I have had to post a lot of questions on the forum on how we can fight the problem of our walls soaking and the paints comming off. Recently we had to inspect a house for sale which was built with prefabricated concrete walls.
My surprise was that the upper layer that was plastered was comming off as if it was having a water problem. Only one thing came to my mind and that was the fact that the cement mix might just be wrong., What do you think?

Replying to [eloho]:

Hi Eloho, good seeing you again! Please drop me a line via e-mail, if you have the time.

The problem you're describing is called "spalling" and the causes can be many. Sometimes it's enough to just scratch off the loose stuff and re-mortar the wall. But it could also be that these panels are of low quality and can't hold the weight of the roof.

So I would say have an architect or civil engineer have a look at it - one of those old grumps who want everything to be perfect. It could save you the headache of having to deal with the deaths of the future inhabitants of this house who might get crushed by the falling roof.

Replying to [eloho]:Hello, there is a possibility that what Germex suggested about poor quality, but usually if that is the case there would also be cracks and chunks of concrete comming off not just the plaster.

They build houses in Ecuador using cement and brick/blocks. Speaking with my wife´s cousins one whom is civil engineer and the other whom is an architect, they said the problems could be the following.

1) When the walls are built they put a thin coat of cement on the wall to smooth it out so they can finish it with the plaster. To put the cement on the wall they have to soak the wall and get it very wet so the wall doesn´t draw in the moisture from the cement causing it to dry too quickly and crumple off. Then they should let the walls dry for at least a weak to get all the moisture out of the walls. This doen´t always happen because the builders have a tight schedule and they come in and plaster too soon and a few weeks or months later the wall starts spalling.
2) The foundation, the roof ( if it is concrete ), or a wall backed up to the ground was not sealed with a tar membrain or sealed incorrectly and causing water to seep into the walls. The bad part of this is that concrete is like a sponge and absorbes water. It can absorbe the water in one place and seep through in another.
3) When the walls are built then they chisle out and install the plumbing and electrical systems. This is done before the thin coat of cement. It could be possible that there is a pipe leaking and causing the spalling. Again the water can be leaking in one place and show up in another.

You definetly need to have some professionals come in and find the root cause of the problem and not just treat the symtoms. This will prevent you from some major headaches in the future.Well I hope this helps.
Best regards,
David

Replying to [eloho]:

It is maybe the cement mix .i can not sure . But i hope that everything will goes on well with you !

God bless you ! My friend !

MSN : lilychina1982@hotmail.com

Replying to [eloho]:I have many times agreed with Mr. Germex. I have spent many years cleaning and fix concrete.
If you can find and consult the builder on his new job you will find what he mixes with his cement. The formulas for concrete are different in each country. The builders learn different tricks. Some tricks do not work in all climates.
If the Spalling is occurring on the first floor the moisture could be wicking up from the ground.
If the Spalling starts at the roof line you may have a faulty seal on the roof.
If the Spalling is random you may be chasing a contaminant in the morter used to tuck point. Too much Aluminum, Ash, Pumice???
Your answer is hidden on the new job site with the builder and the plumber.

Replying to [eloho]:A big thank you to all of you who have contributed to this discussion, I see a lot of sense in the reasons you have given. To my great friend Garmex, you always set the pace, I want to also commend the contribution of my friend dieselUSA from Ecuador, you were very educative and I believe everyone of us is having a great time, I am looking forward to more comments they are highly appreciated.

Replying to [eloho]:

Hi Eloho! Found this useful link and in page 2 you will see a bibliography of more useful articles that offer answers to your question and more. Hope it helps!

http://findarticles.com/p/articles/mi_m0NSX/is_5_48/ai_102749909

All the best,
macs2005

Replying to [eloho]: Thank you very much my dear friend for the link, I was there and had quite some handy information.