Minimum Standards for Structural Design | RCC Structures

Thumb rules for Structural Design | RCC Structures

Design of RCC Structural Components

In this article, we are going to discuss the minimum standards that are to be followed for the design of Structural components of a building such as Columns, beams, slab and foundation. We will also discuss the minimum safe standards for the reinforcing bars that are to be used for the design of the above mentioned Structural Components.

Minimum cross-sectional dimension for a Column: is 9”x9”. But to avoid slenderness ratio problems in multistorey buildings, we prefer a rectangular column design of 9″x12″ which is safer.

Also check out:

Thumb rules for making a Column Layout

Construction on Site | Design of RCC Structures

Construction on Site | Design of RCC Structures

Minimum RCC beam size:  is 9″x9″. But generally, to maintain uniformity and speed of construction, we design all beams of the same size 9″x12″. But 9″x9″ can also be used safely, according to design.

Minimum thickness of RCC slab is 4.5″ because a slab may contain electrical pipes embedded into them which could be 0.5″ or even fatter for internal wiring, which effectively reduces slab depths at certain places, causing cracking, weakening and water leakage during rains. So, a minimum thickness of 4.5″ should be maintained.

Minimum size of foundation for a single storey of G+1 building, where soil safe bearing capacity is 30 tonnes per square meter, and the oncoming load on the column does not exceed 30 tonnes, a size of 1m x 1m or 3′ x 3′ should be used. Even if the load is less (for example only 20 tonnes) then also the minimum is 3’x3′ and depth of footing should be atleast 4′ below ground level if not more…

Reinforcing bar details (minimum)

1. Columns: 4 bars of 12mm steel rods FE 415

2. Beams: 2 bars of 12 mm in the bottom and 2 bars of 10 mm on the top.

3. Slab

a) One Way Slab: Main Steel 8 mm bars @ 6″ C/C and Distribution Steel of 6 mm bars @ 6″ C/C

b) Two Way Slab: Main Steel 8 mm bars @ 6″ C/C and Distribution Steel of 8 mm bars @ 9″ C/C

4. Foundation: 6″ of PCC layer comes first. Over than, a tapered or rectangular footing of 12″ thickness is minimum. Steel mesh of 8 mm bars @ 6″ C/C should be laid. In a 3′ x 3′ footing, this would consist of 6 bars of 8 mm on both portions of the steel mesh.

Those looking for more information on the design of RCC Structures, check out

Guide to Building Design

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  1. #1 by africa web on October 19, 2011 - 2:17 pm

    thanks a lot for the info because it helps us save from dubious consulting fees and it really helps us understand the real objective of construction design which is economy and feasibility.more power

    • #2 by BenzuJK on October 27, 2011 - 4:50 am

      We are glad that our articles have been helpful to you but it is to be remembered that you always consult a local Civil Engineer for the safe construction of your building. Gaining general knowledge about structures will prevent you from getting cheated but do not initiate the construction on the basis of your theoretical knowledge. An expert from the field of Structural Engineering has to be necessarily involved in the designing and construction of the building.

  2. #3 by africa web on November 3, 2011 - 2:56 pm

    sure madam, too good advice not to be ignored. hoping to learn more. once again thanks’. always at your website………………

    • #4 by Ringwang on December 28, 2011 - 3:12 am

      Thank for your kind info. that is really useful for all the civil engineer profession. i am proud of u

  3. #5 by Darman Nayyer on February 9, 2012 - 11:49 am

    Dear Benzu,

    I am very much impress from your articles like one in the link below:

    which seems to be a local project. I do prefab construction on a moderate scale which is not very popular here and therefore also want to diversify into RCC works. Can you please help me in providing structural engineering consultancy for my projects on professional bases? I live in Karachi Pakistan.

    Please let me know as soon as possible if you can help me.

    Darman Nayyer

  4. #6 by lalit kumar Agarwal on April 3, 2012 - 2:59 am

    thank you for providing such a lovely site. your work is really trustworthy.

  5. #7 by Santhosh on April 9, 2012 - 10:44 pm

    Dear madam

    i have seen the apartment towers are constructed by column size 6″ x 18″
    which Standard to refer for this minimum column dimensions?

  6. #8 by gautam on May 11, 2012 - 4:05 am

    madam what should be the thickness of concrete in a foundation and the size of slab for G+2, as i read out that for G+1 a minimum size is 1mx1m and the thickness is about 15 inches is enough.

    • #9 by BenzuJK on May 15, 2012 - 9:44 am

      Hello Gautam,
      All these depend on structural calculations. The loading calculations are very important in this case. The structural design depends on the plan of the building to a large extent. The planning determines the loading conditions on the structure. After having calculated the loads, the quantity of concrete and steel is calculated.
      I suggest you consult a local Civil engineer before taking any step. However, I would like to share a good news with you. We are launching a new business website where people can get their structural design done at minimal rates without having to go through much trouble.


  7. #10 by dr tushar date on May 15, 2012 - 7:12 am

    hello madam,
    i am in the process of construction of my house. please guide me regarding the depth of footing to be taken once the hard strata is reached.
    yoursuggestion is extremely valuable.
    dr tushar date

    • #11 by BenzuJK on May 15, 2012 - 9:36 am

      Structural design is different for structures located in different places. It has to be done accordingly.
      I suggest you consult a local civil engineer for the purpose of Structural design and not do it yourself. This will ensure the safety of your house and your family.
      These articles are mainly for educational and knowledge purpose.
      I hope my suggestion will be taken into consideration by you.


  8. #12 by Basir Ahmad on August 7, 2012 - 11:45 pm

    Hello BenzuJK,
    I am writing you for my own house building and have some questions. I want to build 6 x 14 meters two-story RCC building with concrete Saltbox roof-slab of 4.5″ thickness and 15 columns for building joints. Building is residential with live load of about 750 lbs. please if possible tell me about the Minimum Standards for Structural Design of mentioned building because I am not able to pay for a local civil engineer and I will build mentioned building during 2-4 years to cover expenses for.

    Regards and Thanks,
    From Afghanistan

    • #13 by BenzuJK on December 6, 2013 - 6:30 am

      There are no minimum standards that can be used. Total load on every column has to be calculated in order to design the column and its foundation.

      The load carrying capacity of a 9″x9″ column with 4 bars of 12 MM steel rods upto a height of 10′, with M15 concrete, is 30 Tons. That is the minimum, but in some practices, a minimum of 9″x12″ column is designed for slenderness ration factor. The design depends on a lot of factors, and is not black and white…

  9. #14 by vijay pratap on August 24, 2012 - 2:20 am

    Dear Benzu,
    I have been searching the net for some advice on structural design & it appears u can help me.
    I am trying to build a terrace garden on the roof of my 2nd floor flat in a area of 650 sq. ft.(total area of roof is 1500 sq. ft.). The columns are 10’x9”x15” (16mm-8 pcs & 8mm-4pcs steel), beams are 9″x16″ (16mm & 12mm steel) and the lintel is 125mm thick with 4″ & 5″ steel & is 4″ thick. All are RCC structures.
    I have got done the water proofing of the roof.
    My query is whether the roof can withstand load of 2″ of gravel + 2″ of stone crush sand + 8″ of soil and live load.
    I had consulted a few civil engineers who said yes it can but somehow they could not satisfy me with their reply.
    If u could guide me how to calculate the load bearing capacity of the structure and also please give tentative advice whether the structure can bear load (though i feel i am missing some information that u may require to calculate).
    Many thanks in advance.

  10. #15 by sami on August 26, 2012 - 7:17 am

    i want to know how to take load calculation in beam when there is staircase,inclined beam also

  11. #16 by sami on August 26, 2012 - 7:19 am

    in hollow block slab ,when we provide hidden beam for that load calculation for slab purpose to be taken from center to center

  12. #17 by Abdul on September 25, 2012 - 6:16 am

    Hi Benz!!
    I really find this site educative..I am a new bee in this field..I am now planning to construct a 2-storey residential house with my 25cmX25cm column with 4-20mm rebars is safe? Average distance between column is 3.5m..waiting for your valuable comment..thanks a lot.

  13. #18 by P.Devender Mudiraj on September 27, 2012 - 11:56 pm


    Thank for your kind info. that is really useful for me.

  14. #19 by bevin on October 9, 2012 - 12:55 am

    I am a civil engineer and I am currently planning on constructing a G + 2 bungalow of 3138sq ft ( 1130+ 1258+750). I have done a trial pit for the foundation depth. there is 2 ft of black cotton soil and there after the strata changes to a brownish soil mixed with stones
    I will be doing soil testing in a lab.
    Can you advice me what is the safe bearing capacity required for a RCC framed structure, having columns and footings with slabs
    Thank You

  15. #20 by george on December 1, 2012 - 3:27 am

    pls wat is G+1

    • #21 by BenzuJK on July 26, 2013 - 7:08 pm

      G+1 means ground floor + 1 (First floor)

  16. #22 by rephart on June 6, 2013 - 10:18 am

    pl give me details for constructing a large rcc undergound tank, 500 kilo litre, for our community to collect rain water.

  17. #23 by Fayyaz on November 6, 2013 - 10:42 am

    awesome effort……….like it

  18. #24 by John Mathew on March 3, 2014 - 2:54 pm

    Dear Sir/Madam
    I am planning a double storey in 2200sft (GF~1400 and FF~800). Architect has given the following foundation: 20cm PCC bed concrete/60cm Rubble masonry (upto Ground)/then 45cm rubble masonry and 12cm Plinth beam RCC upto Plinth. Load bearing clay brick walls for super structure. The lintel beam is also of 12cm depth. My doubt is whether we should go for 15cm plinth beam and lintel beam instead of 12cm beams? Is 12cm sufficient or 15cm thickness better.
    The soil is lateritic
    John Mathew

    • #25 by BenzuJK on March 20, 2014 - 5:56 pm

      Hello John,

      I am not trained to design load bearing structures. So I wouldn’t know for sure. But bigger is always better, so you could use 15cm plinth and lintel beams instead of 12cm to be on the safe side.

  19. #26 by uday on August 6, 2014 - 7:03 pm

    i have one industrial purpose shed and have 9*16 pillar (4+4)
    height is 18 feet and thay keep just steel roof no concrete slab now i want slab of 6 inch on it and want further one floor on it size of shed is 17*40 feet
    please do guide me if you reply i ask further more i like to ask about changes i need to do

  20. #27 by P,K,Parameswaran on October 30, 2014 - 2:06 pm

    Thank you. Looking for some good aparment under construction, I located the multi-storeyed “Prestige Downtown” in progress in Vembuliamman koil street, West K.K. Nagar, Chennai. 78. The columns in superstructure have a uniform slender sectional dimention of 6”x24″ throughout. CMDA approved plans are not kept at site. Only, the builders plans for construction is available. i felt this is not in conformity with the Indian standards. i wish to be clarified on the following to enable me to proceed further:
    -Is it approved by CMDA?
    -has it been verified at site by CMDA?
    -are the set-back conditions as approved?
    -is check by CMDA on the dimentions and quality of construction happening as per norms?
    i shall be much obliged for a prompt reply.-

  21. #28 by Manoranjan Behera on January 19, 2015 - 4:39 pm

    Dear sir, i am constructing building of 1600 sq ft with 20 column ,maximum column distance is not more than 12 to 14 ft, for slab 01 eng is suggesting to use both side 8mm Tata rod & other is suggesting one side 10mm rod and other side 8mm rod, this is ground floor slab i want to make G+1 floor, can you inform me which one right.

    • #29 by BenzuJK on February 18, 2015 - 1:02 pm

      What are the axial loads and bending moments acting on your columns? Please design according to that. Personally, in my designs, the minimum steel rods used are of 12 mm diameter. Strong columns are essential for the longevity of the building. Also, please hire good engineers who know what they are doing.

  22. #30 by AL AMIN on March 12, 2015 - 4:13 pm

    I would like to make G+1 (25’x28′)=700 sft 4nos shop and to be 10″x10″ column. So, please let me know how many column I can provide?

  23. #31 by AL AMIN on March 12, 2015 - 4:20 pm

    Dear madam,
    For 700 sft I would like to use 9 nos column 4-T12mm bar is it anougth for G+1 mini store?

  24. #32 by Rahul Pawar on April 3, 2015 - 7:18 pm

    Hello mam
    myself rahul i took land and its water logged area i want basement and ground floor to be constructed so what are the precautions should be taken before and after construction.

  25. #33 by Ifteqar Ahmed on April 14, 2015 - 11:33 am

    Thanks a lot. I felt very much satisfaction after gone through your site..i found many clarifications. Good regards Ifteqar Ahmed civil Engineer

  26. #34 by Ifteqar Ahmed on April 14, 2015 - 11:44 am

    Sir Some authors mentioning the safe bearing capacity of clay soil 25t/m2 and some one 30t/ is confusing pl guide me.thanks

  27. #35 by furquan on April 21, 2015 - 3:26 pm

    I want to know about your site because i have to design the structure for my project which is an apartment.
    As I’m an architect i always need structural designers for my various projects.

    • #36 by BenzuJK on July 15, 2015 - 5:34 pm

      Hello Ahmad,
      Since you are an architect, you do understand that civil engineering is a technical field. It is always recommended that we get our homes designed by civil engineers in order to avoid structural instability that might result.
      I am an Architect and a planner. I have Civil engineers in my team which is why I understand the complexities of structural design. Although there are projects which I can do myself, I still prefer getting it done by structural engineers. It just gives me 100% confidence that this cannot go wrong. Do get in touch if you ever need help.

      Kind regards,

  28. #37 by SV JAYARAMA on May 2, 2015 - 10:18 pm

    How much quantity of 16mm and 12 mm steel rods ( indus make ) required for 8″ x 18″ column for 4 story commercial building.
    pl reply for my email

  29. #38 by Durai Raj on May 19, 2015 - 12:38 pm

    My residential construction is going on. In our building Column beam is closed in ground floor and our engineer advice us for first floor Column beam is not required. Is it advisable one?

  30. #39 by Durai Raj on May 19, 2015 - 12:41 pm

    My residential construction is going on. In our building Column beam is closed in ground floor and our engineer advice us for first floor Column beam is not required. Is it advisable one?

    Durairaj. G

    • #40 by BenzuJK on July 9, 2015 - 9:08 pm

      Of course it is required if it is column and beam structure and not a load bearing one.

  31. #41 by Saravanan S on May 20, 2015 - 9:37 am


  32. #42 by rajeev on June 23, 2015 - 7:18 pm

    Sir the distance b/w my pillar column is 16ft and column is 12*9 and steel bars are of 12 mm 6 in no is it safe my house
    Built Area is 2400sqft

    • #43 by BenzuJK on July 9, 2015 - 8:58 pm

      It is poorly designed I must say… But it should be okay as long as no earthquakes occur.

  33. #44 by sonny on August 16, 2015 - 3:37 pm

    Sir, I just started my construction project occupying a surface area of 13 * 19= 247sqm. G+1…The upper floor is comprised of four studios ( each is made of a sitting room, bed-room,kitchen and toilet). The columns are 30 ( supporting pillars) and 4 veranda pillars for the ground floor ( total of 34). Each column is 9*9 inches containing 6 10mm steel rods. Foundation on a dry area with foundation blocks filled with mortar and all foundation edges bound together with 10mm steel rods. Advice if the design is solid enough to withstand adverse conditions. Thanks.

  34. #45 by Muhammad on September 10, 2015 - 11:03 am

    I want to construct a flat slab mean slab without beam of 3″ thickness. is it safe over 12*15 ft covered area.

  35. #46 by Ravi on September 30, 2015 - 7:39 pm

    Hi Benzu,

    Thanks for the valuable information which is very very helpful for individuals like me. It helps me to evaluate the structural design given by my architect is as per standards or not. I am constructing a G+2 Building in 30*50 site. The distance between the columns is 26 feet and my architect suggested to use 9*15 columns. Can you please let me know if that is fine and how far is it safe? Thanks for your time………

  36. #47 by jaypal mirani on October 2, 2015 - 4:18 am

    I wants to construct rcc shade 22’×20′
    What will be the colum size and its steel detail
    and beam size?

  37. #48 by Yog on November 27, 2015 - 4:48 pm

    I have a house with 29 pillars (plus 2 brick pillars) of 9″x12″ spread over an area of approx 3200 sft in an hilly area. The roof height on the ground floor is 10 sft. I wanted to increase the column height (more than 10 ft) for the roof on first floor. What is the maximum safe floor height for the building?

    • #49 by BenzuJK on December 15, 2015 - 8:45 pm

      It is good that the columns are rectangular, so you avoid the problems that come with slender columns. Use stronger concrete, something like M25 strength concrete for columns, and you could go to 15′ without issues.

  38. #50 by banke pathak on January 16, 2016 - 10:23 pm

    I want to know more about the types of foundations for a multi storage building in areas where suffering from floods

  39. #51 by yashwant gopale on January 20, 2016 - 8:43 pm

    hello mam

    i have newly constructed small bunglow… in the slabs we have used 8mm bars at 6 – 7″cc … is this enough for the slabs?

    and second question is my porch aria slabs is at bottom level of the beam so for the leveling we have filled this area with Brickbat coba around 10″ depth…. is this will over load to the slab or is it ok?

    pls consult about is


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