Concrete roof decking, processes,advantages and disadvantages

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

An architect with decades of experience


  1. I will raelly need to stay in line with you on issues of building pricing. Like a normal duplex building with a living room at the top and three rooms recreation room and downstirs with one living room, and one room with kitchine, washing room and store

  2. Great job, please i need an advise on this issue. Am thinking of using interlocking tiles or use concrete to do the flooring of my compound. Which on is better, durability and cost efficient ?

  3. How can we stop people like Mr Tunde Amoje a director he called himself, his company called AMO WOOD TECH-NIQUE WORK, HIS OFFICE IS AT IBIWOYE PLAZA,BEHIND, AGO-OKOTA. HIS TELEPHONE IS 08029972749. not to continue coning innocent people like myself. This man Tunde Amoje is a Roque and a person who make me to believed, his a carpenter. He coned me and collected 30,000 Naira from me and never turned up to executed his duty till today since 2009.

  4. I wouldn’t recommend this kind of roof in the tropical climate except for exceptional design reasons or to achieve a clients demand. To achieve a watertight slab is very expensive and requires patience and a construction technology that is not common among the local builders… I will recommend sloping the slab as a way of reducing the effect of water on the slab…

  5. Good work. Please keep it up. Roofing with concrete roof tiles(not concrete roof decking)should instead be encouraged in Nigeria to save millions of Dollars that is being spent today on the importation of all manners of roofing Sheets/Tiles and create employment.It has more advantages and less disadvantages than Concrete roofing tiles.It involve nearly 100% local materials. Please do a publication on this urgently.

    1. Thanks for the submission. Twice I have been asked to encourage people on what you’ve just suggested, We can write something on it together.

  6. Is there much cost difference in 4 bedroom bungalow and a 4 bedroom duplex(3 bedrooms up and 1 bedroom downstair).I want to build 4 bedroom duplex on 1 plot so that I can have better space as compared to 4 bedroom bungalow. Advise me pls.

  7. I sincerely find this very interesting and educative for someone like me delving into real estate and building business.

  8. Very educative ride on sir. @maxwell there is no way u can compair both, a story buildng ll definitly be more expensive considering d features. Call 07038753255 for advise

  9. A review of my reply of 1.6.12:

    Good work. Please keep it up. Roofing with concrete roof tiles(not concrete roof decking)should instead be encouraged in Nigeria to save millions of Dollars that is being spent today on the importation of all manners of Aluminium roofing Sheets and other types of roofing tiles and to create employment too.Roofing with Concrete Roof Tiles have more advantages and less disadvantages compared with Concrete roof decking.It involve nearly 100% local materials. Please do a publication on roofing with Concrete Roof Tiles urgently.

  10. please can u tell me d cost to build a 2-storey building with 3 bedroom on each floor, also with a concrete roofing.

  11. Good job .Pls is German Floor a must for a storey building .Can i raise the building to Linted before considering flooring.

  12. Arc. Omion please consider doing a publication on Concrete Roof Tiles. Importation of all manners of roofing materials is a big burden on the Nigerian economy. Once the weight of concrete Roof Tiles is factored into the design and it is well done, it can have all the advantages of all other roofing sheets/tiles in addition to the advantages that are peculiar to it.It is nearly 100% local materials and a big boost to the economy-employment, savings in foreign exchange, etc, etc.

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