EN 14891 covers liquid-applied waterproofing used under ceramic tiles. A designation like CM O2P looks cryptic but encodes exactly what the product is and what it survived.
Reading the designation
- The first letters give the type: CM is cementitious, DM is a dispersion, RM is a reactive resin.
- O means crack bridging at standard temperature; O1 and O2 mean it was also tested at low temperature, O2 being the more demanding.
- P means it passed the contact-with-chlorinated-water test, which pools and spas require.
The tests that actually decide it
- Initial tensile adhesion of at least 0.5 MPa — this is where poorly dispersed polymer shows up.
- Adhesion after water contact, heat ageing, freeze-thaw and lime water: the ageing set is what separates a real formulation from a cheap one.
- Crack bridging of at least 0.75 mm, measured on a substrate that is pulled apart under the film.
What certification costs and takes
- Expect a full test programme to take six to ten weeks in an accredited laboratory once samples are submitted.
- Send more sample than you think you need, from a batch you can reproduce exactly — a repeat submission costs the same as the first.
- Your own lab should run the adhesion and crack-bridging tests first. Failing in-house is cheap; failing at the notified body is not.
The short version
The ageing tests, not the initial adhesion, are what a serious formulation is designed to pass. Screen for them in your own lab before you spend on certification.