My Nanny/maid House Is Falling Over Again

[kurnell]

We built a small room at the back of our new house for the nanny to live in, with bathroom, space for a bed etc. approx 4 x 2.4m. It had been piled to a depth of about 9 metres and after 6 months it started to lean over, then 3 years down the track the walls were cracking and it was still moving. We asked another builder in to have a look and he suggested we knock it down and he would re-pile and this would solve the problem. It didn't, and now, 18 months later it is leaning over faster then it did before. A mate of mine suggested I should underpin it, but he said this is expensive. Does anyone know a reputable builder than can give me an informed opinion?

[lovelomsak]

I donot know a reputable builder but i would take what I would consider the easy way out.I would simply build on a large concrete slab. The larger the slab the better. I would reinforce it well with rebar.This would make a form of a floating base.

Sounds to me like the soil has no integrity and cannor aupport weigh over a small area. A large base will reduce the stress on the support form by shear distribution of effort. If you are really intent on making it work lay a base of gravel about one meter in depth for the area the base shall be built on. Pour a thick base of concrete and place jacks on the slab of concrete. Then build the a frame of steel to sit on the jacks.On this frame build the house. Keep the house level with the jacks.

[trogers]

We built a small room at the back of our new house for the nanny to live in, with bathroom, space for a bed etc. approx 4 x 2.4m. It had been piled to a depth of about 9 metres and after 6 months it started to lean over, then 3 years down the track the walls were cracking and it was still moving

The error in the present construction is the extension is resting on >20m deep piles of the existing main house at one edge and the other edge is resting on only 9m deep piles. Difference in settlement of the structure is the cause of 'lean over'.

The correct way to build is to have the extension built as a separate structure all resting on 9m deep piles. It will settle more than the main house, put will settle evenly and not lean over.

Edited October 18, 2012 by trogers

[Morakot]

I donot know a reputable builder but i would take what I would consider the easy way out.I would simply build on a large concrete slab. The larger the slab the better. I would reinforce it well with rebar.This would make a form of a floating base.

Sounds to me like the soil has no integrity and cannor aupport weigh over a small area. A large base will reduce the stress on the support form by shear distribution of effort. If you are really intent on making it work lay a base of gravel about one meter in depth for the area the base shall be built on. Pour a thick base of concrete and place jacks on the slab of concrete. Then build the a frame of steel to sit on the jacks.On this frame build the house. Keep the house level with the jacks.

I very much doubt that it will work. It might lean again or start to drift. The technical solution would be called: deep foundation, which transfers the load of the structure down through the upper weak layer of topsoil to the stronger layer of subsoil below. Yes as pointed out the foundation should be independent if it is for an independent structure. Alternately a ground improvement might work, prior to building a shallow foundation.

Edited October 18, 2012 by Morakot

[Morakot]

The correct way to build is to have the extension built as a separate structure all resting on 9m deep piles. It will settle more than the main house, put will settle evenly and not lean over.

I agree. What causes the leaning is probably an interference of both structures with their different settling rates.

[lovelomsak]

I donot know a reputable builder but i would take what I would consider the easy way out.I would simply build on a large concrete slab. The larger the slab the better. I would reinforce it well with rebar.This would make a form of a floating base.

Sounds to me like the soil has no integrity and cannor aupport weigh over a small area. A large base will reduce the stress on the support form by shear distribution of effort. If you are really intent on making it work lay a base of gravel about one meter in depth for the area the base shall be built on. Pour a thick base of concrete and place jacks on the slab of concrete. Then build the a frame of steel to sit on the jacks.On this frame build the house. Keep the house level with the jacks.

I very much doubt that it will work. It might lean again or start to drift. The technical solution would be called: deep foundation, which transfers the load of the structure down through the upper weak layer of topsoil to the stronger layer of subsoil below. Yes as pointed out the foundation should be independent if it is for an independent structure. Alternately a ground improvement might work, prior to building a shallow foundation.

I totally agree the deep foundation is the conventional wisdom on how to deal with this. But you have tried twice now and still havenot found the subsoil that will support this theory.The floater design is as good as the cement base you use to place the jacks. As long as the base doesnot break or seperate you can compensate for sinking and drift to an extent with the jacks unlike using deep foundations. It appears as though you are getting sinking no matter how you approach it. So I would look at alteratives to deep foundation and look for ways to correct sinking as it happens. Just my 2 cents worth. As the saying goes with free advice you get what you pay for.(should have been a smiley there but couldnot get it to work) Good luck none the less and hope it works out for you this time, with whatever you do.

[kurnell]

Cheers guys.

The building is on a concrete base and it is up against the house as we only have a small plot of land. Still looking for a solution.

[Khun Jean]

Make it very light.

Steel pillars/beams with something like smartwood as a cover/walls. Make that strong with a thin mesh/render on the inside.

Maybe put some isolation and have an inner wall of some lightweighrt material, maybe the thin concrete boards.

Edited October 18, 2012 by Khun Jean

[ignis]

Yes I agree with the above post, make it lighter with steel pillars.........

Myself looked around at all the lean to constructions, most had started to lean over in a short time, after time you see builder go to these places and fill in the crack and later the wide gap..later must go on the roof and add another tile or tin over the gap.

At the time I had the house built, I got the builders to fit a lean to roof and frame fitted on the back, with a steel frame,, The steel frame = 3 RSJ's bolted to the house pillars + RSJ bolted to the ring beam the full length, 3.4 meter from the house got then to drive pillions into the ground and then fit the 3 RSJ's uprights, making a steel frame with roof..

After they signed off on the house, myself filled in, 2 doors and 3 window, the walls I build with the white light thermo/conti block and skimmed with plaster..... Lean to 12 m X 3.3 m, kitchen 7m x 3.3,m that is over 8 years ago, nothing has moved, cracked or leaked.

The next house up in the Village also had the same size lean to built by the builders, but the normal way, around every 18 months get some builder to repair, feels very odd going into there kitchen as the floor slops away, they have a big opening into there kitchen from house, each repair job add more cement in the gap.. and that is on the floor, gap [filled in] at top between house and lean to is now over 40 cm !

As said before the correct way would be to have the lean to as free standing = Concrete pillars on all 4 corners and butted up to main house.

[trogers]

Cheers guys.

The building is on a concrete base and it is up against the house as we only have a small plot of land. Still looking for a solution.

I wonder if building regulations have been violated. Any house extension should still be at least 2m away from the property line if the wall has openings for windows, etc. This is to avoid spread of fire to adjoining properties.

A brick/block wall with no openings should be at least 0.5m from the property line.

Edited October 19, 2012 by trogers

[kurnell]

Cheers guys.

The building is on a concrete base and it is up against the house as we only have a small plot of land. Still looking for a solution.

I wonder if building regulations have been violated. Any house extension should still be at least 2m away from the property line if the wall has openings for windows, etc. This is to avoid spread of fire to adjoining properties.

A brick/block wall with no openings should be at least 0.5m from the property line.

Building regulations in Thailand?

[Khun Jean]

Building regulations are good for your own safety.

In Thailand it should be do NOT what others do.

[kurnell]

Building regulations are good for your own safety.

In Thailand it should be do NOT what others do.

The land around my house is 2 metres at its widest point. I can't build a nanny house anywhere else.

[Tanaka]

Building regulations are good for your own safety.

In Thailand it should be do NOT what others do.

The land around my house is 2 metres at its widest point. I can't build a nanny house anywhere else.

It sounds like you are in a mooban or some built up area so your house is indeed under building regulations that do exist here as has been mentioned. And it also sounds like you are in violation of said regulations which of course has nothing to do with the instability of the maid's illegal quarters. If your house had been solitary out in the sticks or at least over 200m from a main road, you could build whatever you wish.

[kurnell]

Building regulations are good for your own safety.

In Thailand it should be do NOT what others do.

The land around my house is 2 metres at its widest point. I can't build a nanny house anywhere else.

It sounds like you are in a mooban or some built up area so your house is indeed under building regulations that do exist here as has been mentioned. And it also sounds like you are in violation of said regulations which of course has nothing to do with the instability of the maid's illegal quarters. If your house had been solitary out in the sticks or at least over 200m from a main road, you could build whatever you wish.

50% of the houses on our mooban have additions to their house. One of them has built a 4 storey skyscraper on his, with no argument form neighbors or body corporate

[Sharp]

Suspended slab is the term u need to use .

Google it and u should find exactly what u need .

Sent from my iPad using ThaiVisa app

[Morakot]

Suspended slab is the term u need to use .

That could work. So you might end up with a level ground floor, but have walls, door and window frames, and the roof leaning like the tower of Pisa..

Edited October 22, 2012 by Morakot

[Khun Jean]

Building regulations are good for your own safety.

In Thailand it should be do NOT what others do.

The land around my house is 2 metres at its widest point. I can't build a nanny house anywhere else.

It sounds like you are in a mooban or some built up area so your house is indeed under building regulations that do exist here as has been mentioned. And it also sounds like you are in violation of said regulations which of course has nothing to do with the instability of the maid's illegal quarters. If your house had been solitary out in the sticks or at least over 200m from a main road, you could build whatever you wish.

50% of the houses on our mooban have additions to their house. One of them has built a 4 storey skyscraper on his, with no argument form neighbors or body corporate

And apparently no argument from you too.

Join the ones that don't care for anything. rules are for other people.

Sounds like a good plan.

[kurnell]

Building regulations are good for your own safety.

In Thailand it should be do NOT what others do.

What relevance to your perceived building regulations have to do with my question?

[Khun Jean]

Building regulations are good for your own safety.

In Thailand it should be do NOT what others do.

What relevance to your perceived building regulations have to do with my question?

The land around my house is 2 metres at its widest point. I can't build a nanny house anywhere else.

And again. Building regulations are for your own safety, or in this case the nanny.

They are also for others so that their property is not disturbed by others. This part seems to be not enforced in Thailand, so it leaves you with the first part, your own safety.

Edited October 22, 2012 by Khun Jean

[trogers]

Building regulations are good for your own safety.

In Thailand it should be do NOT what others do.

What relevance to your perceived building regulations have to do with my question?

In your case, the danger that the rear wall of your extension collapsing onto the adjoining property.

[kurnell]

Building regulations are good for your own safety.

In Thailand it should be do NOT what others do.

What relevance to your perceived building regulations have to do with my question?

The land around my house is 2 metres at its widest point. I can't build a nanny house anywhere else.

And again. Building regulations are for your own safety, or in this case the nanny.

They are also for others so that their property is not disturbed by others. This part seems to be not enforced in Thailand, so it leaves you with the first part, your own safety.

And how is that relevant to my question?

[kurnell]

Building regulations are good for your own safety.

In Thailand it should be do NOT what others do.

What relevance to your perceived building regulations have to do with my question?

In your case, the danger that the rear wall of your extension collapsing onto the adjoining property.

Who said it was collapsing?

[Khun Jean]

It is very relevant.

The right thing to do is not build an illegal extension and offer your nanny a safe place to stay.

[bbradsby]

The gent is requesting technical info, not editorializing.

To the OP, based on your posts:

1. Your site sounds like it has a pea soup stratum beneath the filled soil. I've seen a 9m pile driven into this stuff in just a few blows, and then another was daisy chained onto the first and another 9m pile driven down til proper resistance was met! Moral: every site is different.

2. With your two meters' working space, a proper pile driving rig hasn't the room to get in & set up in your alotted space... therefore the previous contractor likely did a 'cursory' pile installation with a portable rig or hand-knocked them down with predictable results. Did you actually SEE the piles driven, & measure them?

3. if the lean-to floor is sloping away from the house, the addition's slab is likely rebar-doweled to the house structure. Problem is, if you cut these dowels loose to make it an independent structure, there are not likely piles at the lean-to slab's corners nearest the house - thats why they doweled it in to the house, to save the trouble of piling next to the house.

Without seeing your existing conditions, I can't be sure of a design solution. But, I believe your best solution is likely a complete demo of your addition, full slab area excavation to a depth of a 50cm or so & removal of the exposed portion of the 'outboard' piles, create a flat compacted based with angular gravel on geofabric, and then pour a thick, highly-reinforced, floating 'raft' slab foundation with a lightweight, steel structure. It may settle differently from your house, but should stay relatively level, so create slip joint details at walls & roof.

...or, demo just the walls & roof, pour a leveling slab on the existing, rebuild with steel structure & slip joints - and hope the settlement stops or slows, but be prepared to repeat the process periodically.

Where is your house, btw?

[kurnell]

The gent is requesting technical info, not editorializing.

To the OP, based on your posts:

1. Your site sounds like it has a pea soup stratum beneath the filled soil. I've seen a 9m pile driven into this stuff in just a few blows, and then another was daisy chained onto the first and another 9m pile driven down til proper resistance was met! Moral: every site is different.

2. With your two meters' working space, a proper pile driving rig hasn't the room to get in & set up in your alotted space... therefore the previous contractor likely did a 'cursory' pile installation with a portable rig or hand-knocked them down with predictable results. Did you actually SEE the piles driven, & measure them?

3. if the lean-to floor is sloping away from the house, the addition's slab is likely rebar-doweled to the house structure. Problem is, if you cut these dowels loose to make it an independent structure, there are not likely piles at the lean-to slab's corners nearest the house - thats why they doweled it in to the house, to save the trouble of piling next to the house.

Without seeing your existing conditions, I can't be sure of a design solution. But, I believe your best solution is likely a complete demo of your addition, full slab area excavation to a depth of a 50cm or so & removal of the exposed portion of the 'outboard' piles, create a flat compacted based with angular gravel on geofabric, and then pour a thick, highly-reinforced, floating 'raft' slab foundation with a lightweight, steel structure. It may settle differently from your house, but should stay relatively level, so create slip joint details at walls & roof.

...or, demo just the walls & roof, pour a leveling slab on the existing, rebuild with steel structure & slip joints - and hope the settlement stops or slows, but be prepared to repeat the process periodically.

Where is your house, btw?

Apparently this is good advise according to my mate who is a quantity surveyor. The description is a little over my head, but I will consult the aforementioned QS for a translation.

The house is in Bangkapi in a noted flood area, though we are at least a meter above sea level as we were not flooded last year though the nearby Krungthep Kreetha was.

Point 2. yes I did see the piles going in and can confirm the length, hand knocked.

I don't think it was rebarred to the house.

Before i demolish the house I think I will give it another year or 2 to lean another inch before I spend another 100k

[trogers]

The gent is requesting technical info, not editorializing.

To the OP, based on your posts:

1. Your site sounds like it has a pea soup stratum beneath the filled soil. I've seen a 9m pile driven into this stuff in just a few blows, and then another was daisy chained onto the first and another 9m pile driven down til proper resistance was met! Moral: every site is different.

2. With your two meters' working space, a proper pile driving rig hasn't the room to get in & set up in your alotted space... therefore the previous contractor likely did a 'cursory' pile installation with a portable rig or hand-knocked them down with predictable results. Did you actually SEE the piles driven, & measure them?

3. if the lean-to floor is sloping away from the house, the addition's slab is likely rebar-doweled to the house structure. Problem is, if you cut these dowels loose to make it an independent structure, there are not likely piles at the lean-to slab's corners nearest the house - thats why they doweled it in to the house, to save the trouble of piling next to the house.

Without seeing your existing conditions, I can't be sure of a design solution. But, I believe your best solution is likely a complete demo of your addition, full slab area excavation to a depth of a 50cm or so & removal of the exposed portion of the 'outboard' piles, create a flat compacted based with angular gravel on geofabric, and then pour a thick, highly-reinforced, floating 'raft' slab foundation with a lightweight, steel structure. It may settle differently from your house, but should stay relatively level, so create slip joint details at walls & roof.

...or, demo just the walls & roof, pour a leveling slab on the existing, rebuild with steel structure & slip joints - and hope the settlement stops or slows, but be prepared to repeat the process periodically.

Where is your house, btw?

Apparently this is good advise according to my mate who is a quantity surveyor. The description is a little over my head, but I will consult the aforementioned QS for a translation.

The house is in Bangkapi in a noted flood area, though we are at least a meter above sea level as we were not flooded last year though the nearby Krungthep Kreetha was.

Point 2. yes I did see the piles going in and can confirm the length, hand knocked.

I don't think it was rebarred to the house.

Before i demolish the house I think I will give it another year or 2 to lean another inch before I spend another 100k

I doubt the raft foundation will work for 2 reasons: the first 50 cm is probably settled earthfill on original ricefield when they built up the site as a housing project, with soft water-logged soil layer below it. And second, a new row of 9m deep piles near the main house has to be installed, as a raft foundation resting only on an outer row of 9m deep piles will cause leaning towards the house.

Soil settlement can continue for over 10 years, with 70% occuring within the first 5 years. Bangkok soil can settle between 30-50cm over 10 years, depending on soil conditions and the load pressing on it. Thus, a 2m width can result in a slope of at least 1:7, like any typical ramp up a car park building. This is why I said there is a danger of collapsing wall.

[Crossy]

Right. Enough of the mud slinging please.

Several off topic posts removed.

Any more and holidays will be dispensed.