FIELD: construction engineering. SUBSTANCE: device has at least two guide strips provided with supporting and guiding surfaces and filling knife. Surface elevation in premises is marked for finishing material layer by installing guide strips with their ends on panels abutting against panel being treated, in front of it, with supporting surfaces facing panel in parallel with and at certain distance to each other. Then guide strips are fixed in position when plane formed by supporting surfaces of both strips becomes elevation plane for layer finishing material ensuring desired quality of finish. Elevation plane is marked by line intersecting surfaces of abutting panels. Ends of guide strips are fixed through their supporting surfaces on intersection line and spaced apart; finishing material is applied to panel between guide strips and distributed over panel surface by moving the filling knife over guiding surfaces of strips to form rectangular areas of layer. After layer consolidation guide strips are displaced to other area and operating cycle is repeated as required with guide strips held in desired position. Consolidated surfaces of finishing layer may be used to form guiding surfaces for moving filling knife between them. EFFECT: improved quality of finish. 9 cl, 4 dwg
