URSA 10 Loft Roll and URSA 20 DIVERSO Loft Roll are for use as loft insulation in ventilated and unventilated cold roof spaces.
When used in new buildings or upgrading existing buildings URSA 10 loft insulation is the most cost effective way to reduce heat loss through the roof.
URSA 10 Loft Roll - thermal conductivity 0.044 W/mK.
URSA 20 DIVERSO Loft Roll - thermal conductivity 0.040 W/mK.
To minimise the condensation risk a vapour control layer is required when insulating between the rafters at ceiling level, this can either be a polythene sheet (minimum 500g) or a foil-backed plasterboard. The use of the vapour control layer also creates an air barrier that helps to improve the air tightness of the building and so limit air infiltration. The type of roofing underlay should be carefully considered. Breathable membranes (Type LR) may not require roof space ventilation provided they are covered by BBA certification. More traditional bitumen or polythene based membranes (Type HR) require provision for eaves and ridge ventilation.
The plasterboard ceiling should be sealed at the junction with walls with plaster, adhesive or flexible sealant and around service penetrations using a flexible sealant.
As the loft space remains cold any water services, tanks, pipes and cisterns must be insulated to avoid freezing or condensation problems. Omit insulation underneath water tanks at ceiing level as heat from inside the building will help to prevent the tanks from freezing.
Recessed lighting should be in a sufficienctly large enclosure to ensure continuity of the insulation whilst still allowing heat to dissipate from the lamp. The fixture should be sealed to maintain a vapour tight ceiling and prevent unwanted air leakage.
With increasing levels of insulation it is vitally important to ensure continuity of the insulation around openings and at the junction of elements. Follow the guidelines in the Accredited Construction Details, Accredited Construction Details (Scotland), The Concrete Block Association and Constructive Details (for aircrete blocks).