Before building the concrete roof, you will need some careful planning and also a building permit. You will need the advice of a professional on this one. Also you won’t be able to do it alone so get some friends to help you.
Some of the materials that you will need are:
- Steel joists
- Reinforcing bars
- W1.7 wire
- Portland cement
- Concrete slabs
- Work helmets
- Work boots
Safety. You will have to take some safety precautions before you start the job. Make sure you have some safety gear, work helmets, gloves, works, boots.
Joists.The main foundation will be provided by the steel joists. They must be as wide as the entire roof. They should be fixed by a beam or a wall.
Concrete slabs. Now the concrete slabs should be facing downwards, with the opened end facing sideways. The L shaped steel joists will create a flange for the concrete slab.
Grooves. You should find the grooves on the block. They should measure 1/2 inch by 3/4 inches. You will need to place the W1.7 wire into the grooves. It will need to be bent at the end of the row of concrete slabs.
Reinforcing bars. Reinforcing bars will give extra strength to your roof. They need to be inserted through the space between the joists and the slab end.
Grout. The flat roof will be held in place by a grout. The grout mixture is made from sand and Portland cement. Mix one part cement with 2 1/2 parts sand and add water to make a consistent mixture. Then pour the mixture in the spaces between the rows of the concrete slabs. Cover the joists completely.
Repeat this step until you fill the groves with grout to embed the wires and also let the grout to work on the concrete slabs.