Njerwa ndi zida zomangira zodziwika bwino, ndipo zimagwiritsidwa ntchito kwambiri m'magawo ambiri. Monga imodzi mwa mafupa omanga, kufunikira kwa njerwa kukukulirakulira pang'onopang'ono. Inde, njirayi ndi yosasiyanitsidwa ndi kugwiritsa ntchito makina opangira njerwa. Ndi ver
Mipiringidzo ya konkriti imagwiritsidwa ntchito makamaka kudzaza mawonekedwe apamwamba a nyumbayo, chifukwa cha kupepuka kwake, kutsekereza kwamawu, mphamvu yabwino yotchinjiriza, ogwiritsa ntchito ambiri amakhulupirira ndi kukondedwa. Zopangira zake ndi monga mvuvu: Simenti: simenti acts a