Foamed polystyrene sheets TENAPORS TERMO PLUSS are an eco-friendly, inexpensive and efficient insulation material for quick laying of water-heated floors. The sheets are made of a porous material with closed pores and flame retardant additives (substances that suppress combustion). They are resistant to weak acidic, alkaline and saline solutions but non-resistant to aromatic and halogen containing solvents, esters, ketones, oils or lubricants (e.g. toluene, solvent, ethyl acetate, acetone, etc.). One side of the sheets has cylindrical grooves for easy and fast arrangement and fastening of heating pipes. The sheets are intended for heating pipes in ∅ 16–18 mm. The top surface of the sheet is laminated with polystyrene film (0.12 mm thick). These sheets may be continuously used as a thermal insulation material at ambient temperatures of up to + 80°C.