Strength for handling and fitting
The woven fabric gives the membrane strength when it is handled and fixed beneath the roof tiles.
20+ years*
Projected durability at 25°C
*The STACS assessment projects approximately 20.4 years at 25°C before the membrane’s pulling strength along its length (machine-direction tensile strength) falls to 50% of its starting value. This estimate uses accelerated heat-ageing results and the report’s modelling assumptions. It is supporting durability evidence, not a service-life guarantee.
Ecolay Roofing Undertile Membrane
Ecolay sits beneath concrete roof tiles, adding an extra layer of protection against water that gets past the tiles.
Ecolay combines a woven plastic fabric with a laminated coating. It is supplied in rolls that can be cut to suit the roof layout.
Use Ecolay beneath concrete roof tiles on new homes and other buildings where an undertile membrane is required.
When tiles are being lifted or replaced, it is a good time to check the membrane beneath them. Ecolay can be used where a new undertile layer is needed and is suitable for the roof.
Your roofer can confirm the requirements for your project. Damax can help with product information and supply enquiries.
The woven fabric gives the membrane strength when it is handled and fixed beneath the roof tiles.
Tests measured how well Ecolay resisted tearing around nail fixings, where the sheet can be put under strain.
The tested material kept almost all its original pulling strength along its length after the laboratory heat test.
No leakage was observed through the sample during a 24-hour water test.
The September 2026 STACS assessment covers Ecolay 5070’s strength, resistance to tearing and ability to resist water passing through. It also uses the heat-test results to estimate long-term durability.
After 72 hours at 82°C, the membrane retained approximately 98.6% of its original pulling strength along its length. Tests across its width also showed no drop in strength.
Heat test: 82°C for 72 hours
The test measured the force needed to tear the sheet around a nail: 579.86 N along its length and 512.18 N across its width.
This test was carried out before heat ageing and was not repeated afterwards.
The test used a one-metre-high column of water above the membrane. No leakage or visible water penetration was observed during the 24-hour test.
Water column: 1 m · Test duration: 24 hours
These results apply to the tested Ecolay 5070 sample under the conditions described in the report.
Read the full results, including the heat-ageing tests and the calculation behind the durability projection.
Download Performance AssessmentSee how Ecolay performed in fire testing. This download includes the fire test results and rating, along with the other Ecolay reports.
Download Fire Test & Product ReportsEach roll contains 43.2 m² of membrane. The roof area it covers will be smaller because the sheets need to overlap and may need trimming. Allow for overlaps, cutting and roof details when calculating how many rolls you need.
No. The tiles remain the main roof covering. Ecolay fits beneath them as an extra protective layer.
STACS used heat-test results to estimate how the membrane’s strength could change over time. The projection is approximately 20.4 years at 25°C before its pulling strength along its length falls to 50% of its starting value. Actual roof temperatures and conditions vary, so the figure is a durability estimate, not a guaranteed lifespan.