Land Fill - How Long To Settle?

[JaiLai]

I know a pretty vague question BUT how long after land fill should you wait before building starts?

Is there a general rule of thumb, 1 wet season? 2?

How do you know when the land fill has completely settled?

Thanks.

[LennyW]

Pretty much irrelevant, as housing foundations should be piled to hard level anyway. Pile each post, cant go wrong.

Some want to build concrete slab type foundations???? and NEED the ground to settle - forget it!! Slip form pile and rest easy!

[JaiLai]

Pretty much irrelevant, as housing foundations should be piled to hard level anyway. Pile each post, cant go wrong.

Some want to build concrete slab type foundations???? and NEED the ground to settle - forget it!! Slip form pile and rest easy!

Thanks for the advice, well noted.

[oxymoron]

Most of Thailand is heavy clay, certainly fill is. That is why you use "pile" or "pile to 1metre square footings at bed soil". You could wait until hell freezes and you will not get a base suitable for "slab on ground" construction.

[Crossy]

We're on riverside clay (the site was a brick works), piles were driven until friction prevented them from going deeper (there's a technical term which I forget) most went to between 12 and 14m.

The high load foundations are on two piles, the rest on single, both with a reinforced concrete pile cap upon which the structure sits.

You should consult contractors / architects / structural engineers with local knowledge to decide what your particular location and structure needs.

[JaiLai]

We're on riverside clay (the site was a brick works), piles were driven until friction prevented them from going deeper (there's a technical term which I forget) most went to between 12 and 14m.

The high load foundations are on two piles, the rest on single, both with a reinforced concrete pile cap upon which the structure sits.

You should consult contractors / architects / structural engineers with local knowledge to decide what your particular location and structure needs.

Thanks for the input.

[Pib]

I always heard to let dirt settle approx 2 years before building on it unless you can pack it down with heavy machinery. And for Thailand's wet soil additional support measures are usually required to minimize foundation movement/settling. Here in my Bangkok moobaan the developer drives concrete piles down 3 to 4 meters at spacing of every few meters then lays the concrete foundation on top of these piles. Does the same thing for the home's perimeter concrete fence. Definitely no shortage of pile driving. My house is approaching 5 years old and was built this way...no foundation problems or wall/floor tile cracks anywhere so far.

[dave111223]

Pretty much irrelevant, as housing foundations should be piled to hard level anyway. Pile each post, cant go wrong.

Some want to build concrete slab type foundations???? and NEED the ground to settle - forget it!! Slip form pile and rest easy!

But you don't really want your house to be on stilts with a big sinkhole under neither after 6 months do you...

We left our fill to settle for 1 year and it probably dropped by 20cm.

[dave111223]

Here in my Bangkok moobaan the developer drives concrete piles down 3 to 4 meters at spacing of every few meters then lays the concrete foundation on top of these piles. Does the same thing for the home's perimeter concrete fence. Definitely no shortage of pile driving. My house is approaching 5 years old and was built this way...no foundation problems or wall/floor tile cracks anywhere so far.

3-4 meters I'd be seriously worried!!...the piles for our house are 22meters... 18meters was considered minimum by all the builders we talked to.

[Pib]

Here in my Bangkok moobaan the developer drives concrete piles down 3 to 4 meters at spacing of every few meters then lays the concrete foundation on top of these piles. Does the same thing for the home's perimeter concrete fence. Definitely no shortage of pile driving. My house is approaching 5 years old and was built this way...no foundation problems or wall/floor tile cracks anywhere so far.

3-4 meters I'd be seriously worried!!...the piles for our house are 22meters... 18meters was considered minimum by all the builders we talked to.

22 meters (72 feet) !!!!??? That's taller than light/electric poles. What are you building on? Mush?

[trogers]

Here in my Bangkok moobaan the developer drives concrete piles down 3 to 4 meters at spacing of every few meters then lays the concrete foundation on top of these piles. Does the same thing for the home's perimeter concrete fence. Definitely no shortage of pile driving. My house is approaching 5 years old and was built this way...no foundation problems or wall/floor tile cracks anywhere so far.

3-4 meters I'd be seriously worried!!...the piles for our house are 22meters... 18meters was considered minimum by all the builders we talked to.

22 meters (72 feet) !!!!??? That's taller than light/electric poles. What are you building on? Mush?

The first layer of load bearing soil stratum in Bangkok varies from 16m to 24m below ground level, from Rangsit towards the sea.

The answer to this post depends on a few factors:

- condition of existing ground

- height of fill

- type of structure to be built on the ground, hence the load that will be imposed on the soil.

Edited September 30, 2012 by trogers

[transam]

3 years but the building upright pads must be on natural compacted earth.

[dave111223]

Here in my Bangkok moobaan the developer drives concrete piles down 3 to 4 meters at spacing of every few meters then lays the concrete foundation on top of these piles. Does the same thing for the home's perimeter concrete fence. Definitely no shortage of pile driving. My house is approaching 5 years old and was built this way...no foundation problems or wall/floor tile cracks anywhere so far.

3-4 meters I'd be seriously worried!!...the piles for our house are 22meters... 18meters was considered minimum by all the builders we talked to.

22 meters (72 feet) !!!!??? That's taller than light/electric poles. What are you building on? Mush?

It's basically 2 phone poles stacked end on end. They bang the first one in, then weld the second on top and bang that in too. Some of the piles could have gone deeper, but met the required blow count.

Here's a picture of the surface we were building here, and the piling being driven (note that the pile in the picture is only half of the total 22m).

Edited October 1, 2012 by dave111223

[Pib]

Yea, I've seen plenty of those around. Guess in all depends on your location, type of ground, foundation type, building structure, etc.....just as trogers mentioned above. To tell you the truth, when I bought my house it was 80% done and the other 11 houses on the soi well underway. Maybe they did sink much longer piles. When they built the mini soccer field enclosure they did sink piles approx 8 meter long around the perimeter where they later mounted the metal light poles. They first used a long metal spike which looked like a 10 foot long railroad spike, pressed that spike into the ground with the backhoe, then removed the spike, and then press in the concrete pile.

Additionally, they recently started laying the ground work for a new batch of houses, and they have already sunk the piles for the perimeter fences and they were 3-4 meters in length...and pressed into the ground every approx 2 to 3 meters...walked by them daily in walking the dogs and watching them use a backhoe to press the piles into the ground. My moobaan is probably around 20 years old and the land owner/developer has been the same one building almost all the houses every since....I almost bought one 17 year old house in the moobaan also originally built by the developer, but instead ended up buying a new one from him...but the 17 year old one didn't have any structural/sinking problems...haven't seen any other houses in the moobaan with any outside structural problems either. They also build the house with terminte treatment piping laid in the foundation, so you can periodically pour in/shoot in treatment. Yeap, no complaints on the structure by me...and haven't heard any neighbors complain either after living here 4 years. Cheers.

[mrbojangles]

Difficult to answer without kowing the type of land in the area but the longer the better really and I'd say at least a wet season. We did ours and left it for about 3 years to settle although we have since put more on the top.

[Khun Jean]

Build on the original land that probably has hundreds of years to settle. Then backfill.

A floating raft foundation is another way, it will actually 'float' on the land and will stay afloat because it displaces more then it weighs.

All depends on the soil condition. Building a lighter home, steel, superblock etc will also help to minimize settlement of the building .

[cheeryble]

Build on the original land that probably has hundreds of years to settle. Then backfill.

A floating raft foundation is another way, it will actually 'float' on the land and will stay afloat because it displaces more then it weighs.

All depends on the soil condition. Building a lighter home, steel, superblock etc will also help to minimize settlement of the building .

This seems the easiest way but presumably you still have to dig for a support layer.

Out of great interest how much does piling cost?

It's not that deep up here in CM is it?

[rgs2001uk]

Build on the original land that probably has hundreds of years to settle. Then backfill.

A floating raft foundation is another way, it will actually 'float' on the land and will stay afloat because it displaces more then it weighs.

All depends on the soil condition. Building a lighter home, steel, superblock etc will also help to minimize settlement of the building .

This seems the easiest way but presumably you still have to dig for a support layer.

Out of great interest how much does piling cost?

It's not that deep up here in CM is it?

Depends on the length, a normal house being built in Bkk with 16 piles going in at an average of about 20 meteres in length at a cost of roughtly 13,500 per pile will add an extra 210xxx baht to your cost.

Dave111 has already provided relevant info.

[Pib]

Here's how one Thai home builder describes a pile sinking requirement/method...see the foundation paragraph: Link

[cheeryble]

Thankyou both for that....

Wow 200,000 is a very considerable percentage of a build cost.

Is 20m typical or is BKK extra deep? I had imagined much less.

Anyone know what is a typical depth for piles up here in CM?

[Pib]

I expect it's not so much the cost of the rebar-enforced concrete piles since concrete products are pretty cheap in Thailand, but the machinery transport/setup/use/teardown and labor. Wouldn't surprise me if the cost of driving one 9 ft pile wouldn't be that much cheaper than driving two 9 ft piles on top of each other. But hey, I'm making an assumption...and I guess it will all depend on how they price out subcomponents of a job. That is, transport/setup/use/teardown equals so much cost, the labor time cost, the concrete pile cost, etc.

[Pib]

Whoops...where I mentioned 9 ft several times above, the brain was saying 9 "meters" but the fingers errored by typing 9 "feet." I blame it on Chang beer.

[Pib]

Yea, I've seen plenty of those around. Guess in all depends on your location, type of ground, foundation type, building structure, etc.....just as trogers mentioned above. To tell you the truth, when I bought my house it was 80% done and the other 11 houses on the soi well underway. Maybe they did sink much longer piles. When they built the mini soccer field enclosure they did sink piles approx 8 meter long around the perimeter where they later mounted the metal light poles. They first used a long metal spike which looked like a 10 foot long railroad spike, pressed that spike into the ground with the backhoe, then removed the spike, and then press in the concrete pile.

Additionally, they recently started laying the ground work for a new batch of houses, and they have already sunk the piles for the perimeter fences and they were 3-4 meters in length...and pressed into the ground every approx 2 to 3 meters...walked by them daily in walking the dogs and watching them use a backhoe to press the piles into the ground. My moobaan is probably around 20 years old and the land owner/developer has been the same one building almost all the houses every since....I almost bought one 17 year old house in the moobaan also originally built by the developer, but instead ended up buying a new one from him...but the 17 year old one didn't have any structural/sinking problems...haven't seen any other houses in the moobaan with any outside structural problems either. They also build the house with terminte treatment piping laid in the foundation, so you can periodically pour in/shoot in treatment. Yeap, no complaints on the structure by me...and haven't heard any neighbors complain either after living here 4 years. Cheers.

OK, yesterday I was able to confirm with the engineer who built my house how deep the columns/poles under the foundation of my Bangkok home are: 17 meters.

The engineer who built my house is also doing some concrete pad work around parts of the house for me right now. For these concrete tiled pads (which will only be supporting their own weight and anybody walking on them) they are sinking concrete poles 2-3 meters long and spaced approx 1 meter apart.

A new house is being built a few blocks from me and they (different builder) did not pound-in concrete poles. Instead they first drilled/dug holes approx 40 centimeters in width and approx 15-20 meters deep, they then dropped the prepared rebar structure/box into the hole, and then a concrete truck poured concrete down the hole till full.

[monty]

Yea, I've seen plenty of those around. Guess in all depends on your location, type of ground, foundation type, building structure, etc.....just as trogers mentioned above. To tell you the truth, when I bought my house it was 80% done and the other 11 houses on the soi well underway. Maybe they did sink much longer piles. When they built the mini soccer field enclosure they did sink piles approx 8 meter long around the perimeter where they later mounted the metal light poles. They first used a long metal spike which looked like a 10 foot long railroad spike, pressed that spike into the ground with the backhoe, then removed the spike, and then press in the concrete pile.

Additionally, they recently started laying the ground work for a new batch of houses, and they have already sunk the piles for the perimeter fences and they were 3-4 meters in length...and pressed into the ground every approx 2 to 3 meters...walked by them daily in walking the dogs and watching them use a backhoe to press the piles into the ground. My moobaan is probably around 20 years old and the land owner/developer has been the same one building almost all the houses every since....I almost bought one 17 year old house in the moobaan also originally built by the developer, but instead ended up buying a new one from him...but the 17 year old one didn't have any structural/sinking problems...haven't seen any other houses in the moobaan with any outside structural problems either. They also build the house with terminte treatment piping laid in the foundation, so you can periodically pour in/shoot in treatment. Yeap, no complaints on the structure by me...and haven't heard any neighbors complain either after living here 4 years. Cheers.

OK, yesterday I was able to confirm with the engineer who built my house how deep the columns/poles under the foundation of my Bangkok home are: 17 meters.

The engineer who built my house is also doing some concrete pad work around parts of the house for me right now. For these concrete tiled pads (which will only be supporting their own weight and anybody walking on them) they are sinking concrete poles 2-3 meters long and spaced approx 1 meter apart.

A new house is being built a few blocks from me and they (different builder) did not pound-in concrete poles. Instead they first drilled/dug holes approx 40 centimeters in width and approx 15-20 meters deep, they then dropped the prepared rebar structure/box into the hole, and then a concrete truck poured concrete down the hole till full.

The latter is often done in built up areas as the standard concrete pile driving can damage surrounding structures.

This way is rather more expensive as well.

Depending where in Thailand for a 35cm you'd pay around 10,000 Baht/10 meters depth...

[monty]

Looks like this

[Pib]

Looks like this 1363356377346.jpg

Yeap...that's the tripod assembly they use...plus the one they were using in my moobaan had a big diesel power generated powering the electric motor that operated the pipe/casing pounding and digging device which is part of the tripod assembly. I've got several pictures like above on my smartphone. When I mentioned drilling/dug a hole they use screw-together pipes approx. 40cm in diameter and around 1.5-2 meters long...pound that into the ground using above tripod assembly with special heavy adapter lifted up and down by a motor and pulley assembly, screw on another approx. 2 meter pipe section...pound it in....and after they have enough sections pounded in (like beating a pipe into the ground) they repeatedly drop & retrieve a digging device down the pipe assembly to remove the dirt from the middle of the pipe....then they extract the pipe sections used to dig the hole...drop in the assembled rebar structure...and then let the concrete truck fill up the hole.

I watched them make a couple of holes and it really don't take that long for them to dig an approx. 20 meter deep hole. Although there is some pounding it's not really loud at all nor do you feel any earth shaking...but the electric motor/gear assembly powered by a diesel generator they use to pound & dig is pretty noisy.

[monty]

The one in my picture is pneumatically powered with a big diesel powered air compressor.

They're doing around 4 per day, going 15 meter deep.

[dave111223]

The drilling method you mentioned has to be used if there are other buildings too close to the piles, in which case driving the piles may cause damage to the other buildings.

It's more expensive to drill...so it appears your neighbor is the caring sort...

The definition of "too close" is often hotly debated between the new building and the existing close buildings

[David48]

Great OP and just to let you know ... sometimes the Thai's take the shortcuts themselves and end up paying the consequences.

The Farmhouse where the gf lives is slowly sinking at one end.

Lightweight timber structure over timber poles, but the land at one end of the house was reclaimed from a former pond and thus slowly sinking.

Doors jamming, windows can close ... real problem and not much they can do about it.

[cycloneJ]

The Farmhouse where the gf lives is slowly sinking at one end.

and on a larger scale:

An eight-storey building complex under construction in Rangsit has taken on quite a lean

- even more bamboo scaffolding won't save this one, it. and its partner building opposite, look to be goners.

pictures in Thai news media here (Khaosod) and here (Thairath)

I'm not familiar with the area - likely to be filled/reclaimed land?