Good roof insulation is essential to ensure a building not only complies with Building Regulations, but also achieves the desired thermal performance to ensure the comfort of its residents and energy efficiency of the building. The natural flow of rising heat, and the more exposed position of a building’s roof to the elements, means heat loss is prominent through uninsulated roofs, so roof insulation is an important consideration in the building design.

Whether it’s a new build, retrofit project, or when converting a loft or attic space, installing high performance rigid Mannok Therm Floor / MF insulation boards can significantly improve the thermal performance of the space, and therefore the entire building, enabling specifiers to achieve excellent U-values.

A key consideration in the building design phase for new build or retrofit projects is the positioning of the insulation. Firstly, will the roof insulation in a pitched roof be laid at the ceiling or the rafters? If the pitched roof insulation is to be installed in the rafters, there are further options: warm roof insulation, or cold roof insulation.

Warm roof construction is where the insulation is positioned above the rafters, and immediately below the roof’s weatherproof membrane. The key advantage of this method is the improved thermal performance. The rafters are positioned inside the insulated envelope of the building, keeping them warm and storing the space’s heat.

For new pitched roof buildings, it is common to opt for the warm roof construction method, and it is also suitable to install warm roof insulation when re-roofing an existing detached building.

When completing a retrofit project, or converting a loft or attic space, this may not be the most cost effective or appropriate method of installing or upgrading pitched roof insulation, as it requires the rooftiles to be lifted to install the insulation boards above the rafters.

PIR roof insulation boards are lightweight and easy to handle and fit. These rigid insulation boards comply to all relevant industry standards and can help achieve excellent thermal performance.

Cold roof construction is where the insulation is laid below the rafters, so the rafters are positioned outside of the insulated envelope of the building and remain cold.

The cold roof method is generally more appropriate for refurbishments and loft or attic conversion projects, as it requires less disruption and cost than installing warm roof insulation in these cases. The layer of roof insulation can be laid below, or between and below, the existing rafters, so for insulating existing pitched roofs, cold roof construction is a much easier solution.

PIR insulation boards, such as Mannok Therm Roof / MR insulation, are widely used for insulating pitched roofs using either the warm roof or cold roof methods thanks to their excellent thermal performance, ease of handling and installation, their strength and durability.