UNILIN Utherm Roof LE on a hall roof: planning insulation around rooflights

Show the deck, falls and finished waterproofing level in section. Read off the available upstand height at the kerb and at the parapet. If the roof rises towards the rooflight, the tightest point may be on the high side of the kerb.

Unilin gives a declared thermal conductivity of 0.022 W/(m·K) for Utherm Roof LE. The data sheet lists a thermal resistance of 4.50 m²K/W at 100 mm. These values apply to the PIR board with laminate on both faces. Use the declaration for the board being ordered.

For heat-loss calculations, distinguish the opaque roof from the rooflight openings. Provide the total kerb perimeter so the designer can account for linear junctions. Two halls with the same roof area can have very different total junction lengths.

Start the cutting plan with the actual outside dimensions of the kerbs. The nominal opening in the structural deck may be smaller. Drawing both outlines shows where support ends and how much room remains for a full joint between adjacent boards.

If the drawing leaves a narrow strip along every kerb, try shifting the starting row. Check what this does at the opposite parapet as well. The accepted joint arrangement and support for cut boards should follow the system instructions.

Specify the membrane type and attachment method. For bonded systems, check the permitted substrate and preparation of the laminate in the system documentation. Mechanical fasteners require a layout for the actual deck and wind load zones.

At the kerb, mark where attachment to the roof surface ends and attachment to the vertical face begins. Inspect corners and membrane terminations before closing the detail. Flashings can make those areas difficult to access later.

Roof LE has a declared compressive stress of at least 150 kPa at 10% deformation. Designing a support for an air handling unit requires further information, including the reaction at each foot, the contact areas and the duration of loading.

Mark the maintenance access route on the roof plan. Check whether the route requires protection over the waterproofing and whether the underlying assembly can carry its design loads. Check the fire classification for the actual roof build-up and attachment method.

A 1,200 × 600 mm board covers 0.72 m² and a 2,400 × 1,200 mm board covers 2.88 m². In theory, 28.8 m² of rectangular roof takes 40 small boards or 10 large ones. This assumes full use of the board area and allows no cutting waste.

Prepare a separate piece count for the rooflight strip. Allow for offcuts that fit the next bay and the handling and cutting cost of the larger format. Specify thickness, edge profile and unloading point when obtaining a delivery price.

Select two adjacent rooflights and lay a trial bay to the drawing. Record whole boards, reusable offcuts and cuts that needed adjusting. Where the spacing repeats, use the corrected cutting plan for the following rows. Take off the final bay at the parapet using its own measurements.