What an ETA Means: Poseidon Wetroom Waterproofing, Certified

What an ETA Means: Poseidon Wetroom Waterproofing, Certified

When you specify or install a waterproofing membrane behind tiles, you are trusting it to keep water out of the building fabric for decades. So how do you tell a genuinely tested product from a tin of "tanking paint" that simply claims to work? One of the clearest signals is a European Technical Assessment (ETA). Poseidon carries one: ETA-23/0378. 💧

What is an ETA?

An ETA is a route to CE marking for construction products that are not fully covered by a harmonised European standard. In plain terms, it is an independent, pan-European technical assessment of a product, carried out by an approved body against an agreed assessment document.

Poseidon's ETA was issued by ETA-Danmark under EAD 030352-00-0503 — the assessment document for the "watertight covering kits for wet room floors and/or walls" product family. Because the assessment follows a recognised European procedure, the product can be CE-marked and specified across Europe and the UK on a consistent, comparable basis.

Crucially, an ETA is not a self-declaration. Poseidon is assessed under AVCP system 2+, which involves an independent notified body and ongoing factory production control — not just a one-off lab result. The assessment assumes a working life of 25 years when the product is correctly installed and maintained.

What the ETA actually declares

An ETA is only as useful as the performance it records. Poseidon's declared characteristics include:

• Watertightness — watertight across the covering, and watertight around penetrations (pipes, drains and fixings).
• Crack-bridging ability — category 1, covering a crack width of 0.4 mm. Real substrates move and hairline-crack; a crack-bridging membrane keeps the waterproof layer intact when they do.
• Bond strength >0.5 MPa, so the membrane stays adhered to the substrate and the tile adhesive keys to it.
• Durability — resistance to water, temperature and alkalinity, each retested with bond strength remaining ≥0.5 MPa.
• Water-vapour resistance — a declared Sd value of 33.65 m.

The tests behind the certificate

The performance in the ETA is underpinned by EN 14891 testing carried out at Buildwise in Belgium, the reference method for liquid-applied waterproofing under ceramic tiling. Poseidon's results include:

• Water impermeability: PASS — no water penetration.
• Crack-bridging at 0.4 mm: PASS, category 1.
• Joint movement: remained watertight through a 2 mm joint-movement test.

For a tiler, builder or specifier, that is the difference between a marketing claim and evidence. An uncertified tanking paint may perform well — but you have no independent, standardised confirmation. An ETA gives you a document you can hand to a client, a building control officer or a specifier with confidence. 🛡️

How Poseidon is built up

Certification only holds if the product is installed as assessed. Poseidon is applied as follows:

• Two cross-applied coats — by spray, roller or brush — building to a dry film thickness of roughly 0.4–1.0 mm. Cross-applying the second coat helps ensure full, even coverage.
• Reinforcement at the details — reinforcing tape or sealant is applied at internal corners, wall-to-floor junctions and around pipe and drain penetrations. These are the points where a wetroom is most likely to fail, so they are detailed and reinforced, not just coated.
• Tiling — once cured, tiles are bonded using a suitable C2 cement-based adhesive.

Follow the build-up and detailing, and you have a waterproofing layer whose performance is backed by an independent European assessment rather than a promise on a label. ✅

The bottom line

An ETA is not a marketing badge. It is an independent, standardised assessment that lets a wetroom waterproofing product be CE-marked and specified across Europe and the UK, with declared, tested performance for watertightness, crack-bridging, bond strength and durability. That is the confidence Poseidon's ETA-23/0378 is designed to give.

See the underlying results for yourself in the full test data & certifications, or explore Poseidon for your next wetroom project.