Raising the Level of Land

[westerby]

Chaps,

I've noticed that a lot of people raise the level of their land, before construction, by two/three feet or more.

How long would you leave the new earth to settle before building, over two years or less?

[BobHelm]

Over 1 full wet season is the norm westerby.

[PopsIcafe]

My understanding, here they don't even wait one good wet season. Usually they start building 6 months later, after they have watered the land down, let it dry, several times. They run a big roller over it to quickly settle the land. This of course isn't the best way of doing it and the land hasn't really settled enough to build on it. I'm not an engineer but did read something on it. They were build new housing on base, once the land was cleared, and leveled, they waited 5 years before building on it.

Pop's

[saint]

if you pile the building which is the norm on newly filled land , waiting time of about 5 minutes. basically the house is built on stilts , but they are under ground on solid earth, usually between 4 and 6 metres depending on the fill level . cost in the region of 1800 / 2100 baht per pile, average 3 bed house between 22 to 26 piles needed.

[westerby]

if you pile the building which is the norm on newly filled land , waiting time of about 5 minutes. basically the house is built on stilts , but they are under ground on solid earth, usually between 4 and 6 metres depending on the fill level . cost in the region of 1800 / 2100 baht per pile, average 3 bed house between 22 to 26 piles needed.

OK, I'm unsure what you mean, can you explain further?

[BobHelm]

westerby this is what saint is talking about..

pillar.jpg (22.41 KiB) Viewed 5344 times

But, personally I do not agree with his claim that this means you can build on filled land straight away. You need to let the land settle & harden so that you do not get 'gaps' around the beams that tie these pillars together.
As pops says you can shorten the 'curing time' with use of heavy duty rollers.

[westerby]

Thank you, Bob.

[BobHelm]

This may be a better picture.
The first set of parallel lines you can see between the two pillars is cross beam that sits on the ground. The second set are another cross beam that the floor sits on. The area between these two beams is then filled (brick, concrete blocks, what ever) & cemented. So if the ground settles after you have built it is going to look pretty dam strange....

pillar.jpg (47.32 KiB) Viewed 5328 times

p.s. you don't have to have the second set of beams, you could build the floor directly on the first set - depends if you want the house raised above the landfilled level or not...

[westerby]

This may be a better picture.
The first set of parallel lines you can see between the two pillars is cross beam that sits on the ground. The second set are another cross beam that the floor sits on. The area between these two beams is then filled (brick, concrete blocks, what ever) & cemented. So if the ground settles after you have built it is going to look pretty dam strange.
p.s. you don't have to have the second set of beams, you could build the floor directly on the first set - depends if you want the house raised above the landfilled level or not...

OK, Bob, I see what you mean, thanks for that.

Pops and Saint, thank you....

[saint]

bob and westers, that drawing is of a pad foundation , which is only suitable for established ground , not filled . to do this foundation, they dig down to about 1.5 metres lay a concrete pad which includes the rebar for the pillars of about 60 cm deep. 60x60 . so you basically have a 60cm cube of concrete with the rebar embedded in it for the pillars sticking out of the ground. a pilled foundation is similar , but underneath this concrete pad you have 200 cm square reinforced concrete pins driven into the ground by machine to a depth of between 4 to 6 meters depending on the depth of your land fill . these pins are so deep that they are in solid clay , not affected by water in any way, and the house is constructed the same way as bobs drawing with the concete pad attached to these piles, but with only 1 floorbeam , and the pad only needs to be 1 m from the surface not 1.5 and basically sits on the piles . the only thing that actually sits on the ground is the wall between the underside of the floor beam and the ground , but you can even leave that open if required as it serves no structual significance , just makes it look pretty .

[BobHelm]

Thanks for that saint. Must admit that is new to me. Is this the system they use on the large estates???

[saint]

to my knowledge yes bob , i live on hansa and because the land fill is about 3 metres deep , they use 6 metre piles which are driven to 1 metre below the surface , making the bottom 7 metres deep in total .

[mighty-chang]

a bit over the top saint for wooden style thai house for the inlaws i wonder who financed it (me ponders)

[BobHelm]

The style of pillar I showed is exactly the same as used on wooden Thai Houses. Although much older properties would have used wooden pillars driven into the ground rather than concrete.
The floor level would also start about 2 meters above the ground level rather than at ground level.
This enabled a cooler area beneath the house for living in during the heat of the day. Traditionally this area was also used for the safe keeping of livestock at night.
Thai ingenuity, just in case anyone thought it didn't exist...

[AussieBoy]

Build on any thing you like and as soon as you like, the term used is Bored Piers, or driven piles, the depth of the piers if the fill has not been rolled vibrated compacted in layers of 300mm max, supervised by a qualified person , and the fill is clean, no composable matter, will depend on the soil type to start with, if you got a swamp and you roll fill compact the fill to 5 metres, then thats good, but you still got a swamp underneith,

The bored piers, if the soil will allow boring and not allow the soil to collasp into the hole, is usually the norm for domestic jobs, if the soil is to wet then driven piles are used

http://foundation-specialists.com/bored ... ge%202.htm

[FrazeeDK]

Aussie boy,

how about non-filled land that is primarily solid clay that is pretty much hard as rock.. We built our house on such a foundation with the T footed pillars put down about 1.75 meters.. It's been a year and I don't detect any settling cracks at all so would imagine that the land is quite solid enough for the depth of the footings..

[tigerryan]

soil compaction and the science around it is big business and is complicated stuff and is one of the first question that need to be answered before you set up a drill rig or big crane or something heavy. I dont know much about it outside of the obvious but one thing I have learned is that water in the form of moist soil is critical in the compaction process but a lot of soil problems are from swelling soils that were previously compacted properly because of poor drainage "swelling soils" I think thats what happened at the new runway in BKK.

[trubrit]

Something no one seems to have mentioned about raising land levels, flooding.When I purchased our land I noticed the gradient was down road towards us, which meant all the water would be going my way. So I raised the entire plot level by 1 mtr and the house foundation level by a further metre.After four almost continuous days and nights of rain the soi outside looks like this

IMG_3117.jpg

While the house is still high if not dry.

IMG_3122.jpg

[beer monkey]

Doing hairstyling now Val.(good bit of advertising..lol)

" Maison Val, The House That Hair Built ...Your Hair... Styled by Val ",... do you do wig-poms..?

[AussieBoy]

Aussie boy,

how about non-filled land that is primarily solid clay that is pretty much hard as rock.. We built our house on such a foundation with the T footed pillars put down about 1.75 meters.. It's been a year and I don't detect any settling cracks at all so would imagine that the land is quite solid enough for the depth of the footings..

The depth sounds right, but clay goes from hard as rock to sticky bog hole expansive clay with movement, depends on the type of clay, particle size will depend on the expansion, western world designs have various test to determind the shrink swell of a soil, and from there a footing can be designed, to minimise movement.

My own home Udon was hard as rock last december, had trouble just digging some small post holes, come April with plenty of rain, you would sink down a few inches, and could put your shovell down the full blade with out any trouble, very fine granular clay 0.1mm or less, drove a delivery truck on it loaded with 3 tons of material December, no problems, come wet season, can not even drive a car over the same spot with out sinking

In oz we tend to use raft type designs footings for the slabs to sit on, generally 600 deep x 400mm wide with reo on the perimiter, and at 3mt centers accross the slab.

Frazee seems to have done the correct thing with the footing design, typical Thai design, not used much here in the west, bored piers or raft slabs are more economical in the west, spreads the load better, but the Thai way works well, last used that T design footing in the late seventies.

Happy in Building