Nhanganyaya:Simbi purlins inoshandiswa pakutsigira kwechimiro muzvivakwa zvesimbi.Kazhinji kazhinji, purlins zvikamu zvikuru zvezvivakwa zvedenga.Roof purlins inotsigirwa ingave nema rafer kana madziro ekuvaka uye denga remba rinoiswa pamusoro pe purlins.