Tulppa® is a new type of waterproofing panel for wet rooms developed by Finnfoam Oy. Tulppa® is a horizontally installed wet room panel, which functions as both a construction board and waterproofing material. The core of the panel is made from a closed-cell, waterproof and mold-proof FINNFOAM (XPS) insulation panel and the surface layer consists of strong, special-purpose cement mortar

Due to the patented installation system, the Tulppa® panels with a rabbet profile are quick and easy to install. A professional fitter is easily able to complete 10–15 m2 of waterproof wall surface ready for tiling per hour. Tulppa® is quick to install, easy to work with, and light to handle. The panels’ innovative and patented horizontal installation method makes installation easier and the rabbet profile ensures waterproof seams. The system saves a significant amount of time, as it eliminates the need to apply waterproofing and to wait for it to dry. Tulppa® wet room panels are ready for tiling in less than a day!

Tulppa® wet room panels are also excellent as construction boards in wet rooms and can be used to build shower walls, shelving, benches, or enclosures for a bathtub, for example. Tulppa® panels can also be used to construct the specific solutions mentioned above into existing wet rooms.

Click here for the Tulppa® website, where you can find installation instructions, structural diagrams, and the technical specifications of the panel and systems:


The core of the Tulppa® panels is made from FINNFOAM, i.e., extruded polystyrene, which is a waterproof and mold-proof material with a high thermal insulation capacity. No bromine compounds or other environmental toxins are used in the production of FINNFOAM. The FINNFOAM material and Tulppa® panels carry the M1 emission rating for best quality of indoor air. The surface of the panel is covered with a special-purpose cement mortar, which is reinforced with a fiberglass mesh. The panels can be attached to all foundations.

Panel size (mm)600 x 2600
Panel thickness (mm)
Flat edge12,5
Rabbet20, 30, 50 ja 80 
Short-term compressive strength250 kPa
Thermal conductivity λ Declared 12.5 mm, 20 mm, and 30 mm0,033 W/mK
Thermal conductivity λ Declared 50 mm0,035 W/mK
Thermal conductivity λ Declared 80 mm0,037 W/mK
Absorption of water (FINNFOAM core)< 0,7 t%
Water vapor permeability kg/(m s Pa)˂1,5 x 10ˉ¹²
Fire classNPD
Thermal expansion coefficient0,07
Service temperature5 … +75 C°