Civil Engineering/concrete slab


We have a G+1 house the walls are 240mm brick wall (external) and 120mm brick wall (internal) we need to have an adequate concrete slab the slab will be held by the walls (No columns or beams) the spaces between walls varies and the maximum span (6.5m * 4.5m).

Now would you suggest a proper slab thickness? and whether we need a bounding beam underneath the slab or not?

And typical steel reinforcement for the slab (detailed)?


Hi Dzaie,

If the slab can be 2-way spanning, I would suggest a thickness of 200mm and you should have a 200mm downstand (i.e. 400mm deep overall by 240mm wide) periphery beam sitting above the external walls to act as ties and lintols over windows, doors, etc.

The rebar design depends on several factors (materials, loading, exposure, etc)so I would suggest you get a local engineer to design and detail that for you as I do not offer that service over this forum.

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Arshad Khan


I can answer any questions to do with civil and structural engineering consultancy and construction industry in East Africa and the Middle East, and specifically with the analysis and design of reinforced concrete structures. My particular expertise is in the aseismic design and optimisation of tall buildings.


Employment history: 40 years in Construction and consultancy in the UK, Kenya, Tanzania, Uganda, Ethiopia, Eritrea, South Africa, Somalia, Zambia, Austria, Bahrain, Kuwait, Doha and the U.A.E.

.Fellow of Institution of Structural Engineers (UK) .Fellow of Institution of Civil Engineers(UK) .Member of the Institution of Engineers, Kenya .Registered Engineer, ERB, Kenya .Member of the Architectural Association of Kenya (Engineers Chapter) .Chartered Engineer (UK)

•1984: International Conference on the Art and Practice of Structural Design, London •1994: 3rd Int. Kerensky Conference in Structural Engineering, Singapore •2008: International Conference on High-Rise Towers, Abu Dhabi •2013: IEK International Conference, Kisumu, Kenya

BSc, 1st Class Hons, in Building Engineering, University of Bath, UK MSc in Concrete Structures and Technology, University of London. Diploma of Imperial College, UK.

Awards and Honors
•Science Congress Special Award (for 2-seater Hovercraft - 1968) •Institution of Civil Engineers Award for outstanding performance at Bath University (1975) •Concrete Society Postgraduate study Bursary Award (1976) •Consular Representative for British High Commission, Nairobi. (1995 to 1998) •Examiner for Institution of Civil Engineers Professional Interviews, Nairobi. (1997 to 1998) •Branch Representative in Vienna for PI assessment for Inst. of Struct. Engrs. (1999 to 2010)

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