A1 Reaction to Fire classification (according to EN 13501-1).

Polterm Max Plus also contains a water repellent additive to limit water absorption. What stands out though is the black glass veil, contributing to the aesthetics of the installation, as it prevents any ‘show through’ of the insulation from behind the façade system.


With a thermal conductivity o 0.035 W/m.K, Polterm Max Plus will help reduce heat loss within the building envelope and decrease energy costs*. Slabs can be tightly butted together and the inner face will accomodate substrate irregularities to maximise thermal performance in situ. 

*If you have a requirement for detailed U-value calculations, please contact your sales represenative.


Poltern Max Plus is a non-combustable stone wool insulation. It achieves a Euroclass A1 Reaction to Fire classification, according to BS EN 13501-1.

Water repellent

Polterm Max Plus contains a water repellent additive to protect against moisture ingress. 


Polterm Max Plus will help improve the acoustic performance of the external envelope, reducing unwanted external noise such as weather, aircraft, vehicles and trains.

Polterm Max Plus has been certified by British Board of Agrement (BBA)*. It is manufactured to Quality Management Standrad BS EN ISO 9001. It is CE marked under the Construction Products Regulations and according to the product standard EN 13162.

ISOVER Polterm Max


Key Considerations

When using Celotex or ISOVER products, you need to satisfy yourself that use of the product meets all relevant national Building Regulations and guidance as well as local, national and other applicable standards relevant for your construction or application, including requirements in relation to fire and applicable height restrictions. In addition to the product datasheet, please refer to the following product documents:

Celotex products should not be used in the external walls of buildings over 18 metres in height (England and Wales) or 11 metres in height (Scotland). Recent changes to Building Regulations mean that only non-combustible insulation or insulation of limited combustibility can be used in buildings of that height.

The building detail is for illustrative purposes only. It does not constitute advice and should not be relied upon.

CPD Opportunity

Our Stone mineral wool insulation for rainscreen and masonry façades is a CPD dedicated to our façade insulation systems. Book here!