The Walls Of Jericho - Thai Style.

[up2you2]

Within a year of my house being constructed various cracks started to appear in a specific wall / area, as if the foundation footing at this particular point was subsiding.

They appear above a first floor concrete beam - attached.

These cracks at the time were hacked out and re-plastered, with the consequence that two years later they have all re-appeared.

What's interesting to note that they seem to go vertically and horizontally, this in itself could imply something ?

I have some specific questions that I would be most grateful to be enlightened upon:

Removing all the plasterwork to expose large cracks in the brick work as some have suggested, that might be traced back to the concrete beam, might be totally academic in the event that the movement was coming from below this concrete beam itself. It's a huge risk and inconvenience to take due to the fact of what it might cost, how long it would take, and the potential damage that might be done to the wooden staircase.

Okay to put this another way, what are the odds that all these cracks have solely been made through faulty plasterwork ?

Solely hacking out and making good the present cracks is not an option in itself, as previously when this was done the whole house was covered in dust, as this wall is situated in an open stair well.

So from experience which is the best silicone solution, manufacturer and brand please, that might best provide some kind of temporary conclusion ?

[sometime]

By looking at your first picture I would investigate if you have a water leak either from water supply to the house or the outlet to septic tanks, this would cause the footing/pillars to raise and fall according to the amount of water going under the house.

If the builder did the usual with concrete rings for a septic tank, or a soak away too close to the house they could be leaking under the house.

Edited February 17, 2010 by sometime

[Riley'sLife]

I would think it is highly unlikely that the cracks you show are the result of faulty plasterwork. They appear to be settlement cracks caused by uneven settlement of the building. The only real solution to the problem is to identify the precise location of the uneven settlement and underpin as necessary. Major job.

Filler used to patch up in these circumstances will rarely be successful unless the settlement has now ceased, and will require constant attention no matter what quality the filler, so just experiment with one of your choice as you will have to re-do the job anyway in the future. I would use a cement filler rather than a silicone based product - Maybe applying a layer of fibreglass across some of the minor cracks and then skimming with dry-lining jointing compound would help, but the larger cracks can only be dealt with by hacking-off the plaster and re-applying, and this will also crack again until you deal with the source of the problem, or until the settlement ceases. Sorry to be so negative. If this was my home, I would do nothing other than monitor the cracks over the next few months to see if they are still expanding as it is possible that the settlement has now stopped,or will stop, if you are lucky. Hang a Thai wall hanging over the offending area if practicable and keep checking the cracks for a while.

[Riley'sLife]

The reason for the vertical and horizontal cracks looks like this is where the bricks/blocks underneath the plaster have parted company with the vertical concrete pillar and horizontal beam. All this is because of unsatisfactory groundworks.

[patong]

suspect subsidence, The first obvious sign of subsidence is the appearance of cracks. However, not all cracks indicate that there is a problem. Most buildings experience cracking at some time and there is no need to be alarmed by every crack that appears.

Cracks are not uncommon in new properties and newly built extensions. They are likely to be the result of the building settling under its own weight. These usually are nothing to worry about, nor are fine cracks that often appear in newly plastered walls as they dry out. Buildings shrink and swell naturally due to changes in temperature and humidity, which can lead to minor cracks where walls and ceilings meet. These too should not normally be anything to worry about.

What should be looked out for are small, usually diagonal, cracks which suddenly appear in plaster work inside and outside bricks at weak points, such as around doors and windows, especially after long periods of dry weather. These may, but not necessarily, indicate movement in the building´s foundations. The cracks will normally be thicker than a 10p coin, and usually be wider at the top. Doors and windows may also “stick” due to the distortion of the building.

Cracks more than 3mm wide are considered to be ‘serious’ and require immediate action, especially if they pass through brickwork or stone.

Edited February 19, 2010 by patong

[tutsiwarrior]

we bought 2 newly built shop houses in a small town then added a third. At the end of the erection of the third house the wife designed and built front and rear first floor terraces spanning all three houses. I said 'whooa, yer planning to build a steel raft plus concrete slabs plus concrete and tile finishing plus roof enclosure on top of what presently supports a small roof only...' as I was away at work she ignored me and went ahead...

this was 4 years ago...I have been monitoring small plaster cracks that have appeared near the beam joints but generally the project has been a success and we now have wonderful outdoor living areas where there never would have been nothing without the wife's initiative...

sometimes dem thais manage t'get things right...

[thairhone]

I worked with concrete for 28 years in the US, and I am here to tell you that if anyone at all knows anything about curing concrete here in LOS, they are keeping him/her locked away. I am building a house right now, and my wife's Uncle down the street is also in the midst of building. The morons he used had the forms off as soon as it set, piers and beams, both...usually the same day! They don't bother to wrap it or even spray it with water...they let it dry out, totally letting it dehydrate, so the chemical reaction, which needs HYDRATION, can not take place. Therefore you have very brittle, weak, prone to cracking, concrete. I used the used cement sacks to place on top of the ground beams that still had the side forms on, and soaked them and kept them wet all day long. I get up about midnight and respray to soak them again. Old used burlap corn sacks work well with this, although you do have to physically keep them wetted, as they will dry out. When they do take the forms off, I specify no sooner than 24 hours, longer is better.... I wrap the beam or pier in plastic and just forget about them for a week. This should be done for at least 4 to 7 days, while the initial reaction is taking place. As concrete cures, it produces heat, an exothermic reaction and will condensate, producing moisture on its own and if wrapped in plastic, it self bastes and keeps from drying out. This is a critical factor in getting the best result from concrete. Concrete cures for decades after the fact, if it gets a good start. If anyone is contemplating starting a house project, please keep in mind that you HAVE TO BE ON SITE...to make sure this gets done, and of course if you want it done right....you will have to do it yourself. Otherwise....forget it, as it will not be considered. I found some rather thin, probably 4 mil roll of plastic that was a little over 1 meter in width. The largest beam I am using is 40 cm deep and 20 cm wide, so they get a good wrap, with all sides being covered. Good luck to all. Ryp