Dear colleagues,

Do you have any Building Problem? Post them to this forum and let the the experts on this forum answer them professionally.



Regards,
The Building Expert.

?
What type of roofing sheet is best for places very close to the sea?

Hello proptmart,

I suggest you use Cretetiles roof covering, because it is a sandcrete, ie a cement-sand based product and as such do not react to ocean salinity or other environmental degradations, also the all the tiles will have to be nail fixed because of the expected high ocean current. furthermore, the tiles each measuring 420mm by 365mm width is strapped compact in a pack of 5 pieces per pack, this makes handling and transportation easier. Presently, the Cretetiles averagely cost N3,600 per square metre including the cost of fixing the timber and tiles, this however excludes purchase of timber. I hope this info is useful to you.

Why Buildings collapse….

The spate of building collapse in Lagos has rattled the state government. This is coming at a time the nation is aspiring to become one of the top 20 economies in the world and when Lagos is racing in becoming a Mega city by 2020.
It was reported in punch newspaper dated 8th July 2007 that a TOTAL of 101 storey buildings have collapsed in Lagos State between 1978 and June 2007, and the same continued through the year 2008 where no fewer than five persons were feared dead and several others injured on 29th August, 2008, when a two-storey building collapsed in Asero area of Abeokuta, the Ogun State capital.
This brings to my attention as a responsible builder to explain to the public the reasons for such collapses. I must first emphasize the need for the use of qualified personnel in all construction activities as a way of restoring sanity in the industry.
Buildings, like all structures, are designed to support certain factored loads without deforming excessively. The loads are the weights of people, objects and the pressure of wind together called live loads and the dead load of the building itself.
The causes of building collapse can be classified under general headings to facilitate analysis. These headings are:
• Pre-construction stage:
1. Bad design calculations and detailing.
2. Lack of holistic interpretation of all site drawings as a total building package. i.e. M&E,HVAC,structural and Architectural drawings to be seen as one whole building package.
3. Lack of adequate soil investigation reports and proper interpretation of the same.
4. No record of laboratory results on building materials to be used /Quality Control & Quality Assurance.
5. Inadequate soil compaction and consolidation of reclaimed land causing differential settlement.
• During Construction stage:
1. Inexperienced site engineer / quacks.
2. Lack of proper supervision.
3. Use of substandard building materials. e.g Sandcrete blocks with improper cement /sand mix.
4. Improper constructional methods engaged. this is explained below:
a. sizes of aggregates, for instance must be related to the work under consideration, the following are guides:
• Foundation work – up to 25mm.
• Beam/Columns/Slab/Stairs – up to 20mm.
• Heavily reinforced work – up to 16mm.
The general rule is that size of the largest aggregates should be less that the space between the reinforcements. Failure to achieve this would result in honey combing and ultimately collapse, especially of building structures (beams, slab, stairs etc.).
b. Structural engineers should not specify concrete strength by volume. For example 1:2:4 mix; this has no meaning! Concrete characteristics strengths are the average of 28days strength and should be the yardstick of specifying concrete strength. As a rule, we have;
• Grade 20 – for building of not much structural importance such as bungalows, two storey buildings etc.
• Grade 25 – for general structure of importance and recommended for all concrete slabs including road culverts.
• Grade 30 – for more complex structures as bridges, earth retaining structures harbour walls, jetty, quarry walls, shoreline protect etc.
• Grade 40 – for prestressed concrete works and concrete works which requires great strength.
Concrete should be specified by concrete grades not by volume. As a guide the designer is strongly advised to design to concrete grade 20 and insist on 1:2:4 mix. On average, a good 1:2:4 mix will produce at least a grade 20 concrete.
c. Removing formwork before the concrete set time and supporting soffits of slabs/beam members with bamboo supports without calculating the required compressive strength vis-à-vis the number of bamboo supports needed for the flexural members. This information, if available, is very scarce to most bamboo users. It is important to note that in cases, where the props are going to support fresh loads up to 6m high, the props should be braced at the middle and the bottom of the props should not rest on bear grounds. They should be rested on platform that could transmit the load down effectively.
Excessive vibration of the concrete gang can also lead to the displacement of some of the props and in the process some may yield, leading to uneven load distribution or imminent collapse.
d. Improper curing of concrete. This weakens the compressive strength of the structural member, hence the load bearing capacity of the same bearing about different failure mode of the members.
5. Client involvement / greed by compromising quality with cost. This is mostly seen with private building owners, where due to his limited budget he constantly compromises quality of materials used. This would definitely reduce the characteristic strength of such material and hence its behaviour / response when periodically exposed to internal and external stresses. This of course would eventually lead to building collapse, if not immediately, some day.
6. Lack of Health Safety and Environment education. When the labour force that are engaged in the daily construction works are not properly orientated on professional ethics as it relates to constructional practices; discipline and respect for standards ,it would lead to bad workmanship or professional negligence as the case may be, which eventually leads to building collapse.

• Post Construction stage:
1. Occupants’ unpredictable habits e.g. breakdown structural members to cutout more rooms.
2. Additional loads. e.g. turning residential to commercial buildings.
3. Piling activities causing unnecessary vibrations to the nearby buildings.
4. Uncontrollable flooding would weaken the soil bearing capacity and result to settlement and hence foundation failure.
5. Roof leakage /failure or overspreading of the roof members.
6. Foundation failure.
7. Fire outbreak weakens the structural integrity of the members.
8. Natural disasters like hurricanes, earthquakes etc.
9. Lack of proper building maintenance and proper repair of distressed buildings.
10. Spalling of concrete due to exposure to salty atmosphere could weaken the structural strength of the members.
• Or a combination of the above stages.
• Failure modes.

Hello,
I have a friend here that has just one plot of land.
his question is what is the best way to utilise this plot. he intends to make a section of it for his residence and commercialise the other part. what can we advice him pls.

rgds

chainy

@ chainy,
i think it is best for your friend is to get a small structure at the back and some shops at the front if the location is commercial viable.

@ Aventure,

many thanx for your kind advice. however the location is not very commercial and shops would not be ideal there.

however, making a small structure behind is what he has to consider seriously.

rgds

chainy

Why Buildings collapse….


The spate of building collapse in Lagos has rattled the state government. This is coming at a time the nation is aspiring to become one of the top 20 economies in the world and when Lagos is racing in becoming a Mega city by 2020.
It was reported in punch newspaper dated 8th July 2007 that a TOTAL of 101 storey buildings have collapsed in Lagos State between 1978 and June 2007, and the same continued through the year 2008 where no fewer than five persons were feared dead and several others injured on 29th August, 2008, when a two-storey building collapsed in Asero area of Abeokuta, the Ogun State capital. 
This brings to my attention as a responsible builder to explain to the public the reasons for such collapses. I must first emphasize the need for the use of qualified personnel in all construction activities as a way of restoring sanity in the industry.
Buildings, like all structures, are designed to support certain factored loads without deforming excessively. The loads are the weights of people, objects and the pressure of wind together called live loads and the dead load of the building itself.
The causes of building collapse can be classified under general headings to facilitate analysis. These headings are:
• Pre-construction stage:
1. Bad design calculations and detailing.
2. Lack of holistic interpretation of all site drawings as a total building package. i.e. M&E,HVAC,structural and Architectural drawings to be seen as one whole building package.
3. Lack of adequate soil investigation reports and proper interpretation of the same.
4. No record of laboratory results on building materials to be used /Quality Control & Quality Assurance.
5. Inadequate soil compaction and consolidation of reclaimed land causing differential settlement.
• During Construction stage:
1. Inexperienced site engineer / quacks.
2. Lack of proper supervision.
3. Use of substandard building materials. e.g Sandcrete blocks with improper cement /sand mix.
4. Improper constructional methods engaged. this is explained below:
a. sizes of aggregates, for instance must be related to the work under consideration, the following are guides:
• Foundation work – up to 25mm.
• Beam/Columns/Slab/Stairs – up to 20mm.
• Heavily reinforced work – up to 16mm.
The general rule is that size of the largest aggregates should be less that the space between the reinforcements. Failure to achieve this would result in honey combing and ultimately collapse, especially of building structures (beams, slab, stairs etc.).
b. Structural engineers should not specify concrete strength by volume. For example 1:2:4 mix; this has no meaning! Concrete characteristics strengths are the average of 28days strength and should be the yardstick of specifying concrete strength. As a rule, we have;
• Grade 20 – for building of not much structural importance such as bungalows, two storey buildings etc.
• Grade 25 – for general structure of importance and recommended for all concrete slabs including road culverts.
• Grade 30 – for more complex structures as bridges, earth retaining structures harbour walls, jetty, quarry walls, shoreline protect etc.
• Grade 40 – for prestressed concrete works and concrete works which requires great strength.
Concrete should be specified by concrete grades not by volume. As a guide the designer is strongly advised to design to concrete grade 20 and insist on 1:2:4 mix. On average, a good 1:2:4 mix will produce at least a grade 20 concrete.
c. Removing formwork before the concrete set time and supporting soffits of slabs/beam members with bamboo supports without calculating the required compressive strength vis-à-vis the number of bamboo supports needed for the flexural members. This information, if available, is very scarce to most bamboo users. It is important to note that in cases, where the props are going to support fresh loads up to 6m high, the props should be braced at the middle and the bottom of the props should not rest on bear grounds. They should be rested on platform that could transmit the load down effectively.
Excessive vibration of the concrete gang can also lead to the displacement of some of the props and in the process some may yield, leading to uneven load distribution or imminent collapse.
d. Improper curing of concrete. This weakens the compressive strength of the structural member, hence the load bearing capacity of the same bearing about different failure mode of the members.
5. Client involvement / greed by compromising quality with cost. This is mostly seen with private building owners, where due to his limited budget he constantly compromises quality of materials used. This would definitely reduce the characteristic strength of such material and hence its behaviour / response when periodically exposed to internal and external stresses. This of course would eventually lead to building collapse, if not immediately, some day.
6. Lack of Health Safety and Environment education. When the labour force that are engaged in the daily construction works are  not properly orientated on professional ethics as it relates to constructional practices; discipline and respect for standards ,it would lead to bad workmanship or professional negligence as the case may be, which eventually leads to building collapse.

• Post Construction stage:
1. Occupants’ unpredictable habits e.g. breakdown structural members to cutout more rooms.
2. Additional loads. e.g. turning residential to commercial buildings.
3. Piling activities causing unnecessary vibrations to the nearby buildings.
4. Uncontrollable flooding would weaken the soil bearing capacity and result to settlement and hence foundation failure.
5. Roof leakage /failure or overspreading of the roof members.
6. Foundation failure.
7. Fire outbreak weakens the structural integrity of the members.
8. Natural disasters like hurricanes, earthquakes etc.
9. Lack of proper building maintenance and proper repair of distressed buildings.
10. Spalling of concrete due to exposure to salty atmosphere could weaken the structural strength of the members.
• Or a combination of the above stages.
• Failure modes.

@chainy,
i had a post on a unique duplex that can afforrd some1 of having room for other development, you can check the tread out it could be of help.

Am hoping to start my house next month,can you pls divide d house in 3 stages for me and wat it might cost. Its an american stlye duplex with 4bedroom and a pent house.

To get land and landed property at a cheaper rate within Good House between 2.5million upward, and Genuine Land within 100k per plot - Upward contact,
Accord Property Consult
Tel: 08036880283, 07083991081
website: accordconsult..com

Chainy:

Since u said the location is not a commercial zone, i am trying to imagine what particular area, nevertheless i would advice your friend to make a research on the prevailing rent within that location and the possibility of future development there like power, roads etc. if this are going to happen in the not too far future, then he should be thinking of the long term when designing his building.

Also if he has to commercialize part of his plot, the best location would in front of the building for security purpose except for rentals which can be located behind like Aventures explained.

If it is face-me-i-face-you building that is prevalent in the location, you can construct a self contained which is nicely built, well furnished and functional.I assure you it would be in high demand.

Another good question is how accessible is the place, drainage system, traffic, etc. this determines returns on investment. otherwise if the area would be opened in the future then you can think of how to utilize ur space more economical. Some even construct a fish pond behind and make huge money. This of cos must be backed with knowledge, patience, passion and constant monitoring. You can identify some joints, markets etc and be their supplier. Poultry is another line of business. Just think out of the box and take the step.

This is my Thumbs Rule: A good investment is when one can recoup his investment within minimum of 5yrs and a max of 10yrs otherwise it is not a good asset. e.g a location when rent is N250k per annum means 1.25million in 5yrs; This means you bought the land for that amount 5yrs ago. But buying for 7million and the land is 250k on rents; making returns after 5yrs to be 1.25million and 2.5million after 10yrs. Then its not a wise investment. This thumbs rule should guide us when buying landed properties and Buildings.




jjgirljay (f)
: The cost for the different stages should be within this range:

1. Foundation : 1,500,000 - 2,000,000 [/b]depend on the location and soil type (Foundation design).

[b]2. Superstructure : 1,500,000.

3. Roofing: [/b]btw 1,200,000 and 1,700,000.  Depending on the style and materials

[b]4. Supervision and Adminstration : 10% of the Total Building Cost. Although there is a new formular state in the Nigerian Institute of Building. I will post it later today. So just keep in touch.

The above a just for guidance and they are a function of designs, location, topography of the land, soil type, GeoTechnique Survey.etc


Hope this helps.


I hope this helps.

@mableswift, where is the location of this building? Have u taken time to ask d former occupant why did they leave soon? There are several reasons that cld cause this 1. Lack of value for the money, 2. location, 3. Physical evidence of lack of structural integrity 4 spiritual reasons.