opalu:


Call it joke but I have sworn to expose whatever is wrong as far as construction is concerned. If you have pictures of all these anomalies you highlighted, then expose such highly risky behaviours of artisans so that others can learn. Let us not sound as if bitter about something else.
Using a ladder to go up and down the house is condemnable in all ramifications. If I know this guy or this location, I will send one of my carpenters to do a very solid wooden staircase like "mallam step" for him free of charge since I have woods. So him and his wife or babe could go up and down.
But my man, don't defend the indefensible

It's not a joke and I call things the way I see them. Sorry if that ruffled your feathers or if it appears to you that I'm bitter.

It's amazing who you world savers are not on major builders threads to warn them of all sorts of infractions that we see daily on here.

I don't defend indefensible but I defend those that are not here to defend themselves and will always do that.

Edit: You know what on second thoughts, e-argue is not why I'm here. I'm here to learn from educators and stop share my little knowledge with others. You guys win, but remember that karma is a female canine.

Seun, where is the ignore user filter we've been asking for?

QUESTION FROM A NAIRALANDER:
"I bought a parcel of land that has already built raft foundation for 3 storey building. On inquiry I learnt that it was done about 15 years ago. This year I want to build my 1 storey building on it since it tallies with my Architectural design. Is it advisable to use the old foundation or I should demolish it and start afresh?"


PLEASE CONTRIBUTE MY FELLOW PROFESSIONALS

opalu:
QUESTION FROM A NAIRALANDER:
"I bought a parcel of land that has already built raft foundation for 3 storey building. On inquiry I learnt that it was done about 15 years ago. This year I want to build my 1 storey building on it since it tallies with my Architectural design. Is it advisable to use the old foundation or I should demolish it and start afresh?"


PLEASE CONTRIBUTE MY FELLOW PROFESSIONALS

One can build a new house on top of an existing foundation, the real question is should one build on an old foundation? 15yrs is quite a long time, more than a decade. what is the current state of the existing foundation. Are there visible signs of undermining; cracks, is it broken, is it crumbling, These are important questions that you might require an engineer’s report to tell.

Since the size, shape and layout of the existing foundation conform to what the client want to build, it maybe ok if the foundation is still in a good state. But building on an existing foundation could limit you and waste potential wonderful views or cause you to lose privacy.

Personally I'll advise a new one, because u wouldn't know the spacing & type of rebars that is in the existing one, though considering building on existing foundation maybe due to financial constraint, it's always better to start building from foundation, except structures were detailed documentation is available, should incase any issue comes up....

opalu:
QUESTION FROM A NAIRALANDER:
"I bought a parcel of land that has already built raft foundation for 3 storey building. On inquiry I learnt that it was done about 15 years ago. This year I want to build my 1 storey building on it since it tallies with my Architectural design. Is it advisable to use the old foundation or I should demolish it and start afresh?"


PLEASE CONTRIBUTE MY FELLOW PROFESSIONALS

This one is strong.

Seriously you should consider getting a site visit by a professional. No sure what of what vocation though, maybe a structural engineer?

Was your offer based on the existing foundation or you just found it as a bonus? If as a bonus then I personally would tear it up and do my own.

Thanks for the two responses. You guys are on point

opalu:
Thanks for the two responses. You guys are on point

If you do tear it up then you'll have yourself a mountain of free fill dirt for the new foundation

Hello Boss.

I have some questions for you Opalu.

Which is better structurally, pre-cast parapet or freshly casted ?
When casting septic tanks, any precautions to take ? Mine is being casted on the surface and then buried into the ground.
The front of my plot doesn't have drainage, however at the rear there is drainage, how easy is it to have some kind of slope on the compound so that surface water can drain towards the rear.
What are your thoughts on underground drainage pipework, I don't have much space on the side setbacks, so thinking of routing all drainage pipes underground, albeit with a slope or gradient to facilitate easy drainage.

Thanks.

opalu:
Example of building done without the right Professionals.

@Opalu... that is a wonderful/door implementation... what a professional LOL!!

Hajji M.

mufutau55:


@Opalu... that is a wonderful/door implementation... what a professional LOL!!

Hajji M.

Thanks Hajji M

babaeko1:
Hello Boss.

I have some questions for you Opalu.

Which is better structurally, pre-cast parapet or freshly casted ?
When casting septic tanks, any precautions to take ? Mine is being casted on the surface and then buried into the ground.
The front of my plot doesn't have drainage, however at the rear there is drainage, how easy is it to have some kind of slope on the compound so that surface water can drain towards the rear.
What are your thoughts on underground drainage pipework, I don't have much space on the side setbacks, so thinking of routing all drainage pipes underground, albeit with a slope or gradient to facilitate easy drainage.

Thanks.

1. Both precast or in situ casting are okay. What determines your choice should be which of them is more suitable for your kind of work And which is very economical for you. For instance I use precast Lintels and 'freshly cast' lintels depending on which one helps me achieve my milestone in the project management. One is not stronger than the other. It is the mix ratio and proper casting that determines the strength.
.2. When casting Soakaway, few precautions is that a. Make sure your iron bender arrange the Rebars in such a way that the horizontal and vertical (main and distribution ) bars make a square. That means the spacing for primary bars must be the same with the runners. B. Use very strong concrete mix atleast 1:2:4. C. Use original water proof cement not fake ones You buy under bridge for obalende. D. If you cast it on ground before sinking, use felting around it if you can. E. Pay a professional to help you check the casting or before casting because I can't say all here.
.3. About drainage being at the back you can either fill the entire compound with filling sand to slope every surface runoff to the back or just run some tiny drains along the fence that have gradient to take any water that enters them to the major drainage at the back. If you can use underground drainage, better. Just make sure the diameter or dimensions of the underground drain is big enough to avoid blockage. Or just place inspection chambers at interval for maintenence

Hello Opalu.
I bought a sandy plot of land with no standing water three years ago at Ibeju Lekki. I just, infact, received my governor's consent last week.
I want to build a story building with three bedroom on each floor. (Three bedroom on ground floor another three bedroom on upper floor).
Can you please give me an idea of how much a raft foundation will cost me?

openbook:
Hello Opalu.
I bought a sandy plot of land with no standing water three years ago at Ibeju Lekki. I just, infact, received my governor's consent last week.
I want to build a story building with three bedroom on each floor. (Three bedroom on ground floor another three bedroom on upper floor).
Can you please give me an idea of how much a raft foundation will cost me?

Do you have a building plan? If yes send in PDF to ab2day@gmail.com so I could give you an exact quote. If you don't have call me on 08039353737.

Opalu

How you dey.

I have a question for you, who is better placed to cast a paraphet, a Bricklayer or caster ? Any advantages/disadvantages to using either of them ?

Also if one does blockwork and paraphet, any risk with leaving it for a few months before roofing ?
With a fence which has 2 coash of raft work, any risk with leaving the fence without coping for some time ? I mean any problems with not doing coping yet and rains etc ?

Thanks.

babaeko1:
Opalu

How you dey.

I have a question for you, who is better placed to cast a paraphet, a Bricklayer or caster ? Any advantages/disadvantages to using either of them ?

Also if one does blockwork and paraphet, any risk with leaving it for a few months before roofing ?
With a fence which has 2 coash of raft work, any risk with leaving the fence without coping for some time ? I mean any problems with not doing coping yet and rains etc ?

Thanks.

Excellent questions.

Dear opalu.
Should I be worried if my builder is using 12headpans of sand & 12 headpans of granite to one bag of cement to cast my lintels? The number of wheelbarrows to one bag he was using on site seems to many to me. He's a bricklayer though.

@Opalu,
Please can I have your email address?

opalu:


Thanks sir

@Opalu1,
Please can share some names of these water proof cement so I can make sure I am aware of these when doing any soakaway work on my site?

Opalu1:



1. Both precast or in situ casting are okay. What determines your choice should be which of them is more suitable for your kind of work And which is very economical for you. For instance I use precast Lintels and 'freshly cast' lintels depending on which one helps me achieve my milestone in the project management. One is not stronger than the other. It is the mix ratio and proper casting that determines the strength.
.2. When casting Soakaway, few precautions is that a. Make sure your iron bender arrange the Rebars in such a way that the horizontal and vertical (main and distribution ) bars make a square. That means the spacing for primary bars must be the same with the runners. B. Use very strong concrete mix atleast 1:2:4. C. Use original water proof cement not fake ones You buy under bridge for obalende. D. If you cast it on ground before sinking, use felting around it if you can. E. Pay a professional to help you check the casting or before casting because I can't say all here.
.3. About drainage being at the back you can either fill the entire compound with filling sand to slope every surface runoff to the back or just run some tiny drains along the fence that have gradient to take any water that enters them to the major drainage at the back. If you can use underground drainage, better. Just make sure the diameter or dimensions of the underground drain is big enough to avoid blockage. Or just place inspection chambers at interval for maintenence

My personal email address is ab2day@gmail.com.
Thanks

johnson232:
Dear opalu.
Should I be worried if my builder is using 12headpans of sand & 12 headpans of granite to one bag of cement to cast my lintels? The number of wheelbarrows to one bag he was using on site seems to many to me. He's a bricklayer though.

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

opalu:
There is a vital aspect of using inadequate foundation. The determination of the type of foundation a building requires is done by the Structural designs matched with the Soil Investigation/tests. The Structural Engineer through his Analysis estimates the entire loads that is coming on the foundation at various points. Where the foundation required is raft, he determines the depth that will be both SAFE and COST EFFECTIVE. But in a conflict between safety and Cost, the safety takes precedence or else the architect is called in to redesign the building to make it smaller/lighter.
Last year, I did an entire structural designs for an estate at Elegushi in lekki. And the Owner insisted I reduce the raft to 750mm depth. But based on my designs, 750 depth will fail. So I didn't. By the time they the foundations were done to my standard, as soon as the ground floor slabs were completed, heavy rain fell and the ground floor of many estates around the site were submerged, all the ground floor of all his own estate were not flooded.
That was when he knew I did a good job for him.
Apart from flooding, the ability of the foundation to carry the dead and imposed loads for at least 100 years is what is critical.

Good day sir.

please I need practical answers as applicable on site; from experience.
what's the maximum length for beams of 450mm height when designing(structural design) a residential apartment

thank you.

adonismuller:
not really, beams are required in spans of 4.5m and above

so 4m by 4m room; they won't be a need another beam running in the middle to support the suspended slab?

UnimkeAk:


so 4m by 4m room; they won't be a need another beam running in the middle to support the suspended slab?

its optional...so long ur slab is richly reinforced,then its ok.

adonismuller:
its optional...so long ur slab is richly reinforced,then its ok.

y12B @175mm going both ways?

UnimkeAk:


y12B @175mm going both ways?

its okay though,125 spacing is preferable since there will be no beam

adonismuller:
its okay though,125 spacing is preferable since there will be no beam

i'll do 150mm

thank you

@Opalu1,
Please can share some names of these water proof cement so I can make sure I am aware of these when doing any soakaway work on my site?
Is this an additive that is mixed with normal cement or is this a type of cement? I have asked around and people don't and my cement suppliers don't seem to know this.
Also how is this used? Is this used with the cement during the casting of the soakaway or is it used as a plaster layer after casting the soakaway?

What sizes do they come in and do you know roughly how much they cost?

Await your response.

opalu:
My personal email address is ab2day@gmail.com.
Thanks

opalu:


If it is a Ground floor slab of a simple building, it has to be Monolithic. Meaning the floor has to act as a single entity.
But if the span is becoming too large to the point that it will react to Extreme weather conditions, then expansion/construction joints have to be introduced as shown in picture above.
It is the same principle used in Filling station slabs as well as Bridge decks

correct use on large span floors.

Keep the questions coming

UnimkeAk:

Good day sir.
please I need practical answers as applicable on site; from experience.
what's the maximum length for beams of 450mm height when designing(structural design) a residential apartment
thank you.

In Structural designs the maximum length for beam 450mm or any beam at all depends on the type of loading pattern it is subjected to.
If it is a primary (main) beam, it is subjected to higher loads. But if it is secondary beam it could be Longer.

Apart from the loading, other factors affect how long the 450 mm beam can be include the Concrete mix, casting method, yield strength of Reinforcement etc.
so allow your structural engineer to determine that. Or let me see your drawing

Happy new week

babaeko1:
Opalu

How you dey.

I have a question for you, who is better placed to cast a paraphet, a Bricklayer or caster ? Any advantages/disadvantages to using either of them ?

Also if one does blockwork and paraphet, any risk with leaving it for a few months before roofing ?
With a fence which has 2 coash of raft work, any risk with leaving the fence without coping for some time ? I mean any problems with not doing coping yet and rains etc ?

Thanks.

A Bricklayer/Mason is the best person to cast anything After the carpenter has done the formwork.
Even when you give casting to a caster he must engage a bricklayer/Mason to be at the point that the labourers are pouring the wet concrete if not it will be rubbish wOrk

happy sallah to you all.