House near Rattanaburi, surin

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Re: House near Rattanaburi, surin

Postby tertim » Fri May 27, 2016 2:16 pm

pipoz wrote:Hi Pipoz
I will be using the 605 80mm thick planks which will support a safe live load of 300KG without additional concrete topping, of course a screed will be laid on top for tiling but this is considered non structural and is indeed part of the live load calculations.
Just received quote from company in Roi et for B45,000 delivered on site, I have decided to install the slabs myself making a considerable saving on the B25,000 already quoted.

So my new estimate is 45,000+2,000(labour)= 47,000/120M2 about B400 per M2 which is considerably less than the other two methods od constructing a 1st floor concrete slab.

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Hi tertim and that's good

The topping screed with a wire mesh will add to your safe live load capacity (if you need it - which I doubt you will for a residential use) according to that Table from the Supplier

What span are you going for with the 605 80mm thick plank?

Is that new quote from the Company in Roi Et http://www.rc-con.co.th/

I am contemplating using your Hollow Core idea for my Flat Roof Slab area to my Garage

pipoz .[/quote]

Hi pipoz

The 605 80mm x 0.6M wide plank is 4.15M long to span 4M which gives a safe live load of 304KG/M2 without additional concrete topping.


Yes the company from Roi et ,if you can communicate in Thai with them you will probably get a better response, I sent email in English but after 4 days my wife sent email in Thai and had the quote within hours.

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Re: House near Rattanaburi, surin

Postby tertim » Fri May 27, 2016 2:53 pm

Roger Ramjet wrote:
tertim wrote:I will be using the 605 80mm thick planks which will support a safe live load of 300KG without additional concrete topping, of course a screed will be laid on top for tiling but this is considered non structural and is indeed part of the live load calculations.

I hate to be the bearer of bad news but pre-stressed slabs need to be tied together, which is why trench mesh and concrete are lade over the top after a liberal cover of binding material like Lanko so that both lot of concrete mesh together.
Think about your 300 kg load, it's not much when you consider a man weighing say 75 kilos jumps from a ladder onto the slab. Then the forces applied to the planks is increased 10 fold, depending on the height he jumps from and his weight because he lands on just his feet. It's the same as watching a lady in high heels try and walk on a tarred road or footpath during a very hot day, the force is far in excess of the opposite force.
It's why in most cases where pre-stressed slabs are used the manufacturer will recommend a top screed layer with trench mesh incorporated.
Here's just one of a hundred sites that talk about why you should: http://www.cscscreeding.co.uk/2011/09/c ... te-planks/
It's a British site and refers to screeding, which is why I posted it.


Hi RR had a look at the web site you suggested very informative packed with information and good advice. They certainly bring up some problems with the HC slabs being warped, concave or convex and also out of alignment and level. I think most of the problems arise with the beams (which the HC planks sit on) not being level or straight and this is down to poor building practice and attention to detail. The HC companies stress the importance of level straight beams for the planks to sit on and give a figure of +/ - 10mm in the level plane, I think this is a rather generous tolerance and will be aiming for + / - 5mm

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Re: House near Rattanaburi, surin

Postby pipoz » Fri May 27, 2016 3:21 pm

Hi pipoz

The 605 80mm x 0.6M wide plank is 4.15M long to span 4M which gives a safe live load of 304KG/M2 without additional concrete topping.


Yes the company from Roi et ,if you can communicate in Thai with them you will probably get a better response, I sent email in English but after 4 days my wife sent email in Thai and had the quote within hours.

Pop kan mai[/quote]

Thanks tertim, good news

I will probably look at a 5m or 6m span, so may have to go up to 100 mm thick

I have a Thai Architect at work, so I will get him to email the Company for a Price to Supply, Deliver to and Off Load (only) at Udon Thani,

Its about 275kms from the Roi Et Airport to my place in Udon Thani

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Re: House near Rattanaburi, surin

Postby Roger Ramjet » Fri May 27, 2016 4:38 pm

tertim wrote:The HC companies stress the importance of level straight beams for the planks to sit on and give a figure of +/ - 10mm in the level plane, I think this is a rather generous tolerance and will be aiming for + / - 5mm

This is Thailand, never forget that and just to give you some idea about tolerances. I have a TV cabinet that sits on four 3" diameter legs and wondered what the PSI would be when loaded with TV, stereo, video, satellite translator etc etc. It's made from solid wood and quite heavy on it's own. Not being too bright at the time I had a mate lift it with me at one end and we placed it on my wife's bathroom scales.........which I might add the dial went around the clock a number of times before the whole thing crapped itself, so you are looking at constant pressure from say a kitchen table with marble or granite top in the region of tons and also the TV stand.
The slabs (planks) are pre-stressed, they do this by stretching wire/rebar then pouring the concrete around the wires and when it sets they cut the wire/rebar which pulls the whole things together. If they get the timing wrong and the concrete has not set properly in some places it will warp the slab/plank and should be discarded, but again this is Thailand, so they skim it, which makes it look perfect, but is in actual fact defect. Now think of the kitchen table leg sitting on this one defective area. Well, I'm sure you get the idea.
And now people are talking about cutting them to fit, which makes them totally un-pre-stressed. Cut one of those wires/rebar and the whole thing is just concrete on its own, which might be strong, but breaks easily. When I did both my floors and garage roof each slab/plank was ordered to size so they remained stressed and I still used Lanko and poured 4 inches of concrete over the trench mesh I placed on top.... just to be on the safe side.
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Re: House near Rattanaburi, surin

Postby tertim » Sat May 28, 2016 7:39 am

Roger Ramjet wrote:
tertim wrote:The HC companies stress the importance of level straight beams for the planks to sit on and give a figure of +/ - 10mm in the level plane, I think this is a rather generous tolerance and will be aiming for + / - 5mm

This is Thailand, never forget that and just to give you some idea about tolerances. I have a TV cabinet that sits on four 3" diameter legs and wondered what the PSI would be when loaded with TV, stereo, video, satellite translator etc etc. It's made from solid wood and quite heavy on it's own. Not being too bright at the time I had a mate lift it with me at one end and we placed it on my wife's bathroom scales.........which I might add the dial went around the clock a number of times before the whole thing crapped itself, so you are looking at constant pressure from say a kitchen table with marble or granite top in the region of tons and also the TV stand.
The slabs (planks) are pre-stressed, they do this by stretching wire/rebar then pouring the concrete around the wires and when it sets they cut the wire/rebar which pulls the whole things together. If they get the timing wrong and the concrete has not set properly in some places it will warp the slab/plank and should be discarded, but again this is Thailand, so they skim it, which makes it look perfect, but is in actual fact defect. Now think of the kitchen table leg sitting on this one defective area. Well, I'm sure you get the idea.
And now people are talking about cutting them to fit, which makes them totally un-pre-stressed. Cut one of those wires/rebar and the whole thing is just concrete on its own, which might be strong, but breaks easily. When I did both my floors and garage roof each slab/plank was ordered to size so they remained stressed and I still used Lanko and poured 4 inches of concrete over the trench mesh I placed on top.... just to be on the safe side.


I am using the UK building regs as a basis for my floor loading, these regs have built up over the last 100 years using calculation, material testing, experience(good and bad) working practice etc. I am quite happy to use these figures for my calculations but of course if you feel you need an additional safety factor for your own building then that is your choice but don't forget when you increase the safety factor you will add additional weight to the structure but I can see from your own build photo's that you have considered that.
columns and beams on stilts 1 e.jpg
HC slab at column

I agree with you that cutting the HC slabs in the middle or close to the middle and cutting through the wire would be detrimental but as you can see from the image the slabs are only cut in the corners and even if the wires were cut here it would have no effect on the performance of the slab.

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Re: House near Rattanaburi, surin

Postby Roger Ramjet » Sat May 28, 2016 8:00 am

tertim wrote:I am using the UK building regs as a basis for my floor loading, these regs have built up over the last 100 years using calculation, material testing, experience(good and bad) working practice etc. I am quite happy to use these figures for my calculations

Which is why I mentioned This is Thailand and also posted the UK site that tells you about the problems even in the UK.
I'm not trying to change your mind about how you do it, I know many people who have used the hollow core slabs, I'm just telling you of the problems you may encounter that haven't been factored in your plans and I'd hate to hear after that there were problems.
I just watched a indoor badminton court (20 courts) being built near where I live using the hollow core slabs, but they poured concrete as well.
Your photo is not of the hollow core pre-stressed slabs but of the other type, which have only four (sometimes three) steel cores to them and not along the strongest part of the slab, which in your case is the outside.
Anyway, good luck with the build and if you do find any that are suspect, send them back. We found 7 in ours and they were replaced immediately.
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Re: House near Rattanaburi, surin

Postby tertim » Sat May 28, 2016 9:53 am

Roger Ramjet wrote:
tertim wrote:I am using the UK building regs as a basis for my floor loading, these regs have built up over the last 100 years using calculation, material testing, experience(good and bad) working practice etc. I am quite happy to use these figures for my calculations

Which is why I mentioned This is Thailand and also posted the UK site that tells you about the problems even in the UK.
I'm not trying to change your mind about how you do it, I know many people who have used the hollow core slabs, I'm just telling you of the problems you may encounter that haven't been factored in your plans and I'd hate to hear after that there were problems.
I just watched a indoor badminton court (20 courts) being built near where I live using the hollow core slabs, but they poured concrete as well.
Your photo is not of the hollow core pre-stressed slabs but of the other type, which have only four (sometimes three) steel cores to them and not along the strongest part of the slab, which in your case is the outside.
Anyway, good luck with the build and if you do find any that are suspect, send them back. We found 7 in ours and they were replaced immediately.


Hi RR
Thank you RR I much appreciate your comments and value your opinions even though sometimes I may not agree with them, by having these exchanges it can help us and other forum members to make decisions about their own build. It has certainly made me think about quality control issues when using components made by others in which I have no control over. When I return to Isaan(next week) I will visit the plant in Roi et to make my own judgment as to their ability to produce a good product.

Yes you are correct the photo of the HC slabs was just a random pic from the web and not the HC slabs I will be using, I will try and find a pic of the actual HC slabs I will using.

Thank you for your good wishes we all need a little bit of luck now and then.

PS Just to let you know in the coming months i will be constructing the 1st floor beams using a technique which I am sure will draw a lot of comments!!

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Re: House near Rattanaburi, surin

Postby pipoz » Sat May 28, 2016 11:53 am

[/quote]

Hi Pipoz
I will be using the 605 80mm thick planks which will support a safe live load of 300KG without additional concrete topping, of course a screed will be laid on top for tiling but this is considered non structural and is indeed part of the live load calculations.
Just received quote from company in Roi et for B45,000 delivered on site, I have decided to install the slabs myself making a considerable saving on the B25,000 already quoted.

So my new estimate is 45,000+2,000(labour)= 47,000/120M2 about B400 per M2 which is considerably less than the other two methods of constructing a 1st floor concrete slab.

Pop kan mai[/quote]

Hi tertim,

Just, I just received my quote from them for 100 m2 of HC (0.10x0.60x6.0m), supply & deliver to site (Udon Thani)
Material & Delivery TB 45,000
VAT 7% TB 3,150

Total TB 48,150, which equates to TB 481 per m2, a bit more than yours due to extra Transport distance and length of planks

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Re: House near Rattanaburi, surin

Postby tertim » Sat May 28, 2016 3:11 pm

pipoz wrote:



Hi tertim,

Just, I just received my quote from them for 100 m2 of HC (0.10x0.60x6.0m), supply & deliver to site (Udon Thani)
Material & Delivery TB 45,000
VAT 7% TB 3,150

Total TB 48,150, which equates to TB 481 per m2, a bit more than yours due to extra Transport distance and length of planks

pipoz[/quote]

Hi pipoz

Wow that seems to be a very keen price when you consider that you have specified the 100mm HC slabs and the delivery distance more than three times my distance from factory. I must admit that RR has got me thinking about quality control issues and if there is very little price difference may consider stepping up to 100mm HC slabs also .

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Re: Raised House near Rattanaburi, surin

Postby tertim » Sun Jun 05, 2016 7:32 pm

So now we are back in Isaan to resume our build, traveled for 24 hours phuket to Rattanaburi with a short stop in Bangkok for shower and rest.The move went very smooth he arrived on time and delivered on time I highly recommended his service. It took 6 hours to load the truck and 20 minutes to unload ( about 20 people helped and would only accept a couple of bottles of lao khao)

Started off a little gently checking the site to see how the drains are working, they look to be doing a good job of redirecting the rain water into the adjacent pond also making a work bench.
Two days later and we have started on the ground beams, making good progress whilst keeping and eye on the weather.

We are getting a quote from a local builder for labour only to complete our house, we will complete the ground floor slab and columns then he will carry on and complete the build apart from the electrics, plumbing and painting, hoping for a keen price as he has just finished a double story house and is looking for work.
IMG_20160604_071151.jpg
Work bench
IMG_20160605_162000.jpg
Blinding prior to fixing the beams
IMG_20160605_161945.jpg


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Re: House near Rattanaburi, surin

Postby Roger Ramjet » Sun Jun 05, 2016 9:22 pm

tertim,
Don't let them pour concrete onto the ground, it weakens it by over 30% as all the water drains straight into the surrounding soil. You can buy a roll of thick black plastic (100 metres X 2 metres) for about 1,000 baht and that stops the water from going into the soil. Concrete is a chemical mixture and water is the most important part that needs to stay in the mixture for at least a week to a month.
You should also cover the poured concrete with wet hessian so the water doesn't evaporate too quickly.
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Re: House near Rattanaburi, surin

Postby tertim » Sun Jun 05, 2016 9:51 pm

Roger Ramjet wrote:tertim,
Don't let them pour concrete onto the ground, it weakens it by over 30% as all the water drains straight into the surrounding soil. You can buy a roll of thick black plastic (100 metres X 2 metres) for about 1,000 baht and that stops the water from going into the soil. Concrete is a chemical mixture and water is the most important part that needs to stay in the mixture for at least a week to a month.
You should also cover the poured concrete with wet hessian so the water doesn't evaporate too quickly.

Hi RR the pics I've posted only show the blinding concrete, this is to provide a clean environment for fixing the beam steel and shuttering the structural concrete is then poured.
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Re: House near Rattanaburi, surin

Postby Roger Ramjet » Mon Jun 06, 2016 12:43 am

tertim wrote:Hi RR the pics I've posted only show the blinding concrete, this is to provide a clean environment for fixing the beam steel and shuttering the structural concrete is then poured.

I know, but now you are going to pour tons of concrete on top of the weaken concrete and expect the columns from the footings to carry all the weight for the first week. I'm not having a shot at you, I'm just pointing out facts. It's a good way to have beams that are sagging in the middle and have no structural strength. At least normally the ground is sand and has been compacted if you are going the way you are. And there's a long way between the footings columns and the where the beam links.
You're letting your builder do it his way because of laziness.
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Re: House near Rattanaburi, surin

Postby tertim » Mon Jun 06, 2016 6:36 am

Roger Ramjet wrote:
tertim wrote:Hi RR the pics I've posted only show the blinding concrete, this is to provide a clean environment for fixing the beam steel and shuttering the structural concrete is then poured.

I know, but now you are going to pour tons of concrete on top of the weaken concrete and expect the columns from the footings to carry all the weight for the first week. I'm not having a shot at you, I'm just pointing out facts. It's a good way to have beams that are sagging in the middle and have no structural strength. At least normally the ground is sand and has been compacted if you are going the way you are. And there's a long way between the footings columns and the where the beam links.
You're letting your builder do it his way because of laziness.


You say you know but I wonder if you really do understand.
The method of construction I am using is considered good practice in civil engineering RC works, in which I have many years experience.
As I stated before the blinding concrete is there to provide a clean environment for placing the rebar and has the additional benefit of preventing the water leaching out of the uncured concrete.
The maximum weight the ground will have to support for my largest beam(4M) of uncured concrete is 1000KG which works out at 1250KG/M2 , A person walking on the ground will produce a far greater force probably by a factor of ten.
So yes I am very confident the ground will support the uncured concrete for 7 days and its not LAZINESS but good building practice.

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Re: House near Rattanaburi, surin

Postby Roger Ramjet » Mon Jun 06, 2016 10:10 am

tertim wrote:The method of construction I am using is considered good practice in civil engineering RC works, in which I have many years experience.

The method you are using also uses compacted sand under the concrete and in many cases black plastic as a barrier in reinforced concrete works.
I'll wait until I see the amount and thickness of rebar you use on your 4 metre span, but so far the start of the column from the footing with just 9 mm deformed rebar won't cut the weight over the distance, then add to it the weight of the pre-stressed slabs and it's very bad engineering practice and the reason so many buildings in Thailand collapse or tilt during the wet season.
Before I built my house my wife and I went around Bangkok looking at houses and how they were built. I revisited some of those houses after the floods and found about 3% were not fit to live in any longer because of all the corner cutting. I'll defy you to use a one tonne (1,000 kg) block and chain to lift that 4 metre beam unless it's going to be the skinniest beam in the house with no rebar and no gravel and sand added. Your calculations are not correct, I'd have a rethink.
Don't forget all the weight will end up at the joints of the column and beam, which is why engineers/building inspectors always look for hairline cracks at those joints before declaring a building unsafe.
But as I said, it's your build and I'm just trying to help.
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