ESHADACH | Breathable membrane for pitched tiled roofs

The ESHADACH range from ESHA (Alfa-Alfa Energy) comprises four synthetic breathable underlay membranes, with weights of 95, 150, 170 and 220 g/m². The structure is three-layered: two outer layers of spunbond polypropylene thermally bonded to an inner microporous polypropylene film. They are manufactured in accordance with EN 13859-1, with a System 3 assessment and a test report from the notified body CSI a.s. (NB 1390).

The ARGYNET View

Where the range really stands out: in its tolerance, not in its breathability.

All modern breathable membranes have a low Sd value — 0.02 to 0.05 m. The difference between 0.02 and 0.03 does not alter a roof’s performance. What does alter performance is how well the membrane holds up on site and over the first ten years.

Here, the DoP figures are remarkable:

Tear resistance 190/230 N — approximately double that of comparable membranes in this category. Tearing is the actual failure mechanism: the membrane is punctured by the nail and the wind enlarges the hole with every gust.

Elongation 55/80 per cent — the membrane stretches rather than tears when the timber moves or the contractor crew pulls on it.

Retention after ageing: 88% of tensile strength (MD), and W1 watertightness which remains W1.

Which version would you recommend? The four weights represent a strength scale, not a vapour permeability scale:

- 95 g/m² — an economical solution, for simple roofs with continuous boarding and a sheltered location

- 150 g/m² — the balanced choice for a standard residential property

- 170 g/m² — the documented version with a public DoP; the safe choice for a design project

- 220 g/m² — exposed locations, roofs without continuous underlay, demanding projects