Koster 21 – 20kg (Coverage Up to 7M2 @ 2 Coats)

Koster 21 is a 2 component, liquid applied multi-purpose waterproofing coating, elastic, crack bridging, solvent free – and can be applied to dry or damp and moist substrates.

Koster 21 is liquid applied and therefore seamless. This means that there are no joints which are often a weak point for sheet applied waterproofing system. It also means it’s perfect to apply when there are complicated architectural details.

As Koster 21 can be applied by a brush or roller, it requires less specialist skills for application than a trowel on system.

Koster 21 is typically used to waterproof podium decks, balconies, buried roof and also tricky areas such as external solid stairs.

It’s UV stable and trafficable to light foot traffic. It can therefore be left exposed with a pure brilliant white colour.

Reflects sunlight and reduces building surface temperatures. Suitable for indoor and outdoor use.

Koster 21 is free from volatile organic compounds and does not have a strong odour making it ideal for use near where people are working or living.

We recommend that rounded fillets of Koster Repair Mortar Plus are formed at junctions with upstands before application of Koster 21.

Our guide for selecting Koster waterproofing systems can be found here:

Our guide for buried roof and deck waterproofing can be found here.

Product Data Sheets for Koster 21 Can be found here