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How to calculate numbers of blocks from a building plan.

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Most asked question from a would be house owner is always how many blocks do I need to get my building completed. Hence this topic is written with illustrations to make it easy for you to do

the calculations yourself from the plan your architect gave you.
The plan above is for a 2 bedroom bungallow, so we are going to start from the basics having in
mind these factors-
i)The lenght of a block is 0.45m or 450mm or 18″
ii)The width of thickness varies -150mm or 6″ and 225mm or 9″ which are most common.
ii)Taking for a general or average purpose, the blocks laid from foundation to dpc(german or
oversite concrete) is 4 coaches/levels. From dpc to the base of window another 4 coaches,from
base of window to top of window another 5 coaches, then from top of window to base of roof
another 3 coaches, neglecting the lintel or concrete on top of window.
Now with these parameters let calculate the plan above which has a wall of 150mm or 6″ all
through.
Add the length and breadth of the blockwall for external and internal
Therefore (A)9,400mm +9,600mm(B)+9400(C)+9600(D)=38,000mm or 38m
Now add the internal walls too
(Follow the grid lines and check the corresponding dimensions on plan remember 150mm is the
block width)
(Grid 7)150+3600+150+150+3600+150=7,800mm or 7.8m
(Grid 6)1350+150+2250+150+825+675+150=5,550mm or 5.55m
(Grid 1b)800+2400+1300+900+100=5,500mm or 5.5m
(Grid 2)2600+900+100+150+100+900+500+150=5,400mm or 5.4m
(Grid 3)1800+150+650+900+250+900+1450=6,100mm or 6.1m
(Grid 3b-Kitchen)900+50+1200+50+150=2,350 or 2.35m
(Grid 7b toilet)1800 or 1.8m
Total internal walls=34,500mm or 34.5m
Therefore Total walls=38,000mm +34,500mm=72,500mm or 72.5m
Now for the first 4 coaches to dpc level the wall will run right through, i.e the spaces for
doors or windows are not left out (n/b- blocks are used in relatively strong and stable soil not
waterlogged area that requires concrete instead).
Divide the sum by 450mm to know the numbers needed for one level/layer/coach of blocks
72,500/450=161 blocks
From dpc level to roof lets take the numbers of coaches to be 4+5+3=12 coaches
then multiply the numbers of blocks for each coach above by 12
161 x 12=1932 blocks
Don’t forget we have windows and doors spaces which we need to remove,for each window of 1200mm
take numbers of the block to be 14 (i.e 1200/230=5.2 and 1200/450=2.6 ,5.3 x2.6=14 approx
Now count the numbers of 1200mm windows and multiply by 14
Total numbers of 1200mm windows as counted on plan is 12 (note 2400mm window was taken as two of
1200mm window)
i.e 11 x 14 =154 blocks + 7 blocks for 600mm window for toilet. Total=161 blocks
Now calculate for doors,Numbers of blocks for a door of 900mm is 18.
height of a door(2100/225=9)+width of a door (900mm/450mm=2). so 9 x2 =18 blocks for each door.
Multiply 18 by numbers of doors=18 x8=144 blocks
Add 144+161=305 blocks,then remove from total blocks of 644 (for dpc) + 1932
Total numbers of blocks reqd=2,271 blocks
For a quick calculation, having the entire length to be 72,500mm. Take for a bungallow total
lenght from foundation to roof to be 1,200mm +3000mm=4200mm
Then calculate the surface area which is 72,500 x 4200 and convert to meters
72.5m x 4.2m=304.5m2
Remove surface areas of windows and doors
For window, height is 1.2m and total is 11
i.e 1.2m x 1.2m x 11=15.84m2 +0.6 x0.6(toilet window)=16.2m2
For doors, height is 2.1m while width is 0.9m
i.e 0.9 x 2.1 x 8(nos of doors)=15.12
Total area for doors and windows=16.2m2 +15.12m2=31.32m2
Remove 31.32m2 from 304.5m2=273.18m2
Now divide this by surface area of a block which is 0.225 x 0.45=0.10125
The blocks reqd caculated by this method is 273.18m2/0.10125=2,698 blocks
Note a difference of about 400 blocks from the two calculations. Of course you can’t get exactly
the numbers you need but the first method is close to it. And calculations are not 100% true
because of these factors
1-The mortar space was not considered
2-Blocks that will be wasted due to breakages e.t.c

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This entry was posted on Thursday, September 9th, 2010 at 1:56 am and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

185 Responses to “How to calculate numbers of blocks from a building plan.”

  1. Nass Says:

    Thanks and God bless U sir.

  2. femi Says:

    Thanks.
    Good work.

  3. nuga Says:

    guy, u try God bless u

  4. Odika prince Says:

    Thanks man. U have made my I.T great for this that i have learned.

  5. Kayode Says:

    Thanks a lot for this fabulous information. God will continuing to enlarge your coast. thanks again.

  6. Shittu Olawale Says:

    Thanks so much u really help me

  7. Oluwa Says:

    This looks great.. Please i need advice from everyone on 4 bedroom bungalow.. any positive advice is welcome.. from Blocks, Cements, Rods, etc..

  8. Luap Says:

    Great Job, its amazing how many mason/bricklayer or QS will fumble through wrong calculations and give an overly high estimates of blocks for a single flat and result into over quantity and wastage. Its hard to understand why they cant learn from past quantity quotes or just follow a simple calculations like yours. Its amazing also that you will find out 85% of those who checked or posted a comment here are individuals house owners or prospective ones and not bricklayers/ building contractors themselves because its either most of them are not digital-information literate or are not willing to improve on their mistakes.

    I will share my mobile app for calculating quantity of all kinds of bricks and iron rods or cement for building per space soon, am working on it. check back all.

  9. John Says:

    Nice one. God bless you sir

  10. John Says:

    Please sir, as an upcoming engineer, how can estimate the total cost of a building project to a potential client and prepare my bill of quantity.

    I will be ever grateful if you can help me to solve this quotation challenge. Thanks

  11. bishop Says:

    really gud

  12. Am Oluwaseyi Says:

    I don’t know I can find someone who can explain dis.thank dat u are not a fish seller man; dis great. thanks Prof.

  13. igwe jaycee Says:

    plz do u have a text book or any material on this for sale. plz I will like to have it. my contact No. 08139627398 or email: cwavetech111@gmail.com… thanks a bunch for this wonderful knowledge sheared

  14. Tee-tee Says:

    Well done emma,I need ur mail n ur digit. Send 2 owoeye_taiwo@yahoo.co.uk thks

  15. cyril Says:

    bros you are wonderful God bless you. pls can i call you on phone for private talk?

  16. Engineer chinonso. Says:

    Honestly you did a great and wonderful work unknown to professionals of different field,for all those requesting for analysis onbreakdownof number of blocks to be used in their respective buildings, let me make this known to all sundry, building price and estimating analysis isn’t based on just mere assumptions, you must provide a good and reputable plans, because not all structures are builderable,you must provide a good plan so as to give insight to the quantity surveyor to analyse it for you,let me use this medium to correlate my works to all,i design good structures, be it bungalows, duplex, residential or commercial buildings.you can reach me 08030497621.imo state. That’s where i based.builders build right.

  17. Arc kingsley Says:

    Thank

  18. emma Says:

    yes . 08026228682

  19. emma Says:

    omionick@gmail.com 08026228682

  20. shola Says:

    I love dis explanation

  21. adalumo martins Says:

    It is interested and admireable job,i really thank you sir for your understanding towards this job. I am a freshed building technology student of federal polytecnic Ado, i have question to asked which goes, hwo can i get the easier way of calculating a 4bedroom boungallow?

  22. Paul Says:

    great job done. God bless you

  23. tope Says:

    Honestly, I must confess, this is d best building construction class ave ever attended. Keep it up, please

  24. ismail Says:

    Sir, you did a wonderful job here, I was worried and I google the required number of blocks, and I was taken straight to your site, you have lessen my burden and I now got the clearer picture and as a layman, I think I have learnt a lot from the responses as well, God will continue blessing you

  25. hammed mayowa Says:

    nice job. but this can be achieved with professionals such as builder,arch ,est survyor, civil engr. pls am using dis medium to be telling nigerians dat is better to engage experts dan rely on bricklayer alone bcos building is a life project. with moral aggrement and little fees u can achieve it. am builder hammed mayowa 08062451800. thank

  26. Giro Khan Says:

    Man, pls I’d like you to tell me an agreeable ammount a builder could charge a client in order for the client to have the satisfaction that he is not over paying and the builder himself is sure that he’s not cheated?
    Is there also a formula for calculating a builder’s own fee regardless the type/kind of building?

  27. OPEYLIBERTY Says:

    This I call a well done job! Thumb up…

  28. engr sheshi Says:

    I did the same research in 2010 and even take into consideration the morta space, and it gives me 98% accuracy…Good work keep it up

  29. ezichim Says:

    I.T. Defence made easy

  30. Femi Sholeye Says:

    Good Job and well done.

  31. arc hunkuyi Says:

    Nice work

  32. Don Bro Says:

    Very comprehensive and educative

  33. Akan Udoh Ezekiel Says:

    God bless u brother

  34. EMMANUEL Says:

    good calculation mr…..great job indeed so keep it up

  35. omomomi Says:

    I really love this…please I ll like it if I receive ur mails regularly

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