How to plan maintenance walkways on an EPS-insulated roof

Start with the access point and mark where a technician must stand to open a unit, remove a cover or reach a drain. A narrow strip beside the equipment may leave too little working space. Coordinate the route with fall protection, inspection points and the roof access plan before traffic establishes a path of its own.

On a new roof, specify the build-up beneath the route from the outset. On an existing roof, establish the grade and thickness of the EPS and the sequence of layers. Where the drawings are incomplete, investigation or a trial opening may be necessary. The appearance of the membrane alone tells you little about the insulation’s resistance to foot traffic.

Investigate soft spots, depressions and uneven areas before covering them. A thicker mat can conceal a defect and make its cause harder to find. Assess a person’s foot, a ladder foot and a trolley wheel separately, since each applies a different pressure to the build-up.

A protection layer can reduce abrasion and the risk of puncturing the membrane. Its ability to spread pressure depends on its stiffness and bearing area. A walkway unit designed for discrete supports needs those supports in their specified positions.

Where a raised walkway or load-spreading slabs are specified, include their own weight and the imposed load. Check material compatibility wherever pads touch the membrane and fit a separation layer if required. Detail edges and restraints so that the assembly cannot chafe the membrane or shift in the wind.

Foot traffic creates short, localised loads. A permanent walkway also bears on the roof between visits. The CS(10) value describes EPS under compression at 10% deformation in a test. It does not establish how many service visits the roof can withstand.

For permanent supports, consider creep and the deformation the roof detail can tolerate over time. A small indentation can change the bearing conditions or collect rainwater. Include temporary handling loads too. Setting down a heavy spare part may impose more local pressure than a person walking past.

Trace the fall of the roof beneath the proposed route, including pads and supports hidden below the walking surface. Water must be able to cross the route where needed. Leave enough space to clear each outlet without having to dismantle a long section of walkway.

Inspect the roof after rain and record any standing water that persists. During subsequent visits check fixings, edges and the condition of pads. A worn pad can concentrate pressure at one point and damage the membrane it was intended to protect.

The operating instructions should show the route, permitted ways of moving tools and places where materials may be set down. State any limits on trolleys or ladder supports in terms a new service contractor can use, even when the original roofer is no longer present.

EPS manufacturers include Paneltech, Arsanit, Genderka and Swisspor. Select the board for the expected use and the documented roof system. At handover, walk the full route, check that outlets remain accessible and examine the membrane for installation damage. A usable route also helps keep traffic off the rest of the roof.