Ask The Expert - Insulating A Roof

• Increased insulation performance, particularly when combined with insulation between the rafters.
• Eliminate repeating thermal bridges at structural members
• May increase the thermal mass of the roof
• May also act as a weather resistant layer on the outside of the roof
• May also improve the windtightness of the roof
• Improve the acoustic performance of the building

If moisture were to penetrate the roof during the building stage, due to air leakage or by other means over the life time of a building, it should be able to dry out as quickly as possible so as to offset long term structural, durability and health issues.

When a roof is covered on the outside with an impervious membrane or insulation materials with a high vapour resistance (e.g. foil faced rigid insulation), this significantly increases the length of time required for a roof to dry out.

In our damp humid climate it is desirable to prevent moisture from penetrating the building envelope but in the event that it does, it should be able to dry out as quickly as possible.

In this way, breathable external roof insulation such as Gutex Ultratherm, will provide greater levels of security against moisture accumulation within a roof over the life time of a building.

This depends on the type of insulation installed. Rigid foil faced insulation have a particularly high vapour resistance.

This insulation will substantially decrease the breathability of the roof. Woodfibre insulation such as Gutex Ultratherm is extremely conducive to vapour transfer and is very compatible with a breathable roof.

As the roof within an attic space has a low thermal mass, coupled with the dark tiles predominantly used on our market, these spaces can become both extremely cold in winter and oppressively hot in summer.

Specifying woodfibre external insulation can contribute to ensuring a high thermal resistance is attained in Winter while also provide high levels of thermal mass in Summer, offsetting major fluctuations in temperatures within the living space.

Woodfibre insulation has the optimum combination of high thermal resistance and high thermal mass. This ensures optimum comfort levels within the living space throughout the year.

• Breathable membrane and various sealing agents  
• Gutex woodfibre insulation on both new and existing buildings. 
• We also provide practical and technical training at our Better Building: Fabric First course

For architects and specifiers we provide presentations either at our training centre or by appointment at practices. Contact Us.

CPD presentations can be booked by contacting us. Ecological Building Systems are always available to help guide building professionals through design detailing, products and advice on installation.