im living in a 26 years old double storeys detached house, from the photos i uploaded you can see cracks, concrete fall-off, thick scale corrosion of the metal support rods.

what could be the factors contributing to all these? how serious is this?

it obviously posing threats of concrete failures as a worst case scenario and decrease in resale values, but i need to know if a repair to the specific affected areas would be sufficient in reconditioning this? or a reconstruction required?

any experts here could provide me advices? most importantly the basic cost for the repair or reconstruction.

heres the photos:

(1.)


1st floor master bedroom primary frame, crack length 4m.
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(2.)

1st floor, crack beside window pane, length 0.5m
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(3.)

1st floor bathroom primary frame, crack length 1m
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(4.)

1st floor balcony underneath, cracks at frame and floor concrete.




1st floor balcony underneath, > 1 sqft of concrete dislodge, thick corrosion scaling developed on reinforcements.
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(5.)


ground floor concrete reinforced stud, >2 sqft of concrete dislodge, thick corrosion scaling developed on reinforcements.

From the picture of corroded steel bar,water sip into the concrete making steel reinforced bar corroded, once steel corroded, it expand and crack the cement from inside out, this is a serious issue.

Main root of cause, porous cement.

For 1 picture, land compacting/sink could cause similar problem as well, whereby you beam got pilling, so sink little but your wall is just sitting on non-pilling floor, sink more, so crack of the wall appeared.

Just my shallow knowledge in it. Feel free to correct me if I am wrong. I am not civil/building engineer.

thanks for ur input cherroy. i do speculate water/moist as the main culprit, but land sink, im skeptical abt it.... i guess i hav to pay a visit to the neighbours house.

any advice on the repairs/reconstruct?

i dun think patch-ups is the solution especially for those sustaining corrosion... i do not hope it has to be reconstructed, as in to demolished n rebuilt as it would cost bombs.... hope thrs alternative ways

This post has been edited by hAnn: Jul 25 2009, 02:58 PM

Further seeing it, there are some large 'stone' in the concrete exposing piece by piece.

Sorry I am not civil engineer, don't know it is norm to see cement peering off then exposed the stone or can see the stone one by one with so many in the last picture.

No worry my friend. Just buy some cement and patchup the crack like what they did on LDP. The chief engineer say its safe.

Seriously, the rebar is so corodded di. Once rebar failed, changes of collapse is very high. Moved out not safe to stay di. What's ur address?? i ll ask police to cordoned off this ill fated building.

This post has been edited by romba: Jul 25 2009, 03:06 PM

hmm... i do seen constructors adding sands n stones into cements to construct the pilings, not too sure abt this

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Added on July 25, 2009, 3:09 pm looking into the pockets

This post has been edited by hAnn: Jul 25 2009, 03:09 PM

There surely got stone and sand in the concrete if not it is not called concrete anymore, but seeing the stone piece by piece exposed like that is kinda not normal. I could be wrong.

Yes, the most important issue is the steel reinforeced bar corrode, it is the main load carrier. Corroded steel bar mean lesser diameter to carry load while if the corrossion penentrate into deep area of the diameter, then it cannot properly stand the load.

I'm not a civil engineer

As far as my knowledge

Concrete + steel = best marriage (due to same elasticity properties)

Concrete + steel + Rocks??? = Disaster????

There are many types of rocks with different kind of stress co-efficient.

thr r alot of water mark in the crack+corrode place so i kinda agree wit cherroy theory of porous cement. for the land sinking thr oso hav tis possibility... TS can u take some picture on ur house area, n oso include pict of ur house longkang