Pilings for house, ground too compacted to sink

[kuma]

13 hours ago, VocalNeal said:

 

It is a local corruption of the North American expression "backhoe".  In UK "JCB" A tractor mounted digging bucket.

Here can also be used to describe an excavator. (trackhoe)

 

Even if you say backhoe in your own dialect it will be understood.

Man i hope in the UK they dont have to say ' a tractor mounted digging bucket' lol.

Are JCB that ubiquitous in the UK? The Kleenex of backhoes...hahaha

[kuma]

13 hours ago, sometimewoodworker said:

You were given bad advice to install pilings, if you did a soil bearing test, which I did, you would find if the soil is sufficient to bear the weight of the house and pad footings, no pilings, would easily be sufficient

 

My house build including the soil bearing test done by a local university professor with his engineering students is in the build story at http://bit.ly/NJnewHouse

 

There is a common misconception that houses need pilings, this is very dependent on soil composition. In Bangkok, because it’s soft mud you absolutely need them, many other places don’t.

 

Two of mine.

Thanks Wood. I have to slap myself on this one. Its been so long since I did a major project of any sort in Thailand, and I forgot, it seems, about how careful you need to be at times, with every step. As you and others have mentioned, I will look into contacting an engineer to get a second opinion. I get the feeling that the proposed solution is fine for the house in question - it is not palace sized or red brick walled.

Luckily we had end of days rain again today, so that stopped any progress so I am not holding them up as we move along here. I want to get to a good place in my head on this before they set those footings.

Cheers for the input

[kuma]

13 hours ago, millymoopoo said:

Yep, been through this one before with Thai builders, 2016 Chiang Mai (San Patong).

I wanted a slab, but oh no, 'can't do'...!

Builder wanted 1.2m piles, the other half (who's never built a house before) wanted 2m, straight down into the clay and into the water layer, how smart was that..?

Now the house is cracking up annually as the clay swells and contracts with the seasons.

Thai builders just can't understand that an 'umbrella' slab (150mm slab with 400mm footings around the extremities) floats intact on the clay thus keeping the walls/roof stable, avoiding cracking..!

So easy and cheaper..!

We are building a raised floor, one metre above grade, so in this instance that solution would not work. Thanks for sharing that thou, might be of interest to others building on grade.

Cheers

[kuma]

8 hours ago, Elkski said:

But a soil bearing test will only  test the tip layer.  The op said this is fill 17 ,years ago. We don't know how deep the fill is.  What the underlying soil is. Do we really trust  words that it was compacted?  How throughly if so.   Does time compact well enough.  I dont think a backhoe can install piles correctly.  Max  of it weight.   Need a proper pile driving machine.   Clay does swell and contract.  Good luck.  

So far we have excavated two metres deep, and at that point tried to sink the piles (sorry I keep calling them pillars) and as mentioned would not budge.

See the video I posted above, sometimes not even backhoes are used...I wonder how that house is sitting now!?

Good luck is always welcome, hoping it goes well.

Cheers

[kuma]

8 hours ago, Dragonboat Ronin said:

Tempted to say for a 1-story bungalow your likely ok. Personally i prefer to do the job as right as possible from ground up. How long-term are you thinking; is there a possibility of adding 2nd floor in future or increasing building size? Also worth considering how the land on your plot is affected by inevitable changing & flooding conditions. Respect to anyone undertaking challenge of building their own home in Thailand.

Hi thanks for your comments. So up front, I decided to build a minimalist home. For a few reasons: no kids and no plans; want as much space as possible for garden, fruit trees etc. Plan to add a wrap around balcony - but detached from the house completely. It will have an outdoor kitchen and I want it free standing so when in use there is not vibration in the house. In our current rental, whenever the wife is pounding away making som tum etc, the walls here carry the sound and even vibration of the mortar pounding - to me making that balcony free standing will stop that. Also will put aircon under the house on the ground. Currently the rental has a wall mounted unit and same thing, sound and vibration.

I am having a second bathroom built that is also free standing, on the edge of the parking area, I find it very useful to have a mud room like that (including a shower) so can clean off after working, bike ride, heavy rain etc, before entering the house.

No plan to add a second floor, but I might in future build another structure, a small office for me to hang out in, and that might be two story - but separate.

For flooding I have raised the floor one metre - if it gets worse than that I could be in trouble - but we are on a slope and have a big khlong that originates in the hills behind us and goes right past the house to the river and then the estuaries leading to the gulf, so the water has a great path already. The locals say the khlong and the slope has meant no flooding in that zone as far as anyone can recall. I grew up on a flood plain so know well what the water can do if it wants to.

Cheers

[Mambowoman]

This is how we do it in Kenya. Also, I give a little a swimming video.

 

 

[Cake Monster]

14 hours ago, Cake Monster said:

Your " Piling Posts " seem to me to not be what you say.

They look in the Photo like the posts used on fencing .

The Posts are put in then a " Panel " of about 5Cm thickness is slid down the slots to form a wall out of them.

My House is not piled. The Foundations are " Pad and Beam " Ie A reinforced Pad 1.4 M Sq x 80cm thick into the ground 1.5 M, and a reinforced Post 80 cm Sq coming off vertically, and all posts locked together with a Beam of Reinforced Concrete 80 x80cm at floor level.

My bad - Apologies - Senior Moment

Not 80 CM as stated - 20 Cm = 8"

 

[sometimewoodworker]

16 hours ago, Elkski said:

But a soil bearing test will only  test the tip layer.

Do please understand what you are talking about. Your comment is absolutely wrong.(apart from the misspelling). You can see the way my soil bearing test got the cores that went back to the university lab for analysis in the link I posted.

 

16 hours ago, Elkski said:

Does time compact well enough

Yes it does, depending on the fill, and in a shorter time than 17 years. Ours was rock hard in 7 years.

Edited October 28, 2020 by sometimewoodworker

[jojothai]

10 hours ago, kuma said:

We have excavated almost 2m down now, and from there they tried driving the pillars in - but they would not penetrate the soil, even with a steel bit added to the tip.

Appreciate the input, cheers

If you have done that then you should have no problem. You have found that the piling is not necessary. 
The construction you say is also not heavy loading.
Because you are stilting the house up 1 m, you should use pad footings with short post up to floor level where the beams are.
I am a civil engineer and IMHO there is no need for piles or a plate bearing test. 
One way that ground used to be tested for bearing in old times was by using a peg, normally wooden about 2 inch square pointed, and check if you can push it into the ground by hand. See how far it will go. It should only go in a small amount for the surface penetration then not more as you keep the pressure on. From what you say, you should have no problem.
I built my house on solid clay bedrock 0.8 to 1.5 m down, but there is a water seepage path at the clay level that had weakened the clay in some places. I trained the local people to use the peg check on the excavated area of the pad footings to ensure that they took out any clay that was not solid enough.
I have had no problems.

 

[millymoopoo]

11 hours ago, kuma said:

We are building a raised floor, one metre above grade, so in this instance that solution would not work. Thanks for sharing that thou, might be of interest to others building on grade.

Cheers

Well there'd be nothing stopping you from using 1M concrete posts included within the slab to build the house on.!

There's another advantage of the slab design, it brings the floor to ground temperature, which is usually way cooler than outside air temperature, thus a naturally cool house.

It's why most Thais with old traditional teak houses built on stilts, live underneath during the day and upstairs at night.

Stupidly our Thai builder put little 40cm high foundations all under the house, then placed concrete tiles on them to form a base and poured a 60mm slab over to create the floor, thus raising the floor 40cm above the ground, loosing any cooling effect, we now have air conditioners..!

[jojothai]

Picture here shows a hole where we had to dig deeper because the clay was too loose, You can see the layers of different ground on the sides and where the clay starts. I had to get them to dig an extra 20cm or so to get to where the base was solid enough.
So best to ensure they check for any loose areas.

 

[jojothai]

If it is stilted, Some pictures that may help you see how it goes.
 

[jojothai]

5 minutes ago, millymoopoo said:

There's another advantage of the slab design, it brings the floor to ground temperature, which is usually way cooler than outside air temperature, thus a naturally cool house.

Thats true, but depends if when stilted the gap is closed all around. Many thais do, but that can bring other problems, primarily damp, especially if there is minor flooding. I have seen that many times.
The other option is to leave the space open and the airpath keeps the floor cool.
I have the surround open, it has some other benefits and some drawbacks.
I do not get any damp. My drainage pipes are hung from under the slab and I can get to them for any problem, They go underground near the edges of the house. Also my main electrical cables and some wiring added for earthing and satellite cables the same (surface conduit fixed under the slab).
I store all old construction spare materials under parts of the house.
Drawbacks, rats can get around more easily to different places. Snakes, lizards and insects get under the house.
Essential to check an area before going under. I have the underside well sprayed each year for insects / termites.

[scorecard]

On 10/27/2020 at 1:32 PM, KannikaP said:

In English it's a digger!

An Australian soldier?

[Humpy]

 My house construction was similar to Jojothai's. Our house was built on farmland. 76 holes were dug to take the base of the 'posts'. No premix concrete was used. Mixed on site with the builder's own machine and carried in buckets to fill the 76 holes and beam form-work !!! The roof tiles are concrete as the lightweight roofing we see today was not available then. Pre-cast concrete 'slabs' were use for the floor base and then concreted over with a 3'' layer .. Cavity wall throughout ie brick outer wall and Q- CON block for the inner wall. (keeps the house cool )..I hate to think how many tons are being supported by the 76 'posts' !! Piling was not even considered ! House still standing 12 years on... Good luck with your build..... show us the result on completion .

[kuma]

17 hours ago, Cake Monster said:

My bad - Apologies - Senior Moment

Not 80 CM as stated - 20 Cm = 8"

 

Hey thanks for the update. I had quite the conversation about that with an engineer today, mentioning I had heard of a project using 80cm thick footings. haha, he was quite shocked. Now I understand why, for a house such as this that would be a bit much.

Cheers

[kuma]

13 hours ago, jojothai said:

If you have done that then you should have no problem. You have found that the piling is not necessary. 
The construction you say is also not heavy loading.
Because you are stilting the house up 1 m, you should use pad footings with short post up to floor level where the beams are.
I am a civil engineer and IMHO there is no need for piles or a plate bearing test. 
One way that ground used to be tested for bearing in old times was by using a peg, normally wooden about 2 inch square pointed, and check if you can push it into the ground by hand. See how far it will go. It should only go in a small amount for the surface penetration then not more as you keep the pressure on. From what you say, you should have no problem.
I built my house on solid clay bedrock 0.8 to 1.5 m down, but there is a water seepage path at the clay level that had weakened the clay in some places. I trained the local people to use the peg check on the excavated area of the pad footings to ensure that they took out any clay that was not solid enough.
I have had no problems.

 

Goo day thanks for the input. No one has pulled out a peg as yet to do a test but I know from trying to drive some stakes in the ground to that it is very solid (hows that for technical haha), in some cases the stake broke apart from hammering on it rather then penetrate the soil...hope we end up ok. 

Cheers

[kuma]

13 hours ago, millymoopoo said:

Well there'd be nothing stopping you from using 1M concrete posts included within the slab to build the house on.!

There's another advantage of the slab design, it brings the floor to ground temperature, which is usually way cooler than outside air temperature, thus a naturally cool house.

It's why most Thais with old traditional teak houses built on stilts, live underneath during the day and upstairs at night.

Stupidly our Thai builder put little 40cm high foundations all under the house, then placed concrete tiles on them to form a base and poured a 60mm slab over to create the floor, thus raising the floor 40cm above the ground, loosing any cooling effect, we now have air conditioners..!

Thanks for that input. We closed on the idea of leaving the ground under the house as it is, or maybe put some gravel there - still TBD. It is only 1M so not the traditional stilt style where you have living space underneath. I like that design, but we plan to be in and out many times per day and as such do not want the hassle of the stair climb. I will have one air con no matter what, I live thru the day without air but at night need a blast to get to sleep. Appreciate the input, cheers

[kuma]

12 hours ago, jojothai said:

Thats true, but depends if when stilted the gap is closed all around. Many thais do, but that can bring other problems, primarily damp, especially if there is minor flooding. I have seen that many times.
The other option is to leave the space open and the airpath keeps the floor cool.
I have the surround open, it has some other benefits and some drawbacks.
I do not get any damp. My drainage pipes are hung from under the slab and I can get to them for any problem, They go underground near the edges of the house. Also my main electrical cables and some wiring added for earthing and satellite cables the same (surface conduit fixed under the slab).
I store all old construction spare materials under parts of the house.
Drawbacks, rats can get around more easily to different places. Snakes, lizards and insects get under the house.
Essential to check an area before going under. I have the underside well sprayed each year for insects / termites.

Jojo great input, thanks. I pondered for a long time the idea of enclosing the raised floor, as you mention it is often done here. For the reasons you mention and more, I do not understand why its done other than aesthetics. It would be a headache for me and I want the space for air con, light storage, dogs etc so will leave it open.

Cheers

[kuma]

10 hours ago, Humpy said:

 My house construction was similar to Jojothai's. Our house was built on farmland. 76 holes were dug to take the base of the 'posts'. No premix concrete was used. Mixed on site with the builder's own machine and carried in buckets to fill the 76 holes and beam form-work !!! The roof tiles are concrete as the lightweight roofing we see today was not available then. Pre-cast concrete 'slabs' were use for the floor base and then concreted over with a 3'' layer .. Cavity wall throughout ie brick outer wall and Q- CON block for the inner wall. (keeps the house cool )..I hate to think how many tons are being supported by the 76 'posts' !! Piling was not even considered ! House still standing 12 years on... Good luck with your build..... show us the result on completion .

Humpy, thanks - great photos, very clear. 76 pilings, I get tired just thinking about it. This house will be the size of just one wing that you have there, lol. That steel for the roof (trusses?) must be 10x the weight of the entire thing I am building here. The plan here is to do the floor in precast with a topper as well.

No pilings, that is great to hear. Tomorrow the builder is going to give the pilings a go again, as there was heavy rain so he wants to try and see if that has softened the soil at all - will be interesting.

Thanks for the input, hope you are not having to cut all that grass, lol

Cheers

[jojothai]

The floor is done with the precast planks and concrete topping. The Planks have to be welded together at points provided to give the strength necessary during construction and placing the topping. 
The height 1 m above ground is about right in my opinion, my house was the same and I find i can get under without much difficulty. Picture here to show how part of it looks with the gap.

 

[Humpy]

Hello kuma, who will be installing all your electrical work ? The ''electricians'' that I had first had little idea of the power needed to run all the aircons, multi point heaters , water and well pumps and swimming pool pump....... and had no idea what a ring - main was !.... they were asked to leave !! I managed to get a professional electrician who knew what he was doing and all is OK.

The local ''plumbers''  were unfamiliar with hot water plumbing so I installed the whole lot.... hot and cold for  5 toilets, 3 en-suites , two kitchens and bar.  All pipework was under the floor as it was 1 meter above  ground. The builder had not seen a septic tank system connected to a drain-field so I had to show them what to do !!.... Again , I did all the pipework  for the two 1400 litre septic tanks and their drain fields...... they know now !.... 

I would certainly  seek the most qualified tradesmen for your build..... and perhaps view some of their previous work !! Good luck......  please let us see your house when completed.

[kuma]

14 hours ago, jojothai said:

The floor is done with the precast planks and concrete topping. The Planks have to be welded together at points provided to give the strength necessary during construction and placing the topping. 
The height 1 m above ground is about right in my opinion, my house was the same and I find i can get under without much difficulty. Picture here to show how part of it looks with the gap.

 

Jojo, house looks great. Is the gap under still at 1m or has there been some fill added since? My old eyes are failing me, looks like less than a metre? I am expecting the floor to be at about my waist height...maybe that white skirt around the perimeter is blocking the true height? 

Nice looking place, sure you are enjoying it.

Cheers

 

[kuma]

13 hours ago, Humpy said:

Hello kuma, who will be installing all your electrical work ? The ''electricians'' that I had first had little idea of the power needed to run all the aircons, multi point heaters , water and well pumps and swimming pool pump....... and had no idea what a ring - main was !.... they were asked to leave !! I managed to get a professional electrician who knew what he was doing and all is OK.

The local ''plumbers''  were unfamiliar with hot water plumbing so I installed the whole lot.... hot and cold for  5 toilets, 3 en-suites , two kitchens and bar.  All pipework was under the floor as it was 1 meter above  ground. The builder had not seen a septic tank system connected to a drain-field so I had to show them what to do !!.... Again , I did all the pipework  for the two 1400 litre septic tanks and their drain fields...... they know now !.... 

I would certainly  seek the most qualified tradesmen for your build..... and perhaps view some of their previous work !! Good luck......  please let us see your house when completed.

Humpy

Wow I hope to have better luck than you in terms of experienced trades - as I would not be able to take on the plumbing or electrical on my own. I did do a tour and visited with six different builders and viewed their previous work before choosing this team. I hope all that leg work is going to pay off. They have already prepared the septic and drainage areas. I will go with a single 1000L bulb to start, for two bathrooms and a kitchen. Plan is to add a second if all goes well and we stay and further grow the property.

If you are still on the tools maybe I should ring you up for a hand, in case things go south, lol. Kidding, I am pretty confident with this guy, and we have a lot of assistance from the Tessaban office, so they are talking to us and the builder on the project and even dropping by to see it - very nice place here, lots of very nice and helpful people. One day left before Loy Krathong, tomorrow they will make one more attempt to sink the piles, since that was the plan and they are on site...even though now its pretty much universally agreed they are not really necessary. My Pops liked to overbuild things, so I guess that rubs off a bit, haha

Cheers

[rumak]

On 10/27/2020 at 11:35 PM, kuma said:

Good day, thanks for that. Yes I spoke with the engineer at the Tessaban and they also suggested pilings were overkill for the structure we are building. The footings were to be 0.8 x 0.8 m of reinforced concrete but now they plan to expand them to 1.2 x 1.2m to give additional support. There are nine footings for a house of only 42sqm and the walls are Q-Conn, which is very light, plus the roof is modern style so again light weight. I did decide to build a small place first, to see how things would go - and wow so far happy I did that. 

Pondering calling up a local engineer to get their input, but wonder if it will be $ well spent?

Cheers

so basically this "house"  is  6 meters  X    7 meters .     i think you are definitely overthinking it, can understand since sounds like first build here.    Info above sounds more than sufficient.    

Very curious what this structure is costing you.      My guestimate would be under 500K.  This going to be a "guest house"  in the future ?  after you build the dream house ?

Edited October 29, 2020 by rumak

[kuma]

3 minutes ago, rumak said:

so basically this "house"  is  6 meters  X    7 meters .     i think you are definitely overthinking it, can understand since sounds like first build here.    Info above sounds more than sufficient.    

Very curious what this structure is costing you.      My guestimate would be under 500K.  This going to be a "guest house"  in the future ?  after you build the dream house ?

Nope, this is the last house, been many before and still a few on the books - but this spot is for the last stand. The only guests that will ever grace it are the two of us. Might build an additional 'office' space later if feel up to it, but the idea is to be outside and the land is pretty much all planned out for fruit and other gardening so this might be it. 

Cheers

[rumak]

4 minutes ago, rumak said:

I did decide to build a small place first, to see how things would go -

 

hmmmmm

[kuma]

10 minutes ago, rumak said:

 

hmmmmm

Sleep is your friend....????

[Crossy]

17 hours ago, Humpy said:

and had no idea what a ring - main was !

 

Do not under any circumstances install a UK style ring-final with Thai outlets!

 

Conflagration awaits.

[Curt1591]

The ground around the houses in our little moo baan is rock hard. The pilings were place by the classic pile driver. 

All the concrete around the moo baan, without pilings, has cracked due to settling. 
 

Water finds a way ....