Decked roof may not give you too many options in terms of design, but it also has its own advantages and quite a few uses decked roof.
Before you decide on using decked roof or concrete slab to cover your structure you must have factor the weight during design process.
In this case we are looking at flat concrete roof.
i-You must factor in the load on the foundation with your structural design/drawing due to extra weight.
ii-The granite chippings should be very small like half inch or less ,the finer the granules/aggregates , the more impermeable to water the concrete becomes, larger aggregates creates too many air pores that can allow water to drip into the inner part of the building.
iii-There should be high cement aggregate minimum should be 1:2:4 but ideally 1:1 ½:3 or less
iv-The mixing process of cement ,sand,and granite should be thorough, using hand mixing is not advisable, the machine should be given time to mix properly and water should also be adequate to have a thorough mix
v-Application of water resisting materials on the surface of the roof deckis important like bituminous felt etc
vi-The bamboo studs and the carpentary formwork must be done near perfect to forestall defects in the concrete decking.
Hence, these are the basic steps-
-Do your formwork
-Apply the iron rods
-Cast the concrete mix with water resisting cement
-Screed the top of the decking with cement and sand and make it slope downwards to the side of building where it can easily be channeled through drainage pipe to gutter or make it have direct fall to the ground.
1-It last longer than any kind of roof
2-It also doubles as a sit out on roof if access is created with staircase to the roof
3-It can be designed to accommodate another floor thereby the roof becomes a higher floor and blocks are raised up, but the additional weight must have been factored in the design.
4-If it is well done leakages are very unlikely for many years to come
1-Conduct heat to the interior especially at night after long hours of absorbing the scorching sun during the day.
2-Maintenance can be problematic if it was not properly done
3-You can’t change the roof style easily without serious structural work which you enjoy with other types of roof
4-No room for multiple design patterns like other styles of roof, therefore you may not achieve much aesthetically