The GOAT: 344% Stretch, Crack-Bridging and a Cool-Roof White
The GOAT: 344% Stretch, Crack-Bridging and a Cool-Roof White
If you have read the ETA content on the product page, this post goes a level deeper into the numbers behind The GOAT — a flexible, solvent-free, liquid-applied waterproof coating for roofs and balconies. The short version: it stretches, it bridges cracks well beyond what the standard asks for, and the white version keeps roofs cool. Here is the detail.
CE-marked, with a 25-year working life
The GOAT is CE-marked via a European Technical Assessment, ETA-25/0471, issued by ETA-Danmark under EAD 030350-00-0402. The assessment declares a 25-year working life (use category W3), which is the top durability category for liquid-applied roof waterproofing kits of this type.
For external fire, it is classified BROOF(t1) to EN 13501-5, tested by Warringtonfire — the performance class commonly specified for roof coverings exposed to external fire.
Watertight under pressure 💧
Waterproofing is the whole point, so the test matters. The GOAT is watertight with no mass uptake at 150 kPa water pressure to EN 14891 — meaning it neither leaks nor absorbs water even under sustained hydrostatic pressure. For flat roofs, balconies and areas prone to ponding, that resistance to water uptake is what keeps the coating stable over decades.
Crack-bridging well beyond the standard
Substrates crack — thermal movement, settlement, timber deck deflection — and a waterproof coating has to span those cracks without splitting. The standard requires crack-bridging of 0.75 mm. The GOAT is measured at 1.15–1.84 mm, comfortably beyond the requirement across the tested conditions.
That headroom is what gives confidence on real roofs, where movement rarely matches laboratory ideals.
344% stretch — it moves with the building
The reason it bridges cracks so well is its elasticity. To EN 527-3, The GOAT records an elongation at break of around 344%, with a tensile stress of 1.35 MPa. In plain terms, the cured film can stretch to well over three times its length before it breaks, and it does so at a low stress — so it flexes and recovers with the structure rather than resisting movement and tearing.
Vapour behaviour
The GOAT has an ETA-declared vapour Sd of around 1.5 m. This should be accounted for in the roof build-up when assessing interstitial condensation risk, as with any waterproofing layer.
Adhesion — new build and refurbishment
Adhesion is measured to EN ISO 4624, and the results split into two useful groups.
On common construction substrates, bond strength is strong:
- Metal — ~1.17 N/mm²
- CLT — ~1.17 N/mm²
- Plywood — ~0.99 N/mm²
For refurbishment, where you are overcoating an existing single-ply or felt roof, it also bonds to the membranes already up there:
- PVC — 0.32 N/mm²
- EPDM — 0.32 N/mm²
That makes The GOAT a practical option for overcoating tired single-ply and felt roofs without a full strip-off — a seamless liquid layer bonded straight over the existing waterproofing.
The cool-roof white ☀️
Colour is not just cosmetic on a roof. The GOAT White is a cool-roof coating with a solar reflectance of 83% and a Solar Reflectance Index (SRI) of around 104. By reflecting the majority of incoming solar radiation, it reduces heat gain through the roof — easing cooling loads below and lowering surface temperatures on the membrane itself.
Crucially, that reflectance holds up. After 4,000 hours of accelerated UV ageing, measured at Buildwise, the reflectance and SRI are essentially unchanged — so the roof stays reflective rather than losing performance as it weathers.
The technical picture
Put together, The GOAT is a coating designed to move, seal and last:
- Flexible — ~344% elongation at 1.35 MPa.
- Crack-bridging — 1.15–1.84 mm, versus 0.75 mm required.
- Watertight — no mass uptake at 150 kPa.
- Durable — 25-year ETA working life, BROOF(t1) external fire.
- Cool — 83% solar reflectance, SRI ~104, stable after 4,000 h UV.
Whether it is a new balcony deck, a CLT roof, or the refurbishment of an ageing single-ply roof, the numbers point to a coating that flexes with the building and keeps water out.
See the product page for The GOAT, or review the full test data & certifications.