cracks in Masonary walls

[irulandi]

i am constructing one hospital project at mumbai. In Masonary works we have used solid blocks, yesterdat i found in one wall is cracked in 5m lenght and width is 5to6mm.

That wall construction was over by before two months ( inculding plastering ) now POP applying activity in progress.

I found that crack from Masonary wall to POP.
Please give the details why the cracks is developing and what is the remady for this.
can i go ahed for painting in that wall?

 

[ishvaaag]

It may be on a number of reasons. Shrinkage, thermal elongation, differential settlement all can cause the cracks. The 2 first ones combined are the more likely cause of the cracks, and establishing construction joints close would have avoided that. Drying uses to produce cracks, and may be helped by heating in the roof causing differential expansion to crack the underlying walls. Reinforcing the masonry also helps to diminish cracks.

However, the stiffness of a tall wall is big, and if unreinforced differential support and then settlement may also cause cracks.

 

[sgwpe1]

Is the crack uniform in width or is top wider than bottom. Shrinkage would probably not be so serious as differential settlement. What can you say about the foundation on which the wall is constructed?

 

[SURYANARAYANA]

There are good chances that the masonry wall might have cracked due to differential settlement of the foundation beneath it.

There is also a chance that the cement used for masonry may contain a high content of free lime or magnesia, which inturn may cause cracks in the wall.

The solid cement blocks used may not be cured properly, or manufactured properly, i.e., it may be exposed to some alkalis/ chemicals during its manufacture itself.

Until full description of the structure is provided and a thorough investigation is carried out, the cause for the crack cannot be concluded accurately.

 

[engcomp]

Hi, irulandi

You say:
"In Masonary works we have used solid blocks, yesterdat i found in one wall is cracked in 5m lenght and width is 5to6mm.

That wall construction was over by before two months (inculding plastering) now POP applying activity in progress.

...can i go ahed for painting in that wall?"

1. 5 to 6 mm is one heck of a crack in a 5m wall.

2. I don't know what you mean by "POP".

3. No, don't paint the wall until you know the problem.

With a bit of good luck, the crack is caused by one isolated incident like shrinkage, permanent settlement, etc., in which case, fill it and forget about it.

With bad luck, it is caused by a reversible process. If you fill it, it will cause cracks elsewhere.

You must find the cause before you do anything.

Regards,

Helmut
engcomp@ozemail.com.au

http://www.engs-comp.com/

 

[irulandi]

dear again irulandi

now the cracks is enlarging , specifically its come staircase waist slab and near stair cases area.

i checked block the compressive strength test also passed.

now what i do .

please throw some light on this

 

[sgwpe1]

You say the problem is near the stairway. As I do not know the configuration of your construction, this is speculation, but it may be useful in identifying the cause of the cracks. Is the stairway supported by any portions of the walls. If so, that portion may be loaded heavier than other portions and so may be settling faster and farther.
Also, Irulandi, you have not yet answered my question: Is the crack wider at the top than at the bottom. Did you inspect construction of the wall foundation? What were the conditions? What is POP? Is the crack vertical or horizontal and is it zig-zag like it is following brick joints or is it straight. You need to provide some of this information for us to help you. If you provide this information, I think someone reading along can help you.
Scott

 

[swaminath]

Irulandi

Unless you provide clear details as listed in 'engcomp's
post' and 'sgwpe1's post' , we may not be able to help you.

Please give details about your construction , whether it is
a Reinforced concrete frame construction with block wall
infill ( or )
a load bearing wall type of a construction.

In case of a frame construction check for deformation of
the wall supporting beam.

In case of load bearing type of wall check for settlement
of the wall foundation.

In anycase , do not proceed with further work on the walls.
5 mm + cracks are positively dangerous , kindly take adequate precautionary & safety measures to avoid a possible
collapse of the wall.