FAQs
Answers to the questions installers and builders ask most.
Is Thermasheet waterproof?
The XPS core is 100% waterproof (zero capillary absorption, 0.2% by volume after 2-day immersion). The finished wet area must still be detailed and waterproofed to AS 3740 and the project specification.
Can I tile directly onto it?
Yes. The cement-polymer face is tile-ready. Use an adhesive suited to cementitious substrates; maximum tile loading is 60 kg/m².
What thickness do I need for a stud wall?
10 or 12 mm at 400–450 mm stud centres; 20 mm or thicker at 600 mm centres. 6 mm is not recommended for direct fixing to stud walls.
How do I cut it?
Score and snap thin boards; use a fine-tooth saw or circular/track saw for thicker boards, with dust extraction and a particulate mask.
What screws and spacing should I use?
Corrosion-resistant screws with large washers, at approximately 200 mm centres around supported edges and 300 mm through the field, unless the project detail requires otherwise.
How do I seal the joints?
Fill every joint with Thermasheet MSP Sealant. On framed walls, or under render or microcement, also embed 50 mm fibreglass reinforcing tape.
How tight a curve can I make?
Down to about 50 mm with UltraFlex10, and 300–400 mm with Flex, depending on framing and site conditions. See the Curved boards guide.
Can I use it outside?
Yes, for soffits, facades, columns, outdoor kitchens and furniture, fully encapsulated in an approved finish with flashings and movement joints. Project engineering and NCC assessment may apply.
Is it non-combustible?
No. It has fire hazard indices of 0/0/0/6 to AS/NZS 1530.3, which is not a non-combustibility classification.
Does it help underfloor heating?
Yes. 10 mm board over a slab reduces downward heat loss, so the system warms up faster.
Can it replace villa board or fibre cement?
In many wet-area and feature applications, yes. It is lighter, faster to cut and waterproof through the core.