Flat roof heat insulation

Izolace ploché střechy

Insulation of flat roofs

Appropriately selected materials ensure heat insulation and provide your flat roof with soundproofing and fire resistance properties.



Not only is flat roof insulation required by law. It is also a way to improve the technical parameters of the structure. We at Isover develop and manufacture materials that will help you insulate your flat roof.

Make a choice from our range of mineral wool or polystyrene foam products or go for a complete system solution.

Types of insulation  ➜

What will you get from insulating your flat roof?

 ● Energy saving: a roof with no heat insulation will let out a considerable amount of heat and the insulation will reduce that loss of heat.

 ● Comfortable indoor temperature: heat insulation also plays a role in summer when it prevents the overheating of the interior.

 ● Soundproofing: heat insulation will subdue the sounds coming from outside and the noise generated inside (a shop floor, for example).

 ● Fire resistance: appropriate thickness of the insulation can bring the building’s fire resistance to the required level.

Insulation and soundproofing options for flat roofs

MW skladba - plochá střecha


Using mineral wool (MW)

Basalt wool boards are ideal for insulating flat roofs. This is for several reasons: they are excellent thermal insulators and sound dampers, they are vapour-permeable, water-repellent and non-flammable. Their main applications are in non-walking roofs, but Isover also has solutions for roofs that require frequent maintenance.


Find out more

EPS 100


Using expanded polystyrene (EPS)

Polystyrene is a great heat insulator and has high compressive, tensile and bending strength. It is lightweight and has a high step-on breaking resistance. Isover EPS boards are among the insulators most widely used for flat roofs. In lightweight roofing, EPS needs to be combined with mineral wool to ensure the required fire resistance of the structure.


Further information




Lightweight fire-resistant roofs

Combining the properties of mineral wool and those of foam polystyrene, the special SG Combi Roof system is designed for heat-insulating lightweight trapezoidal sheet roofs. Unlike the mineral wool insulation alone, this system is lighter and has a higher step-on breaking resistance. Builders will also appreciate the favourable cost/performance ratio.


More about the system

Roof Acoustic



Lightweight sound-absorbent roofs

The ideal choice for new hall-like structures is the Isover Roof Acoustic system solution. It has a low weight, high sound absorption and mechanical resistance, which makes the system suitable for sports and manufacturing halls. The system’s insulator is mineral wool or a combination of mineral wool and foam polystyrene. 


Solution details

vegetační střecha


Green roofs

Green roofs have several functions: they prevent indoor temperature fluctuations throughout the year, retain rainwater, subdue noise and refresh the urban environment. At Isover, we manufacture several green roof systems and add to them our own hydrophilic mineral wool. The hydrophilic wool substitutes the substrate to a degree. 


Find out more

How much does insulation cost? Ask us for a free estimate

Our technical specialists will be happy to help you choose the material, calculate the necessary quantity and approximate prices, and will also direct you directly to the nearest dealer.
The service is completely free.



+420 226 292 221


I want advice


Remember the correct pitch

A flat roof must have a sufficient pitch, otherwise there is a risk of water remaining on the surface and this causing other problems. The recommended pitch is 2%. This can be achieved by using Isover mineral wool or foam polystyrene pitched boards (wedges).

We can prepare a layout plan for you.

A layout plan is integral part of every laying job. In order to achieve the best possible combination of a technical solution and the final price, our technical department provides designers, clients and builders with pertinent plans.

This plan and the bill of materials is provided free of charge, usually within 3 working days of receiving complete documents.

The plan clearly shows the final consumption of boards including the pitch and watershed directions. This helps to avoid the incurring of extra costs. After the layout drawing and a quotation are approved by the client or the builder, the pitched boards are immediately ordered and added to production line-up.


Creating the pitch using EPS

Milena Skalská Rejlová – Technical Specialist

📞   +420 602 115 649
✉️   milena.skalskarejlova@saint-gobain.com


Creating the pitch using MW

Roman Jahoda – Market Manager

📞   +420 721 055 812
✉️   roman.jahoda@saint-gobain.com


Please send us the following to receive your pitch design:

 ● your roof’s ground plan and cross-section with dimensions and dimensioned inlet positions as PDF, JPG or DWG file
 ● parapet heights
 ● minimum and maximum heat insulation thickness
 ● minimum roof pitch required
 ● existing roof pitch
 ● type of pitched layer and waterproofing fastening
 ● type of waterproofing
 ● type of designed insulation (EPS, MW) for pitched and base boards
 ● description of the base layers
 ● other information (deadlines, contact persons...).

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