PURPOSE: To obtain sufficient strength and non-slip property by a method in which a fiber-reinforced urethane foam layer is integrally formed on the back side of an elastic mortar sheet formed by laminating a mortar-mixed soft plastic material on a sheet base.

CONSTITUTION: A sheet base 2 is placed on a flat mould 1, and an under paint 3 composed of mortar-mixed soft plastic material is laminated on the base 2 and cured to harden it. A design pattern paper 4 is laminated on the paint 3 and a top paint 5 composed of a composite soft plastic material is packed into the blank portions of the paper 4 and cured. The flat mould 1 is then separated to obtain an elastic mortar sheet 6, and the sheet 6 with the paper 4 is inversed, placed on the bottom of a mold frame 7, and supplied with a fiber assemblage 8. An expandible resin raw liquid 9 is applied to the assemblage 8, covered with a cover 10, and pressingly expanded for molding. After it is cured for hardening, the moulded product is taken out of the frame 7 and the paper 4 is removed.