In an old times people used acrow props as a pillar which are mostly made up of wood to stand up their roof than they started to make acrow props by several stones to stronger the pillar and to made or several storied building. Gradually

Every construction material is important. It is only when all of them are in the highest quality and in the best possible condition that we get to create a safe and strong structure. While every construction material is important some are highlighted among others as