The quality of materials used and the best practices with which are used to build structures determine how long the building will last before requiring structural upgrade.

Everything living and nonliving things have lifespans and expiry dates

opalu:


A bag of cement is 2 Headpans. So the mix ratio he used is 1:6:6.
I advise he uses at worst case 1:3:6 (1 bag, 6 sharp sand and 12 granite). This is the mix ratio for what Engrs like me call weak concrete. Maybe that brick layer say that you bought big sized granites only and he wants to tone it down by increasing the quantity of Sharp sand or maybe you don't have enough cement and they want to help you since they think "lintel is not carrying much weight ".
LINTEL IS AS IMPORTANT AS ANY STRUCTURAL ELEMENT! So I advise you use the same mix ratio you used for columns and slab for it. So instruct your bricklayer on what to do not vice versa since you pay d piper

God bless u for this sir, I really do appreciate. another question, should I stop my pillars at lintel level, since I'm not using parapet or head beam? Or I should extend it above the lintel to the building height? Thanks.

opalu:


A bag of cement is 2 Headpans. So the mix ratio he used is 1:6:6.
I advise he uses at worst case 1:3:6 (1 bag, 6 sharp sand and 12 granite). This is the mix ratio for what Engrs like me call weak concrete. Maybe that brick layer say that you bought big sized granites only and he wants to tone it down by increasing the quantity of Sharp sand or maybe you don't have enough cement and they want to help you since they think "lintel is not carrying much weight ".
LINTEL IS AS IMPORTANT AS ANY STRUCTURAL ELEMENT! So I advise you use the same mix ratio you used for columns and slab for it. So instruct your bricklayer on what to do not vice versa since you pay d piper

should I stop my pillars at lintel level, since I'm not using parapet or head beam? Or I should extend it above the lintel to the building height? Thanks.

johnson232:

should I stop my pillars at lintel level, since I'm not using parapet or head beam? Or I should extend it above the lintel to the building height? Thanks.

Okay. I didn't see this question.
Columns (pillars) are not to terminate at the lintel for any reason.
The concept is for the roof loading to be transferred unto the roof beams then all the pillars at that floor stop inside the roof beam to transmit the loads down.

But some people don't do roof beams to tie the whole of the pillars before they put roof wood carcass.
The roof beam is just like a lintel that is on top of the block wall before the roofing. The usefulness is that where you have the "parapet" it comes out of the roof beam. Where it's just roofing alone, the quater rods that bind the Wall plates for the Roof are embedded inside the reinforcement of the concrete roof beam.

So in general, it's best to take the pillars to the end of the block wall and also to cap it all with a concrete roof beam at least the external walls where the roof will sit on To be able to anchor the Wall plates properly against wind forces.

opalu:


Okay. I didn't see this question.
Columns (pillars) are not to terminate at the lintel for any reason.
The concept is for the roof loading to be transferred unto the roof beams then all the pillars at that floor stop inside the roof beam to transmit the loads down.

But some people don't do roof beams to tie the whole of the pillars before they put roof wood carcass.
The roof beam is just like a lintel that is on top of the block wall before the roofing. The usefulness is that where you have the "parapet" it comes out of the roof beam. Where it's just roofing alone, the quater rods that bind the Wall plates for the Roof are embedded inside the reinforcement of the concrete roof beam.

So in general, it's best to take the pillars to the end of the block wall and also to cap it all with a concrete roof beam at least the external walls where the roof will sit on To be able to anchor the Wall plates properly against wind forces.

God bless u sir... And my bricklayer was saying otherwise. Now I know it is always better to entrust one's project to professionals. Please what size of pillar do u suggest I use for my entrance porch? It is a 6inches block wall bungalow. My bricklayer is proposing 225mm x225mm Thanks.

johnson232:

God bless u sir... And my bricklayer was saying otherwise. Now I know it is always better to entrust one's project to professionals. Please what size of pillar do u suggest I use for my entrance porch? It is a 6inches block wall bungalow. My bricklayer is proposing 225mm x225mm Thanks.

The size of pillar for me trance porch 225x225 is adequate For simple 1 or 2 storey building. After the casting, at finishes stage, someone that designs mortar POP can do a mortar design round it for it to look thicker like round dia of 400mm or 500mm.

opalu:


The size of pillar for me trance porch 225x225 is adequate For simple 1 or 2 storey building. After the casting, at finishes stage, someone that designs mortar POP can do a mortar design round it for it to look thicker like round dia of 400mm or 500mm.

U're bless sir,I'm grateful... I have decided to settle for a mix ratio of 1:4:4 for all the concrete works, both for columns and lintels. Hope that is okay?

Do you mean 1 bag to 4 headpans each of sand and granite?

johnson232:

U're bless sir,I'm grateful... I have decided to settle for a mix ratio of 1:4:4 for all the concrete works, both for columns and lintels. Hope that is okay?

opalu:
Do you mean 1 bag to 4 headpans each of sand and granite?

Yes sir.

what would it cost to build a three bedroom flat on a dry land in ajah, all room ensuit

pls, how much did you use to process your governor consent, i need to process mine too

@opalu
Please what are the advantages or
disadvantages of using 6' block after the decking for a storey building.

Secondly, what will be ideal for pillars after the decking 16mm or 12mm

The structure is in a waterlogged area with pile foundation so we are thinking of measures to reduce dead weight as much as possible

johnson232:

Yes sir.

Ok. In that case 1 bag to 4 headpans of sharp sand to 4 headpans of granite Means 1:2:2 mix ratio.
THIS RATIO IS VERY ADEQUATE.
But you must know that is will be stronger than standard concrete Which is 1 bag to 4 headpans Sand and 8 headpans of well graded granite

opalu:


Ok. In that case 1 bag to 4 headpans of sharp sand to 4 headpans of granite Means 1:2:2 mix ratio.
THIS RATIO IS VERY ADEQUATE.
But you must know that is will be stronger than standard concrete Which is 1 bag to 4 headpans Sand and 8 headpans of well graded granite

Sorry I answered wrongly, I meant 1 bag of cement to 8 headpans of sand and 8 headpans of granite.

Cypost:
@opalu
Please what are the advantages or
disadvantages of using 6' block after the decking for a storey building.

Secondly, what will be ideal for pillars after the decking 16mm or 12mm

The structure is in a waterlogged area with pile foundation so we are thinking of measures to reduce dead weight as much as possible

The weight of the building must not necessarily be lighter. There are instances whereby the structure must be made heavy in order for stability to occur. There are other instances whereby weight must be reduced not to overload the foundation. That is why a competent structural engineer is required for any structural issues. Just as you need a medical professional for medical issues.

Now to your question on 6 inches block, gorgeous simple storey building, you could use them for partition walls where you won't require a 9 inches column (225x225mm) or else the columns will shoot out and that is ugly. But it is advisable to use 9 inches blocks for the external walls at the upper 1st floor to reduce weight on the suspended slab (decking).

On the reinforcement in columns for upper floor, the minimum reinforcement is 4Y16 Even for the highest floor. However in the real estate sector majority of builders use 4Y12 for upper floors simply because to them those columns are only carry Roof load.
But I hate that practice because 1st the cost difference is always negligible (except it's a gigantic project). Secondly there are instances that in future undue extra loads could be placed up and 4Y12 in columns will not work.

Real life experience: Early this year, a foreigner gave someone money to build a house for him in Lekki. The man used 4Y12 at all the columns on the upper floor. He even omitted some because to him nothing was up above it. Surprisingly a decision was made to add pent floor. They did that without structural advice.
when massive cracks started, I was called to solve it.

johnson232:

Sorry I answered wrongly, I meant 1 bag of cement to 8 headpans of sand and 8 headpans of granite.

8 headpans for sharpsand is too much. Reduce it to 4 if the granite is well graded meaning it has different sizes of granite in the trip. If it's only big sized granites you could get, then increase the sharp sand to 5 or 6.

Reason being that when the size of granite are the big, there is tendency for voids to be created between them. Hence those spaces weaken the concrete even if sand fills the voids. when there are different sizes (I don't mean shapes) of granite, theN during casting and vibra-tion, ththe smaller sizes will find their ways into the voids between the bigger ones

opalu:


8 headpans for sharpsand is too much. Reduce it to 4 if the granite is well graded meaning it has different sizes of granite in the trip. If it's only big sized granites you could get, then increase the sharp sand to 5 or 6.

Reason being that when the size of granite are the big, there is tendency for voids to be created between them. Hence those spaces weaken the concrete even if sand fills the voids. when there are different sizes (I don't mean shapes) of granite, theN during casting and vibra-tion, ththe smaller sizes will find their ways into the voids between the bigger ones

Thanks a lot sir. If that is the case, isn't it more better to cast concrete with the smallest size of granite(chippings)?

johnson232:

Thanks a lot sir. If that is the case, isn't it more better to cast concrete with the smallest size of granite(chippings)?

No. Different sizes of granite is the best. on many occasions I have experimented and have proved that well graded is the strongest and the best for concrete.
How did I do this? I took small sized granite for sample 1, then took big sized granite for sample 2 and took different sizes for sample 3. Then cast the three concrete mixes separately using the same cement and sand. Three different set of standard cubes were made. After 21 days and 28 days, these cubes were taken to be crushed in a concrete laboratory. The results showed that the well-graded Sample was the strongest because it took longest before it crushed.

opalu:


No. Different sizes of granite is the best. on many occasions I have experimented and have proved that well graded is the strongest and the best for concrete.
How did I do this? I took small sized granite for sample 1, then took big sized granite for sample 2 and took different sizes for sample 3. Then cast the three concrete mixes separately using the same cement and sand. Three different set of standard cubes were made. After 21 days and 28 days, these cubes were taken to be crushed in a concrete laboratory. The results showed that the well-graded Sample was the strongest because it took longest before it crushed.

You are good...

opalu:


The weight of the building must not necessarily be lighter. There are instances whereby the structure must be made heavy in order for stability to occur. There are other instances whereby weight must be reduced not to overload the foundation. That is why a competent structural engineer is required for any structural issues. Just as you need a medical professional for medical issues.

Now to your question on 6 inches block, gorgeous simple storey building, you could use them for partition walls where you won't require a 9 inches column (225x225mm) or else the columns will shoot out and that is ugly. But it is advisable to use 9 inches blocks for the external walls at the upper 1st floor to reduce weight on the suspended slab (decking).

On the reinforcement in columns for upper floor, the minimum reinforcement is 4Y16 Even for the highest floor. However in the real estate sector majority of builders use 4Y12 for upper floors simply because to them those columns are only carry Roof load.
But I hate that practice because 1st the cost difference is always negligible (except it's a gigantic project). Secondly there are instances that in future undue extra loads could be placed up and 4Y12 in columns will not work.

Real life experience: Early this year, a foreigner gave someone money to build a house for him in Lekki. The man used 4Y12 at all the columns on the upper floor. He even omitted some because to him nothing was up above it. Surprisingly a decision was made to add pent floor. They did that without structural advice.
when massive cracks started, I was called to solve it.

Thanks for your explanation. I appreciate
Happy sunday

opalu:


No. Different sizes of granite is the best. on many occasions I have experimented and have proved that well graded is the strongest and the best for concrete.

Happy sunday to u sir. Pls which do recommend between elephant and dangotee cement. Which is more suitable for concrete and block moulding?

johnson232:

You are good...

Thanks bro. Na God win.

johnson232:

Happy sunday to u sir. Pls which do recommend between elephant and dangotee cement. Which is more suitable for concrete and block moulding?

Thanks Sir.
There has been a war between the two. And since it took a political dimension I decided not to put myself to support anybody the two but to use both for my projects.

Let me explain. We Dangote used political influence to import greatest portion of cement into the country yeats back, Dangote Cement was good. When the Dangote Obajana Cement was opened in Kogi to service Abuja and other northern states, we discovered that 'Dangote Lagos' that was imported was far better than 'Dangote Abjua'. I was heading the construction of 30 Luxury mansions in Wuye Abuja at the time and we tested dangote and Elephant (Lafarge).
To our surprise Danote failed in all. So we used Elephant in all that project.
So in order to correct the anomalies which I think they noticed from different feedbacks, the Dangote company upgraded their cement everywhere to a quick-setting-time Cement that is slightly better than Elephant product. This cost them real money.
They then decided to use SON to force other cement companies to upgrade to it.
Check this link:
http://www.punchng.com/special-feature/dangote-lafarge-battle-for-cement-market-dominance/

So I use Dangote 42.5 grade and also use Elephant of any grade.

opalu:


Thanks Sir.
There has been a war between the two. And since it took a political dimension I decided not to put myself to support anybody the two but to use both for my projects.

Let me explain. We Dangote used political influence to import greatest portion of cement into the country yeats back, Dangote Cement was good. When the Dangote Obajana Cement was opened in Kogi to service Abuja and other northern states, we discovered that 'Dangote Lagos' that was imported was far better than 'Dangote Abjua'. I was heading the construction of 30 Luxury mansions in Wuye Abuja at the time and we tested dangote and Elephant (Lafarge).
To our surprise Danote failed in all. So we used Elephant in all that project.
So in order to correct the anomalies which I think they noticed from different feedbacks, the Dangote company upgraded their cement everywhere to a quick-setting-time Cement that is slightly better than Elephant product. This cost them real money.
They then decided to use SON to force other cement companies to upgrade to it.
Check this link:
http://www.punchng.com/special-feature/dangote-lafarge-battle-for-cement-market-dominance/

So I use Dangote 42.5 grade and also use Elephant of any grade.

I know dangote cement have different grade with different strength. But does it mean all elephant cement grade are the same? Don't they vary in terms of strength sir?

johnson232:

I know dangote cement have different grade with different strength. But does it mean all elephant cement grade are the same? Don't they vary in terms of strength sir?

Elephant cement also have the one they call 'Superset'.
However the Mix ratio is what we should really be focused on (provided it
Is not the 32.5 Dangote Cement ).
For several decades grade of Cement has never been an issue until some persons brought that in.

opalu:


Elephant cement also have the one they call 'Superset'.
However the Mix ratio is what we should really be focused on (provided it
Is not the 32.5 Dangote Cement ).
For several decades grade of Cement has never been an issue until some persons brought that in.

Thanks for the explanations, I really do appreciate sir. But with this your wealth of knowledge, I hope it won't cost someone a fortune to hire u?

johnson232:

Thanks for the explanations, I really do appreciate sir. But with this your wealth of knowledge, I hope it won't cost someone a fortune to hire u?

A trial will convince you.

Good day Opalu,

I need to do a soil test to determine the type of foundation required for a 1 story building (four 3-bedroom flats) on a swampy land. Below are the 2 options that I have from two different soil test engineers.

1 borehole test and four 2.5 ton CPT. This costs less and the engineer is saying that I do not need a 10 ton CPT since he is doing a borehole test.
1 borehole test and four 10 ton CPT. This costs more cause of the 10 ton CPT.

Based on your professional experience, which of the the two would you advise I go for. Am tempted to go for the cheaper one.

childcare:
Good day Opalu,
I need to do a soil test to determine the type of foundation required for a 1 story building (four 3-bedroom flats) on a swampy land. Below are the 2 options that I have from two different soil test engineers.
1 borehole test and four 2.5 ton CPT. This costs less and the engineer is saying that I do not need a 10 ton CPT since he is doing a borehole test.
1 borehole test and four 10 ton CPT. This costs more cause of the 10 ton CPT.
Based on your professional experience, which of the the two would you advise I go for. Am tempted to go for the cheaper one.

Borehole test is called Standard Penetration Test (SPT). It investigates deep down into the soil up to 30 metres (like the height of 10 storey buildings inside the ground). The borehole test is good for very bad soils esp those requiring piles. The test also helps the owner of the land to confirm that his building will or will not require pile foundation etc.
on the other hand, the one you call CPT is Dutch Cone Penetrometre Test (DCPT). It is faster and cheaper. It goes to like 3 m depth and more or less.

Your answer : with a borehole and 2.5ton CPT, you don't need 10ton CPT. But you can do it to satisfy your conscience. But i speak as someone who do or interprete these tests daily for clients. Thanks

opalu:


Borehole test is called Standard Penetration Test (SPT). It investigates deep down into the soil up to 30 metres (like the height of 10 storey buildings inside the ground). The borehole test is good for very bad soils esp those requiring piles. The test also helps the owner of the land to confirm that his building will or will not require pile foundation etc.
on the other hand, the one you call CPT is Dutch Cone Penetrometre Test (DCPT). It is faster and cheaper. It goes to like 3 m depth and more or less.

Your answer : with a borehole and 2.5ton CPT, you don't need 10ton CPT. But you can do it to satisfy your conscience. But i speak as someone who do or interprete these tests daily for clients. Thanks

Thanks a lot for your explanations, I will stick with the borehole and 2.5ton CPT , my conscience too they cut cost , lol

childcare:

Thanks a lot for your explanations, I will stick with the borehole and 2.5ton CPT , my conscience too they cut cost , lol

You are welcome

Cypost:

Thanks for your explanation. I appreciate
Happy sunday

Thanks alot