Thermal insulation is one of the most important components of the system on a roof, as it creates a comfortable environment inside the building by protecting it from heat and cold, while helping to reduce heating and cooling energy costs. The importance of thermal insulation has recently increased mainly due to changes in insulation standards worldwide, which place greater demands on the thermal resistance of building structures to reduce energy loss for heating or cooling.
Insulation types used in flat roof systems must have not only high thermal characteristics but also sufficient mechanical properties to withstand loads (for example, snow loads, ballast, limited pedestrian traffic for maintenance, humidity in the construction of inverted roofs, etc.).
Common types of thermal insulation used on roofs
Polyurethane foam (PIR / PUR)
PIR is a thermal insulation panel produced in a chemical process from rigid polyurethane foam (PU) combined with an isocyanate catalyst. This is a very universal and efficient solution for all types of exposed ceilings. It is one of the most suitable insulation types for bonded roofing systems and can also be used in ballast roofing applications.
Advantages of PIR / PUR
Very good fire resistance (over 250 ° C).
Extremely low thermal conductivity value of 0.023 – 0.028 W /m K.
High compressive strength in the range of 100 – 300 kPa, which is also sufficient for some ballast applications.
Lightweight in the range of 30-60 kg /m3.
Rock wool
Rock wool is a type of mineral wool insulation produced from basalt stone fibers. It is one of the most common solutions for mechanically attached exposed roofs, especially where very high fire resistance is required.
Advantages of the Stone Wool
Excellent fire resistance (up to more than 1000 ° C), most rock wool products are classified as non-combustible.
Low thermal conductivity value of 0.038 – 0.041 W/m K.
Compressive strength in the 40 – 80 kPa range, which is sufficient for exposed ceiling applications.
Weight is in the range of 100-200 kg /m3.
Expanded Polystyrene (EPS)
EPS is a thermal insulation panel produced from expanded polystyrene granules. It is one of the most cost-effective solutions for exposed and ballasted roof systems.
Advantages of EPS
Most products are self-extinguishing in fine.
Low thermal conductivity value of 0.037 – 0.041 W/m K.
High compressive strength in the range of 100 – 250 kPa, which is also sufficient for some ballast applications.
Light in the range of 20 – 40 kg /m3.
Extruded Polystyrene (XPS)
XPS is a thermal insulation panel produced from polystyrene in an extrusion process. Due to its special features, it is the ideal solution for inverted ballast systems and utility decks. XPS can also be used in exposed ceiling systems.
Advantages of XPS
Almost no water absorption.
Most XPS products self-extinguish on fire.
Very low thermal conductivity value of 0.034 – 0.038 W /m K.
Very high compressive strength in the range of 250 – 700 kPa, which is sufficient for utility platforms with high traffic.
Lightweight in the range of 25-35 kg /m3.
