Except for the basic model option (single sided), all of our models can be insulated. The double sided model options (standard, premium and superior) all have a cavity which will be stuffed with rockwool. Recent studies have indicated that a roof insulation (*) using either glasswool. rockwool or polystyrene foam is not the most effective. A system making use of an air barrier seems far more effective, a system which is based on a minimum required air gap between roof decking and roof ceiling created by longitudinal and lateral crossing furring strips. A special in-house developed roof construction is applied to guarantee the proper insulation index for this system. A correct thickness of the furring strip layer is essential. Too thick or too thin an air gap and insulation will not work. The air gap thickness needs to be exact as to comply with the insulation index parameter which is normally provided in the building codes and may vary from country to country. Prefabworld Bali International has developed a calculation method to define the proper air layer thickness which has been approved world-wide.
(*) Mandatory for all Hawaiian islands
The roof decking built-up with a furring strip insulation is as follows (from top to bottom):
- roof decking material (tiles, corrugated sheating, thatch or wooden shingles)
- battens (only in case of roof tiles)
- rain proofing (3 mm thick hessian asphalt felt)
- plywood with a certain thickness
- upper layer furring strips layer (proper thickness not be be disclosed) (*)
- second layer furring strips layer (proper thickness not to be disclosed) (*)
- layer of radient aluminum foil barrier
- plywood with a certain thickness
- ceiling material
- purlins
- rafters
- truss system
(*) The thickness of the furring strips is crucial and needs to be properly calculated to obtain the optimum air gap and is based on the thermal index (R-value) related to the outside temperatue and inside temperature.
