Pilings for house, ground too compacted to sink

[kuma 148]

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 148]

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 148]

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 148]

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 148]

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 15]

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

 

 

[Cake Monster 4,470]

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 3,053]

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 517]

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 133]

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 517]

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 517]

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

[jojothai 517]

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 21,176]

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

In English it's a digger!

An Australian soldier?

[Humpy 325]

 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 .