Insulating Loft Conversions

Loft conversions insulation

Ballytherm insulation may be used to form warm pitched roofs when applied between and below the rafters.
This method is well suited to loft conversions and refurbishment projects where the roof covering is being retained. The properties of Ballytherm insulation match those required for this application: its low thermal conductivity minimises the thickness of insulation required, whilst it is strong enough to span the distances between the rafters without bowing.

The Ballytherm boards should be set in two layers, one layer between the rafters and the second extending across the underside of the rafters and restrained by battens. The insulation is protected by the internal finish fixed to the underside of the rafters.

The reflective surface of the boards reduce radiation heat loss across the air spaces and further improves the thermal performance of the roof.

The thickness of Ballytherm insulation required to meet regulations may be determined from table 12.

Table 12

Further Advice & Information

For more information about Ballytherm products, technical advice, or guidance on the suitability of our products for your project, contact us at + 353 (0)49 95 27000,, email us at or use our contact form.

Roof Insulation

Design Guidance