Depending on the installation method, different screws must be used to fix the fermacell® Therm25™ panels in place:

Option 1 with top cover plate:

• For a 10 mm cover plate: fermacell™ drywall screws 3.9 × 22 (or special expansion staples of the same length)

• For cover plates > 10 mm: fermacell™ drywall screws 3.9 × 30 (or special expansion clips of the same length)

• For 12.5 mm fermacell® Powerpanel H₂O as a covering board: fermacell™ Powerpanel TE screws 3.5 x 23 mm (or special expansion clips of the same length)

Option 2 with a cover plate on the underside:

fermacell® Powerpanel H₂O screws 3.9 × 35 or special expansion staples (staple length

approx. 32–35 mm)

Option 3 does not require any screws.

Detailed installation instructions can be found in the document: fermacell® Therm25™ Underfloor Heating Elements – Planning and Installation

Yes, fermacell® Therm25™ panels are suitable for damp rooms in water exposure classes W0-I, W1-I and even W2-I.

In zone W1-I, the surface must also be fitted with a suitable waterproofing membrane. When using fermacell® Therm25™ elements in zone W2-1 (high moisture exposure), the surface must be covered with a layer of fermacell® Powerpanel H₂O and sealed accordingly. This is only possible with installation method 1.

Detailed installation instructions can be found in the document: "fermacellTM Therm25™ Underfloor Heating Elements – Planning and Installation"

Yes, it can be used in damp areas (up to W2-I in accordance with DIN 18534) as the top layer of macell® Therm25™ screed elements.

In damp rooms where fermacell® Therm25™ screed panels are not used, the fermacell® Powerpanel TE screed panel should be used.

The fermacell® Therm25™ panel combines a load-distribution layer and underfloor heating in a single system.

There are three installation options:

In variants 1 and 2, an additional fermacell® gypsum fibreboard is used to complement the system; this is glued and screwed or stapled in place as an extra layer above or below the fermacell® Therm25™ elements.

Depending on the required dead load / live load (i.e. the project-specific application), the required thickness of the additional fermacell® gypsum fibreboard may vary.

In option 3, fermacell® Therm25™ panels can also be bonded directly to a level, load-bearing substrate without the need for additional fermacell® gypsum fibreboard.

Option 1:

Covering on the top with an additional fermacell® gypsum fibreboard, fully bonded and secured to the fermacell® Therm25™ panel

Option 2:

An additional fermacell® gypsum fibreboard is installed on the underside; the fermacell® Therm25™ panel is then bonded and secured over the entire surface

Full-surface filling on the top surface

Option 3*:

The fermacell® Therm25™ panel is bonded over its entire surface to a level, load-bearing substrate. The top surface is then skim-coated over its entire area.

* Note: The fermacell® Therm25™ panels do not improve the acoustic or fire insulation properties of the exposed ceiling

Detailed installation instructions can be found in the document: "fermacellTM Therm25™ Underfloor Heating Elements – Planning and Installation".

No. The fermacell® Therm25™ element combines a load-distribution layer and underfloor heating in a single system.

The system incorporates a fermacell® gypsum fibreboard, which is glued and screwed or stapled in place as an additional layer above (Option 1) or below (Option 2) the fermacell® Therm25™ elements.

In option 3, fermacell® Therm25™ panels can also be bonded directly to a level, load-bearing substrate without the need for additional fermacell® gypsum fibreboard.

Detailed installation instructions can be found in the document ‘fermacell® Therm25™ Elements – Planning and Installation’.