PURPOSE: To obtain a lightweight and strong sheet-like body for civil engineering and construction by coating the peripheral face of a sheet-like core body of a synthetic resin foamed body with a liq. body prepd. by mixing a cement, an adhesive and water, adhering with a non-woven paper wherein a liq. body is permeated, coating furthermore a liq. body and curing the liq. body.

CONSTITUTION: A sheet-like core body 1 is formed with a synthetic resin foamed body. The peripheral face of the sheet-like core body 1 is coated with a liq. body 3 prepd. by mixing a cement, an adhesive and water. A non-wowen paper 4 is permeated in advance with the mixed liq. body 8 and the peripheral face of the mixed liq. body 3 is adhered with the non-woven paper 4. The outer peripheral face of the non- woven paper 4 is also coated with the liq. body 3. Coating with the liq. body 3 and adhesion of the non-woven paper 4 are successively performed and the liq. body 3 is cured. A sheet-like body wherein three layers consisting of the liq. body 3 and the non-woven paper 4 are integrated in a body on the outer peripheral face of the sheet-like core body 1 is obtd. The liq. body 3 on the inner and outer peripheral faces and the non-woven paper 4 are tightly adhered on the sheet-like core body and strength is thereby kept.