Waterproofing of a Trafficable Roof with Thermal Insulation & a Single Waterproofing Layer

Solutions & Applications · Flat Roof Waterproofing

A trafficable roof (a flat roof with loose-laid slabs) must be trafficable, thermally insulated and completely watertight — with a single, correctly constructed waterproofing layer. The secret lies not only in the material, but in the sequence of layers: a missing vapour pressure release layer or a careless detail in the parapet is enough to cause blistering, dampness and thermal bridges.

The principle: a single waterproofing layer, done correctly

In the ‘loose-laid slabs – single waterproofing layer – conventional thermal insulation’ system, the waterproofing is not bonded to the slabs but is protected by them, whilst the thermal insulation is laid beneath the membrane. This ensures accessibility, thermal protection and easy maintenance — provided that each layer is installed in the correct position and using the correct technique.

Layering, step by step

From the concrete slab upwards:

1. Substrate primer — ESHATOPRIMER: a primer for bonding bituminous membranes, ensuring excellent adhesion of the waterproofing to a clean, dry slab.
2. Thermal insulation & creating slopes — FIBRANxps 300 for the insulating layer and FIBRANxps INCLINE for controlled slopes towards drains. Bonding of panels with Ceresit CT 84, a low-expansion polyurethane foam.
3. Vapour pressure release layer — ESHAPERFO: a perforated bituminous membrane that allows for spot bonding of the overlying waterproofing layer and the passage of water vapour from below — prevents blistering.
4. Waterproofing layer (single) — ESHADIEN SBS -20: elastomeric bituminous membrane with flexibility down to -20°C and elastic recovery >90 per cent, for crack resistance and long-term waterproofing. In areas requiring cold application or as a first layer, the self-adhesive ESHASTICK PG is also used.
5. Details, parapets & joints — ESHASTICK TUB (self-adhesive waterproofing tapes) and ESHASEALER No1 (asphalt joint sealant) for a watertight seal at terminations, drains and joints.
6. Protective coating — ESHACOAT 6S: a cold-applied elastomeric bituminous emulsion, for protecting and reinforcing waterproofing at critical points.
7. Final surface: cement screed and loose-laid floor slabs, which make the flat roof trafficable and protect the waterproofing.

Why this system?

• Accessibility: loose-laid slabs provide a trafficable, usable flat roof.
• Single-layer system = speed & economy: a properly designed single-layer waterproofing system, without compromising on reliability.
• No blisters: the ESHAPERFO vapour barrier manages water vapour beneath the membrane.
• Cold resistance & cracking: ESHADIEN SBS-20 remains elastic at -20°C.
• Thermal insulation & slopes combined: FIBRANxps 300 + INCLINE in a single solution, with no standing water.

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