Thermano Roof beneath rooftop equipment. What does CS 200 kPa tell you?

Thermano Roof is a rigid PIR board with a gas-tight, aluminium-containing multilayer facing on each side. In CS(10/Y)200, the number gives the declared compressive stress level in kilopascals at 10% relative deformation, or the compressive strength if reached earlier.

TR100 concerns a different loading condition. It indicates a tensile strength of at least 100 kPa perpendicular to the board faces. When specifying PV fixings, the designer checks the fastener, substrate and uplift forces separately. Reaction-to-fire class E applies to the product. The fire performance of the roof depends on the specified assembly.

Suppose one foot carries 2 kN and its flat contact surface measures 20 × 20 cm. The area is 0.04 m², giving an average pressure of 2 kN / 0.04 m² = 50 kPa. This example assumes full, uniform contact over the stated area.

Check the underside of the unit on the installation drawing. A frame resting on two narrow rails has a different contact area from a solid base of the same outer dimensions. If the centre of gravity is offset, obtain the operating reaction at each support. Dividing the total weight equally between the feet can underestimate the largest reaction.

Under sustained pressure, deformation of the insulation can increase over time. The base design needs creep data for the loading period and a settlement criterion. Subtracting the illustrative 50 kPa from the declared 200 kPa does not establish a load reserve.

Where a load spreader is specified, show its stiffness, dimensions and bearing arrangement. Identify which loads pass through the insulation and which go directly into the structure. The top plate dimensions alone do not establish the pressure distribution in the layers below.

Thermano Roof has a declared thermal conductivity of 0.023 W/(m·K). At an example thickness of 120 mm, dividing 0.120 by 0.023 gives approximately 5.22 m²·K/W for the insulation alone. Use the declared resistance for the ordered thickness in the specification and assess metal penetrations separately.

The standard external board size is 1200 × 2400 mm. Set out joints using the cover width of the selected edge profile. This is 1200 mm for BASIC, 1185 mm for TOP and 1190 mm for MASTER. Draw the support footprints on this layout before cutting boards around service penetrations.

Long base rails on a flat roof can cross the drainage path to an outlet. Check the position of the rails, overflows and service penetrations on the roof falls plan. Specify protection compatible with the membrane at each foot and detail any seals required.

A technician needs access to the service panel and space to replace parts. Mark a maintenance route and a temporary set-down area for removed components. Gas-tight PIR facings neither seal penetrations through the roof covering nor protect the membrane from the edge of a tool.

Give the installers a coordinated drawing of the unit, base and roof layers, dimensioned from fixed grid lines. Mark the outlets, fixing points and access zones. If a foot has to move, have the designer reassess its bearing before the detail is covered.

For handover, record the boards, load spreaders, fixings and waterproofing work actually installed. A photograph taken before placing the equipment helps locate board joints and verify membrane protection later. Keep the as-built drawing for a future replacement unit or a change to the PV layout.