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Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! - Properties - Nairaland

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Landlords Grow Rich In Their Sleep. You Can As Well. Invest In These Lands Today / We Have These Lands For Sales And Inspection / ALL THESE LANDS ARE AVAILABLE FOR ANYTHING YOU WANT TO DO WITH IT-DON'T MISS IT (2) (3) (4)

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Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 7:58pm On Feb 24, 2016
[b]Greetings Nairalanders.

I had started this topic on my main thread ( https://www.nairaland.com/2836058/talk-quantity-surveyors-construction-costs ) sometime ago but I felt I should create a dedicated thread for it in order for Nairalanders to view and adequately comment on this topic.

I have decided to bring up this topic due to the various experiences that have been encountered over the years about how some unsuitable lands have unexpectedly resulted in enormous increase in construction costs for various people (individual and corporate), and even led to the point of abandonment or delayed completion of their projects.

Land may not be seen by many as part of basic construction costs, but its one of the major resources required for any construction project to take place. For those building for private use and more importantly, investment purposes, the kind of land they purchase would in the long run affect their overall investment in such projects because land, in so many ways, affect overall construction costs.

It has become increasingly important for prospective buyers of land to not hurriedly pay money for lands because they are cheap, but to ensure they do some due diligence to determine how economical it would be to build on such land. A lot of times, prospective buyers are only interested in the legal aspects of the land and not necessarily the physical characteristics of the land.

Some people have said that if they see a plot of land which looks good on the surface, taking out time to carry out this due diligence might make them lose the land to another buyer, but let me say here that “it is better to be sure about a thing than to be sorry about it later.”

In a bid to forestall this recurring event for prospective building owners and as a seasoned construction cost professional, I have decided to discuss this topic while expecting contributions from Nairalanders who have had similar experiences, such that we can all learn and make wiser investment decisions in future. I will give some real life examples/experiences where I can in order to drive home the point.
I will categorize these lands in terms of location, physical nature, topography, etc.

I shall be making more posts soonest on this topic.

YOU ARE WELCOME!![/b]
[/b]

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 8:05pm On Feb 24, 2016
BEWARE!! – BUYING THESE LANDS MAY INCREASE YOUR CONSTRUCTION COST ASTRONOMICALLY! (PART 2)

WATERLOGGED LAND

This is a kind of land that has a high water table. A common way of identifying such land is observing the surface of the land just after a downpour of rain. If the rainwater remains on the surface many hours or even days after the downpour, then surely that land is waterlogged. Also, a muddy/marshy surface is also a tell-tale sign of water-logged land. This is the reason why some people have said that the rainy season is always the best time to source for and purchase land, as it shows the land in its actual physical state.

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 8:11pm On Feb 24, 2016
[b]WATERLOGGED LAND - THE ISSUES – The pertinent issues that may arise when using waterlogged land for construction and which directly affect construction costs are:

 Increased quantity of filling – In order to make a waterlogged land buildable/usable, it would have to be filled with filling materials (laterite, hardcore, rubbles), compacted and left to consolidate. This activity could be costly depending on the size (length x breadth) of the land and the overall thickness of the filling, determined by the structural engineer.

 Soil stabilization processes – This involves mixing the soil with certain materials required to stabilize the soil where it has been discovered through soil tests that the soil is unstable due to its waterlogged nature and/or presence of unstable materials in the soil. I remember that soil stabilization using cement and sharp sand was done on a branch project for one of the prominent banks at Amuwo Odofin, Lagos sometime between 2010 and 2011 due to the nature of the soil. It should be noted that this soil stabilization process for this project was estimated to cost approximately N11, 000,000 out of about N24,000,000 which was estimated for the foundation works for that branch project.[/b]

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 8:44pm On Feb 24, 2016
[b]WATERLOGGED LAND - THE ISSUES (CONTINUED)

 Introduction of retaining walls – Where the land level is raised by a large quantity of filling, there will always be a need to construct concrete retaining walls on all sides of the land, so as to retain the filling. This is especially necessary where the new level of the land after filling is higher than the adjoining lands/properties; and the perimeter fence of the plot would be constructed on these retaining walls. It is common knowledge that constructing retaining walls, be it concrete or gravity walls, are expensive. For example, a reinforced concrete retaining wall of dimensions; 300mm thick x 1.00 metre high with a footing/toe beam of 600mm wide would cost about N27,000 per metre. If you take a standard plot of 18 x 36 metres, the perimeter[ (2 x (L+B)] is 108 metres x N25,000 = N2 700,000!! Compare this cost with that of building a complete bungalow, and you would see how waterlogged land can astronomically increase your construction costs.

 The use of complex and more expensive foundations like raft foundations, pile foundations – Waterlogged lands would almost always require more expensive foundations, other than the usual strip and/or combined strip and ; anything short of using more expensive foundations as advised by the engineer, would lead to structural defects in the short or long run. A former neighbour of mine who moved to another rented apartment somewhere around Berger, Lagos told me his story of how he bought a plot of land in that area with the aim of building a bungalow on it; however, after his engineer visited the land to carry out soil tests, it was discovered that the only feasible foundation that could be constructed on the land was a pile foundation which was estimated to cost about N5,000,000, though the man only intended to build a bungalow on the land!![/b]

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by jayp01: 9:29pm On Feb 24, 2016
Very educative piece. Kudos.
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 9:29pm On Feb 24, 2016
WATERLOGGED LAND - THE ISSUES (CONTINUED)

 Continuous pumping of ground water throughout the foundation works – Due to the high water table of waterlogged lands, constructing foundations on them require constant pumping of ground water from the excavations and sometimes, draining of the land using pipes buried underground. Considering the cost of hiring pumps per day, this could be a major cost for the client depending on the number of days or weeks the foundation works would last for.

In conclusion, it is important for a prospective land buyer to employ the services of an engineer to carry out a soil test on the land in order to ascertain the soil characteristics and hence, make informed decisions on the land purchase and also the foundation design.

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 9:40pm On Feb 24, 2016
jayp01:
Very educative piece. Kudos.

Thanks for the compliments.

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 10:30pm On Feb 24, 2016
Your comments, contributions and/or questions on this topic are welcome.
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by Nobody: 4:49am On Feb 25, 2016
olumide4christ:
Your comments, contributions and/or questions on this topic are welcome.

I wanted a hilltop land on a slope for views. I got it.

I wanted a specific architectural plan. I got it.

The plan and the lot don't agree without much expense.

340 tons later at a cost of N300,000 and counting I am still filling. This doesn't take account the cost of the extra height foundation and the extra support.

Moral of story, be sure on your land and design a proper plan that will utilize the uniqueness of it.

Nice thread.

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by ifyalways(f): 6:13am On Feb 25, 2016
Why type in all bold @ OP?

brb

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by brabus(m): 7:11am On Feb 25, 2016
You can build on any land provided you carry out preliminary site investigation.

1. A physical site investigation is a must before you make any land purchase.

2. Architects and builders must visit the site prior to design and estimation for any project.

I carried out soil investigation test for a client in 2011 (in Ogombo area) and the report turn out the client will require pile foundation to support the load coming on it. That's the end of the story, the client ended up not buying the land and that's wisdom. The client (a Nairalander) said he's fine parting with 500k to conduct a test than spending all his life fortune building a house. Till date the land is still undeveloped.

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 4:42pm On Feb 25, 2016
@ Brabus; @EgunMogaji, thanks a lot for your comments and contributions.

The main purpose of the thread is to make people aware of the need for due diligence before they purchase their land so that in the words pf the man Brabus quoted....they don't spend their life's fortune in building a house.

@EgunMogaji....Funny enough, I have a personal experience similar to yours where my site was on a bit of a slopy terrain and we had to do quite a lot of filling and higher foundation walls. I'll share some of those issues later on this thread.

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 5:02pm On Feb 25, 2016
[color=#006600]BEWARE!! – BUYING THESE LANDS MAY INCREASE YOUR CONSTRUCTION COST ASTRONOMICALLY! (PART 3)

[color=#000000]LAND BELOW THE LEVEL OF THE MAIN ROAD AND PUBLIC DRAIN

This is a kind of land in which the average level of the land lies below the level of the main or access road to the site. In other words, when accessing the subject land/plot from the road, its like you are on a higher level on the road and as such, are driving downwards from the road into the plot, rather than upwards/upland. Sometimes, there may currently not be an established road adjoining the plot but every prospective land owner needs to make some findings in order to determine if the government has earmarked a road to be constructed there. If so, it would be advisable for the client not to buy into such land, for if he/she does, the government road and public drain, when constructed, may most likely have a higher level than the compound.

LAND BELOW THE LEVEL OF THE MAIN ROAD AND PUBLIC DRAIN - THE ISSUES – Why is buying land below the level of the main road and public drain (existing or proposed) an issue which can astronomically increase your construction costs? I will explain.

 Incessant flooding – Water as we know will always find its level i.e. water will always naturally flow from highland to lowland. If a building is built on a land that is naturally lower than the road, when rain falls, water will flow from the road into the compound due to the difference in level and also, rain water in the compound will have nowhere to flow to, thus, causing incessant flooding whenever rain falls and also rendering the soil in the compound wet on a regular basis because water table would also rise. If the land has already been bought, any experienced engineer, quantity surveyor, architect who is to supervise the project will advise the client to fill the entire plot with imported filling sand in order to raise the compound level above the road level and then leave for a while to consolidate in order to forestall flooding. Some might also suggest making the foundation of the building higher, perhaps 1.8 -2.0 metres high, but this will only prevent the building from flooding, and not the compound, thus its not an all-round solution.

The cost of filling an entire plot with filling sand could be astronomical depending on the size of the plot and the thickness of the filling. For example, to fill to make levels a standard plot of 18 x 36 metres of 1 metre thickness, we would require = 18.00 x 36.00 x 1.00 = 648m3 of filling sand.
Using some conversion factors, 648m3 of sand comes to about 56 lorryloads of 20 tonnes.
56 lorryloads @ N20,000/trip = N1,120,000. Note that this is an example and could be more or less depending on the size of land and height of filling.
If you compare the cost of filling above to the cost of putting up a 3-bedroom bungalow (which ranges from N6, 000,000 – N12, 000,000, depending on size and finishes) on such land, you can see that buying such land has increased construction costs. When you add the cost of retaining walls to retain this filling as discussed earlier in this topic, the enormous additional cost is glaring for all to see. I heard some years back that this problem affected a lot of properties in Badore, Ajah after the government constructed the main road in the area, but I know that such problem is not limited to such area. Infact, the church where I worship had this issue for years; measures are being taken now to correct the problem.[/color][/color]

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by mavverick: 5:10pm On Feb 25, 2016
I have some questions.

Who carries out a soil test ? Civil engineer or a geologist ? In Nigeria, most people claim to be everything. Do you have a trusted soil engineer or geologist that you can recommend ?

From your write-up, does this mean that virtually almost everywhere in Lekki there is no running away from either raft/pile ?

In which cases can you have a mixture of raft + blocks to reduce cost without compromising on structural integrity ?
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 5:36pm On Feb 25, 2016
mavverick:
I have some questions.

Who carries out a soil test ? Civil engineer or a geologist ? In Nigeria, most people claim to be everything. Do you have a trusted soil engineer or geologist that you can recommend ?

From your write-up, does this mean that virtually almost everywhere in Lekki there is no running away from either raft/pile ?

In which cases can you have a mixture of raft + blocks to reduce cost without compromising on structural integrity ?

[b]Answer to Q1 - In Nigeria, soil test can be carried out by both civil (structural) engineers & geologists. Note that not all civil engineers are structural engineers, its an area of specialization. However, in projects I have worked on, structural engineers have carried out the soil tests and gotten the actual results. In some projects, some prime consultants (architects) on a project mandate that the structural engineer who would prepare the structural drawings for the project should not be the same person who should carry out the soil test i.e. they advise the client on the need to invite another engineer or geologist, aside the structural engineer on the project to carry out the soil test. It has to do with some form of professional ethics, won't indulge into that here.
If you need someone to carry out a soil test, I have a trusted structural engineer who I can refer to you.

Answer to Q2 - I'm afraid that such is the case...Lekki is majorly sand-filled (reclaimed) ground and as such cheaper foundations like strip or strip-and-pad foundations can't be structurally stable on such ground. If I can remember, there was a thread in this section where a bungalow was to be built on raft foundation because of the soil conditions...imagine that!!

Answer to Q3 - Building with raft and blocks in foundation SHOULD AND ONLY SHOULD be done based on the instruction of the engineer who designed the foundation. Raft is supposed to be a monolithic foundation but if the engineer based on his calculations ascertains that blocks can be used to make up the top of the raft foundation, then its his call and if any issues come up in future, he would be held liable for that decision. So therefore, let the structural engineer consent to that before you mix raft foundation with blocks. [/b]

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by brabus(m): 5:52pm On Feb 25, 2016
Soil test/investigation also called Geotechnical Survey is carried out by Soil Scientist. Interestingly, it is not enough to have anyone carry out soil investigation, the most important thing is to have the result confirmed in the Labs.

And they carry out so many types of tests ranging from CPT (Cone penetration Test) to SPT (Standard penetration test). Triaxial testing, Bearing Capacity Test, Borehole drilling and Geophysical survey, Pile integrity test and Pile construction, Pile load test and more.

The most common type of test carried out in Ajah area is CPT. Most building engineers rely on given datas for areas they're working on than carrying out the test.

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 9:15pm On Feb 25, 2016
[b]LAND BELOW THE LEVEL OF THE MAIN ROAD AND PUBLIC DRAIN - THE ISSUES (CONTINUED)

 Non-drainage of compound – There is always a need for every building to be able to drain away rainwater from roofs and compound pavings and waste water from wash hand basins, bathrooms and sinks through small drains in the compound into the public drain outside of the compound. This will only be achievable if the invert levels (lowest point of a drain) of the compound drain is higher than the invert level of the public drain. If otherwise, the waste and rain water from the compound will not be able to drain into the public drain. Resolving this issue is technical and capital-intensive, requiring construction of a sump and regular pumping of the effluents into the public drain and this will continue through the life of the building. Another option would be to construct a soakaway to drain all the waste and rain water but with time, depending on the level of the water table, the soil will become water-logged with its attendant problems. Another option would be to channel the waste and rain water into adjacent lands that are yet to be developed, but aside from this being a form of trespass into other lands, it will only be a stop-gap measure as when the adjacent lands are developed, there would be no outlet to channel the effluents.

In conclusion, it is essential to take out time to do some land investigation and make some critical enquiries prior to purchasing lands for construction.[/b]

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 9:34pm On Feb 25, 2016
Your comments, contributions and/or questions on this topic are welcome.
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by smiley001(m): 10:12pm On Feb 25, 2016
Nice thread.
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 1:56am On Feb 26, 2016
smiley001:
Nice thread.

Thanks Smiley001.
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by mavverick: 11:02am On Feb 26, 2016
Thanks for answering my questions.

Is it such that in the Lekki terrain, its just better to see a land during the raining season so that one can see the natural state of the land as the dry season can give a wrong illusion.

For a layman, apart from when there is an existing drainage to guage whether you are stepping down into a plot or stepping up into a plot, how can you tell instantly if a plot is on a highland etc or tell if its going to take a lot of filling etc.


olumide4christ:


[b]Answer to Q1 - In Nigeria, soil test can be carried out by both civil (structural) engineers & geologists. Note that not all civil engineers are structural engineers, its an area of specialization. However, in projects I have worked on, structural engineers have carried out the soil tests and gotten the actual results. In some projects, some prime consultants (architects) on a project mandate that the structural engineer who would prepare the structural drawings for the project should not be the same person who should carry out the soil test i.e. they advise the client on the need to invite another engineer or geologist, aside the structural engineer on the project to carry out the soil test. It has to do with some form of professional ethics, won't indulge into that here.
If you need someone to carry out a soil test, I have a trusted structural engineer who I can refer to you.

Answer to Q2 - I'm afraid that such is the case...Lekki is majorly sand-filled (reclaimed) ground and as such cheaper foundations like strip or strip-and-pad foundations can't be structurally stable on such ground. If I can remember, there was a thread in this section where a bungalow was to be built on raft foundation because of the soil conditions...imagine that!!

Answer to Q3 - Building with raft and blocks in foundation SHOULD AND ONLY SHOULD be done based on the instruction of the engineer who designed the foundation. Raft is supposed to be a monolithic foundation but if the engineer based on his calculations ascertains that blocks can be used to make up the top of the raft foundation, then its his call and if any issues come up in future, he would be held liable for that decision. So therefore, let the structural engineer consent to that before you mix raft foundation with blocks. [/b]
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by mavverick: 11:04am On Feb 26, 2016
Thanks for answering.
Is CPT good enough though or is it safer to go further, and are the results of a soil test easy to digest for a non builder.

Is the practice of assuming, if 90% of people on my street are doing raft, then raft should be good for me as well a safe one ?


brabus:
Soil test/investigation also called Geotechnical Survey is carried out by Soil Scientist. Interestingly, it is not enough to have anyone carry out soil investigation, the most important thing is to have the result confirmed in the Labs.

And they carry out so many types of tests ranging from CPT (Cone penetration Test) to SPT (Standard penetration test). Triaxial testing, Bearing Capacity Test, Borehole drilling and Geophysical survey, Pile integrity test and Pile construction, Pile load test and more.

The most common type of test carried out in Ajah area is CPT. Most building engineers rely on given datas for areas they're working on than carrying out the test.
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 4:35pm On Feb 26, 2016
mavverick:
Thanks for answering my questions.

Is it such that in the Lekki terrain, its just better to see a land during the raining season so that one can see the natural state of the land as the dry season can give a wrong illusion.

For a layman, apart from when there is an existing drainage to guage whether you are stepping down into a plot or stepping up into a plot, how can you tell instantly if a plot is on a highland etc or tell if its going to take a lot of filling etc.



[b]Well, to answer your 1st question, I'll say that that option is the best - to inspect land during the rainy season rather than dry season, not just in Lekki, but in all lowland areas.

For the 2nd question, I'll say that any experienced construction professional should know quite a lot about topography and terrain should be able to visit any site and from observation, determine a land that would require a lot of filling or otherwise; whether the land is on highland or lowland, etc. All these & some other issues (such as identifying natural or man-made obstructions existent or running across the site, etc) to take note of are what is academically called site investigation. Its different from soil investigation which involves determining the soil strata & bearing capacity of the soil which requires scientific methods/tests to be carried out, some of which Brabus has enumerated previously.

This is the reason why its advised that aside from bringing in an architect to a land to take measurements, its necessary to bring in a Quantity Surveyor into such site to do some site investigation/observations with a cost point of view. He/she will identify issues on the land that might increase the construction costs ab initio, even without preparing a BOQ. Architects are not trained to always see things from a cost point of view. Happily, more clients are beginning to realise this and as such, bring in Quantity Surveyors into their projects, as the prime consultant, so as to leverage on their cost expertise to save costs. [/b]

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 5:18pm On Feb 26, 2016
[b]BEWARE!! – BUYING THESE LANDS MAY INCREASE YOUR CONSTRUCTION COST ASTRONOMICALLY! (PART 4)


SLOPING LAND

This is a kind of land that has a steep gradient (or slopes) from one end of it to the other and/or in different directions, usually encountered in hilly terrain.

The Issues – The pertinent issues that may arise when using sloping land for construction are:

 Limitation of design – Due to the sloping nature of the land, architects are usually limited to design buildings with different levels leading to stepped foundations, in a bid to reduce cost.

 High foundations – As a result of the sloping nature of the land, foundations would have to be made higher either by structural design or by implementation on site. This results in - increasing the height of the foundation blockwall or concrete raft ground beams; increased quantity of filling sand resulting from the increased height of foundation; introduction of concrete tie beams (in case of blockwall foundations) due to the increased height of blockwork.

In conclusion, if possible, it is advisable to avoid buying sloping land; it leads to increased cost of foundation works. I have a personal experience on this, when I bought a sloping land in an estate in Abuja some years ago. Due to the sloping nature of the land, we eventually ended up spending about N2.1 million for foundation works for the main building and boys quarters, as against about N1.6 – 1.7 million due to the factors mentioned above.[/b]
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by brabus(m): 4:41pm On Feb 27, 2016
Sloping Land can be a mixed blessing. I mean it's a good and bad land. Good when you make best use of the slope to build a basement. Bad when you are on the receiving end of a very steep slope. You'll have to deal with unending flood and damp when not properly tackled.

The best way to tackle slopes is to get a caterpillar to do cut and fill for you. You won't spend more than 150k to achieve that. And this can be achieved in less than 6 hours.
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by brabus(m): 5:02pm On Feb 27, 2016
mavverick:
Thanks for answering.
Is CPT good enough though or is it safer to go further, and are the results of a soil test easy to digest for a non builder.

Is the practice of assuming, if 90% of people on my street are doing raft, then raft should be good for me as well a safe one ?



The results of the test are pretty easy to digest.

Here's a sample of test carried out at Ogombo. The proposed development is 6 unit of 3 bedroom on 3 floors.

Samples collected at various depth

1. Sandy Soil (0.0m)
2. Dark Brownish fine sand (0.75m)
3. Ditto (1.5m)
4. Grey fine sand (2.25m)
5 - 7. Ditto (4.5m)
8. Brown sharp sand (5.25m)
9 - 11 Ditto (7.5m)
12. Grey fine sand (8.25m)
13 - 15 Ditto (10.5m)
16. Yellow fine sand (11.25m)
17 - 19 Ditto (13.5m)
20. Dark Grey Silty Sandy Clay (14.25m)
21 - 23 Ditto (16.5m)
24. Dark Grey Stiff Clay Sandy (17.25m)
25 - 31 Ditto (22.5m)

Ranking of soil for foundations: (from best to unsuitable):

Sand & Gravel - Best
Medium & Hard Clays - Good
Silts & Soft Clays - Poor
Organic Silt and Clays - Undesirable
Peat - Unsuitable

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by brabus(m): 5:20pm On Feb 27, 2016
mavverick:

Is the practice of assuming, if 90% of people on my street are doing raft, then raft should be good for me as well a safe one ?

I'll suggest you read further the summary of the test carried out. Even the bearings capacity of various subsoil differs in the soil report and so one cannot adopt a one size fits all when developing in areas with weaker soil.

Summary of the report and recommendations of the soil test

Objectives
1. To determine the relevant geotechnical/engineering parameters of the soil strata.
2. To evaluate the findings to determine the suitability of the site for the proposed development
3. To evaluate the results for recommendation on the most appropriate and economic type of foundation design and construction/fdn depth.
4. To evaluate the allowable soil bearing pressure that could be adopted for the design of the recommended foundation.
5. To determine the appropriate precautions and methods to be adopted in the excavation and construction of the fdn/boundary wall/drainage system.

The Results and Recommendation

The test revealed 7 major subsoil zones but the 2nd and 3rd subsoil zones which extends to 8.25m depth is considered suitable for the proposed structure due to the low compressibility nature of the soil and as such excessive settlement is not envisaged.

This mean some subsoil zones were unsuitable even though the test is carried out on the same hole.

Good news you think! Read on!

The test result recommended a maximum ground loading of about 50.0KN/m2 which is expected to exerted per plan area at foundation level. Technical detail (ask your structural engineer what that means).
The test result also went further to recommend that construction should commence during the dry season.

Recommended foundation type: only to be determined based on the recommended working loads in the report. So, your foundation type should be designed based on the technical data received from the soil test report. It shouldn't be based on assumption.

Lastly, the allowable bearing capacity is taken as 70kN/m2 which is relatively safe to support low to moderate superstructure loads.

However, when the client took the data to his structural engineer, the recommended foundation was Pile and the depth is over 10m

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 8:54pm On Feb 27, 2016
brabus:
Sloping Land can be a mixed blessing. I mean it's a good and bad land. Good when you make best use of the slope to build a basement. Bad when you are on the receiving end of a very steep slope. You'll have to deal with unending flood and damp when not properly tackled.

The best way to tackle slopes is to get a caterpillar to do cut and fill for you. You won't spend more than 150k to achieve that. And this can be achieved in less than 6 hours.

True...though take note of the bolded above....even after doing cut and fill, you may still need to construct a retaining wall any which way, which involves quite some additional cost. Also, constructing a basement is not beans or ogi & akara in terms of money ooo!! Don't think any person trying to cut costs by using direct labour, cutting corners in terms of standards, etc which we see people doing here everyday will be able to afford doing a basement.

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Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 4:40pm On Feb 29, 2016
[b]BEWARE!! – BUYING THESE LANDS MAY INCREASE YOUR CONSTRUCTION COST ASTRONOMICALLY! (PART 5)

LAND BESIDE WATER BODIES (STREAMS, RIVERS)

This is a kind of land which borders rivers, streams or which has rivers, streams or other water bodies running through them. Where a land is close to such water bodies, prospective land buyers should verify the extents of the land they intend to purchase so as to ensure that the land area does not comprise of such water bodies.

THE ISSUES – The major issues that may arise when constructing on such lands include:

 Filling to make up levels – The water bodies would have to be filled up and left to consolidate before construction work can commence. Such filling could be massive depending on the depth of such water bodies. I know of an existing situation in Abuja where a plot of land with an area of (20 x 30 metres =600m2), close to a stream was paid for some years ago and some months after, when setting out was to be done, it was discovered that the front part of the plot of land extended into the stream by about 7 metres, meaning that the front area of the plot which was meant for car park would need to be filled (or reclaimed) and a retaining wall constructed in order to retain the filling. This would amount to additional costs from N500,000- N1,000,000 which was never budgeted for.

 Retaining wall construction – As explained in the example above, retaining wall would need to be constructed in order to protect the land from the erosive action of the river/stream.[/b]
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 8:49pm On Feb 29, 2016
LAND BESIDE WATER BODIES (STREAMS, RIVERS) - THE ISSUES (CONTINUED)

 Re-channelization of river/stream – This would need to be done if the river/stream passes through the land, and not at the border or edge of it. This would involve the use of heavy machinery, of which the costs would grossly affect the budget outlay of the client. Also, if the new channel of the river/stream had to pass through some farmlands, the client would have to pay compensation to the owners of the farmland. I remember this happened on a particular project comprising construction of semi-detached duplexes in which I was involved in Abuja around Apo, Dutse District in 2011/2012. The client, a real estate mortgage bank, where I was working then, had to incur extra costs due to re-channelization and compensation costs because a stream flowed through the site.
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by olumide4christ: 8:00pm On Mar 02, 2016
[b]BEWARE!! – BUYING THESE LANDS MAY INCREASE YOUR CONSTRUCTION COST ASTRONOMICALLY! (CONCLUDING PART)

LAND AT THE END OF A SLOPING ROAD

This is a type of land situated at the end of a sloping road. The land itself may be in a good natural condition, but the main issue here is that during the rainy season, flood waters from higher up the road would naturally flow downwards to the lowest point of the road where this land is situated and gather and collect and if the road has no proper public drainage that effectively takes effluents away, the resultant floodwaters would find its way into the compound if the land is at a lower level than the road. Usually, the solutions to this problem are palliative measures such as construction of retaining walls to prevent ingress of floodwaters into the compound OR if the consultant supervising the project is proactive, he/she would suggest that the level of the site is raised by sand filling to a point such that the floodwaters would flow elsewhere to points of lower levels and not into the compound.

In summary, if a client would purchase such land, he/she should ensure that the public drainage around the site is functioning and not blocked; if the drainage is functioning effectively, there may not be any cause for alarm unless the public drain becomes blocked in the future.[/b]
Re: Beware! – Buying These Lands May Increase Your Construction Cost Astronomically! by Nobody: 9:21pm On Mar 02, 2016
nice.

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