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Roofs and lofts

The JJ-IntelliRoof™ is a fully engineered panelised solution for fast onsite erection of a fully decked, insulated, watertight, braced Room in Roof.

JJI-Joists are ideal for use in large, flat roofs where their excellent spanning capability can be used to good effect. Given that most of the heat loss from a building is through the roof, JJI-Joists once again provide the opportunity to insulate this area of the building to unprecedented levels with ease. Roof cassettes up to 12m long can take weeks off the installation time for large, flat roofs.


Roof cassettes can also be produced as an alternative to attic trusses and other time consuming framing arrangements used to construct room-in-roof top floors on houses. This system is independent of the building construction method and can be used with traditional masonry construction or timber frame with equal ease.


The JJ-IntelliRoof™ brings the proven benefits of JJI-Joists to both the floor and roof elements of room-in-roof construction. The system consists of lightweight prefabricated cassettes to form the floor, followed by standard timber frame spandrel panels up to ceiling level. A top hat section is then assembled at ground level and lifted into place on top of the spandrels, resulting in a substructure ready to receive the roof cassettes. The roof cassettes are then lifted into place and fixed to the substructure, using proprietary fixings.

 Combining JJI-Joists with the Simpson JES product provides an innovative alternative to traditional loft conversion methods allowing the structural loft floor to be installed between existing trusses with the temporary removal of only two or three courses of roof tiles to provide access.

Timber Systems Division contact