Changes

====Lay the concrete====

* Reinforce lower side of flat slabs as concrete does not work well under tension. Reinforcement can be avoided if making dome shape structures (e.g. cover to rainwater tank, or dome latrine slab).

====Curing====

Ensure adequate curing - this is one of the most important aspects to making strong concrete, but is often bypassed in the field due to lack of water, knowledge or organization. Adequate curing is necessary to keep the process of hydration going as long as possible – the longer the time, the stronger the concrete. This hydration process will stop once the concrete has dried out, resulting a strength of concrete according to the time of curing. Although curing can continue even for years, 7 and 28 days are normally quoted (see graph) – curing should last at least 7 days, if not longer especially in cold weather. Curing involves sprinkling water on the concrete every day as well as covering it, preferably in a shady area. Covering can be done with material like plastic or sacking, but covering in wet sand also works well, as does putting the concrete entirely in water.