Fill Dirt

Hi guys,

My wife and I are getting really close to starting our house build. We are building in a well known moobahn where flooding is not an issue. Our contractor wants us to fill our land with dirt to level it all out and to make our property slightly higher than the street. He said if we only fill in about a meter of dirt than we don't need to worry about leaving it to settle, and can start building on it almost immediately.

Any thoughts on that? Most everything I read on here says to leave it to settle for a while before building.

Thanks

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Originally Posted by Ganesh

We are building in a well

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Originally Posted by Ganesh

Any thoughts on that?

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Wetter the devil you know.

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Originally Posted by Ganesh

He said if we only fill in about a meter of dirt than we don't need to worry about leaving it to settle, and can start building on it almost immediately.

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Sounds right. Having a few good rains on the fill is good however. Will let it settle a bit. You'll lose a bit to erosion but can replace before building.

Assuming a typical build, the fill will be bearing no weight when the house is constructed. Footings will be installed about a meter below the original ground level.

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Originally Posted by Ganesh

Our contractor wants us to fill our land with dirt to level it all out and to make our property slightly higher than the street. He said if we only fill in about a meter of dirt than we don't need to worry about leaving it to settle, and can start building on it almost immediately.

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of course you can do that, without building problems

but the land will settle around the house when the rains come, so don't build any permanent paths or terraces for a while

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Originally Posted by Ganesh

Our contractor wants us to fill our land with dirt to level it all out and to make our property slightly higher than the street. He said if we only fill in about a meter of dirt than we don't need to worry about leaving it to settle, and can start building on it almost immediately.

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He is dead wrong and do not let him leave without compacting that material.

You were right to question his method!

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Originally Posted by S Landreth

He is dead wrong and do not let him leave without compacting that material.

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Why? The fill will not be bearing any structural weight. As Andy says, fill needs to compact naturally or by machine so it can support concrete slabs or other structures with no footings but the house itself, no need.

Thanks for the input. The dirt was delivered today, and it only raised the property about 40cm. They leveled it all out with a tractor, which I suppose helped to compact it to. It will probably be a couple of weeks before we start building, and we will be digging piles into the ground (unsure how deep) so hopefully it will be fine.

I've just had similar for my build. I was wondering if it need to be left or not too.

It seems, listening to others, that the issue may be a cracking floor within a year or so if the earth 'moves' under the poured concrete slab. To avoid this, make sure the concrete slab is poured thick with plenty or rebar/mesh. I hasten to add that I don't come from a position of knowledge here, just advice of others who have been through the same/similar situations...

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Originally Posted by Ganesh

Hi guys,

My wife and I are getting really close to starting our house build. We are building in a well known moobahn where flooding is not an issue. Our contractor wants us to fill our land with dirt to level it all out and to make our property slightly higher than the street. He said if we only fill in about a meter of dirt than we don't need to worry about leaving it to settle, and can start building on it almost immediately.

Any thoughts on that? Most everything I read on here says to leave it to settle for a while before building.

Thanks

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I don't know if you want your house to sink into the dirt? If so, yes you should start building right now.
I myself am not taking any chances and will let someone drive some piles into the soil before we start. The only problem is I've got no idea how long the piles will have to be (since there's no company to "assess" the soil and depth of sand/rock layer).

Edit: In the Netherlands we always let the soil settle for at least 3 years, this is what happened to 1000 houses where they didnt let the soil settle for 3 years but only 1. Luckily there was no damage to the houses but it still costed a damn load of money. At most places the soil settled for more than 30cm in 4 years.

https://teakdoor.com/images/smilies1/You_Rock_Emoticon.gif

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Originally Posted by Koetjeka

I myself am not taking any chances and will let someone drive some piles

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You Hollanders are all the same.

The rule of thumb according to most Thais that I've spoken to, you need to let the fill settle for at least one to two years depending on where you live. You might have pilings in the ground but the fill under the house will settle more.

There are plenty of houses around me that were built WAY before the fill had settled and you can see gaps between the slab and the ground underneath. It's not my way of thinking to build a house.

The main reason that these guys in subdivisions build so early after filling is because THEY owe so much on their loans to the bank.

If time is not a problem, WAIT a year or two.

Thanks again. Like most things on the Internet, half of responders say it is ok, half say it is not, and I am left still confused and unsure.

The contractor doesn't work for the moobahn, so no worries about him trying to build fast to pay off debts.

^ it might come down to the area, type of soil, depth of hard ground, etc?

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Originally Posted by Ganesh

I am left still confused and unsure.

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Fair enough.
Police in Amsterdam - Harry Enfield and Chums - BBC comedy - YouTube

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Originally Posted by Bettyboo

It seems, listening to others, that the issue may be a cracking floor within a year or so if the earth 'moves' under the poured concrete slab. To avoid this, make sure

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make sure the ground under the house is filled with rubble and sand etc, not earth

it is not a good idea to build on soil, even if compacted

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Originally Posted by Eliminator

you can see gaps between the slab and the house

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I can't imagine that! unless the outside earth settled over 30 cm; you can always add more earth to cover if needed

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Originally Posted by Ganesh

Thanks again. Like most things on the Internet, half of responders say it is ok, half say it is not, and I am left still confused and unsure.

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well, half are right, the other half just listen to hearsay

if your columns/piles go down deep to a firm substrata, the fill has absolutely no bearing on the structure; the house is supported on those columns not any earth fill

as has been mentioned, any floor slab should not be laid on the earth fill, even if compacted. The area beneath the house should be filled with rubble and sand, then concreted

there is no reason that area will compact further as no rain will fall on it. Even if it did, due to flooding etc, the floor slab is strong enough to support it's own weight, the same as any above ground floors/ceilings

around the house you may find the earth will compact down and , if necessary, you can add more earth to build to the desired level

Why don't we have this problem in the west where most houses are built with shallow raft foundations...( since the quakes here in NZ deep piles have been added to give stability.)
Having proper drainage would be more important than compacting what is essentially settled ground.

As long as your foundations are excavavated deep enough to be supported by the original substrate soil, your house won't go anywhere. What has to be remembered is that the uncompacted fill material above the original soil will settle 20-25% over time. If you fill 1 meter then expect your finished ground level over a year os so to be down to about 800mm. This is the reason for leaving driveways, paths, etc. until the soil has settled.

For Static Preloading in solid ground (not much observed settlement) ... pile up a minimum 2X higher than what you want the final grade to be, for a minimum 6 months ... preferably 1 year. You can sell or spread the excess to grade the land falling away from the house to the perimeter water ditches. You should always install piles in Thailand. Probably 3.0m deep. Check to see if Footing Pads are required locally. If the local ground doesn't appear to be really stable (pvt/conc roads/hwys showing cracking) you should hire a good Local Civil Engineer to assess the Site. A few Thousand baht of research can save you a lot of money. Some places in Issan have salt water 2-3m below grade. You need to know this, as you don't want to penetrate the salt water level. Always be slightly higher than your neighbours. Don't be in a rush to install paved parking or road areas. These may require Dynamic Loading c/w a Heavy Duty Road Packer. No one wants to spend money on what they can't see underground ... but these costs are quite low in Thailand. Do it right if you intend to live there a long time.

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Originally Posted by cdnski12

For Static Preloading in solid ground (not much observed settlement) ... pile up a minimum 2X higher than what you want the final grade to be, for a minimum 6 months ... preferably 1 year.

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A simple cost benefit analysis would show this method would be ridiculous.


Renting a nice size single drum vibratory roller for a few hours (to compact a normal size lot for a home) would be cheaper than rent for one month (delay construction and moving into the new home).

In response to cdnski12 in post 19, I can understand the logic in "Always be slightly higher than your neighbours." However, I'm not sure about the communal responsibility of such actions.

What's happening now around where I live in a rural setting just outside a Thai regional city is that what was previously farm land (some rice but also other crops like mangos and market garden produce) is now being bought by 'professional' people and being filled for construction of their residences. The roads that used to support an occasional 'tak-tak' and sundry motorcycles are now being used by trucks transporting fill for these constructions and are suffering badly under the increased traffic. Also, and in direct regard to cdnski12's comment, the land is being raised above the levels of the surrounding land and the roads. After heavy rain, the water that I assume used to be absorbed by the farm land now ends up on the roads and adds to the problem of the increased heavy traffic.

In my particular case, I live on a small soi that is not sealed. Someone has bought a substantial piece of land (I would guess about 3 rai) along from me and filled it to a height of about 1m above the level of the soi. They are now in the process of building a massive Thai-style house. Opposite this construction, the same people bought a small piece of land (0.5 rai) - I think for the construction of a small house, possibly for a maid or someone similar - and last week filled this site to about 0.5m above the level of the soi. This week we have had heavy rain and that area is badly affected, maybe due to the heavy traffic use during the filling process but also due to the increased run-off. The effect is so bad that motorcyclists now avoid that section of road and my immediate neighbours don't venture that way as they drive a sedan (I've got a 4-wheel drive specifically bought to deal with such situations). I'm not sure what the effect is on land directly next to these developments.

On a similar note but a much bigger scale is the filling of land and construction of major shopping centres. This has just happened with the opening of Central outside of Ubon. The location is in what was previously part of the flood area of the Moon River so I'm not sure what will happen to this new development if we get a repeat of 2002 when the whole area was under water for 2 months.

It would seem that there needs to be some regulatory authority to oversee such situations as filling to a higher level than the neighbours may directly affect those neighbours. However, such an authority may already exist but not be very effective due to the same reasons that many regulations are not followed.

bobforest

Iv'e been going to Thailand for some 10 years now, it that time, I've noticed many ereas where the after thought surronding fences, foot path's etc, have dislodged, half fallen over, look like sh-t,,,,I put this down to poor foundations, unstable ground, really, I dont think you have need to be an engineer to figure that out.. My suggestion is hasten slowly, let it seattle, unless it is compacted with the appropriate heavy equipment and I have'nt seen that in Thailand all that much.

The same sort of thing is starting to happen out near my Mae Rim farm

lots of new plots being filled and the road will not take it as there are no proper drains or even foundations

should be interesting to see if the local council do something