Standardization and unification of elements, structure designs is one of the main ways to decrease people resources consumption and summary design cost.In this article standard designs of farms of a covering with 10% slope were developed for 24, 30, 36 meters spans for different combinations of loadings. Calculation of efforts and selection of elements sections was made in the program complex SCAD Office. Further there was revealed the dependence between section thickness, spans and loading and there was investigated a limits of using various standard sizes of the accepted bottom chord connection knot. The designed series of farm designs with a 10% slope for 24, 30, 36 meters spans covers the range of loadings from 1,3 t/m to 3,3 t/m. In comparison with similar farms of a series of Molodechno, has smaller metal consumption due to reduction of the top chord section. Transportation of 12-meter lateral section gets to required category.