Hello all,

I couldn't get it sorted by searching through the internet. I was hoping i could post some pictures here to get a good answer. I am in a foreign country (Peru) where hiring an expert is not a real option. Better to get advise here and do it myself!

I am living on the seaside! Right at the ocean. The sea winds and oxidation are a big problem here. I have problems with my walls, but actually only inside. Which makes me think it is moisture related.

This first wall is inside, where a lot of breeze comes through. The old paint was completely coming off only at the bottom of the wall (the same problem as has started again now). We had taken the old paint off, treated with 'acido muriatico' (but didn't rinse the residu off, only brushed it off), painted first with a base paint that should protect against moist and 'salitre', then a 'sealer' ('sellador', a sort of shiny transparent layer that you apply with a sponge) and then an acrylic paint. The following is happening already after a month or two. Something is just bursting out of the wall!:



Another wall in a little storage room is much worse. The room smells like mould and it looks like there actually is a white kind of mould on the walls! This room has little to no breeze coming in.



I am pretty bummed about that first wall. I thought we had taken the right precautions with that anti-moisture paint and the sealer. I think both walls have the same problem? Both walls seem to be concrete.. Or at least the surface of it. They are very solid! What's happening here and how should i treat these walls to avoid this happening??

I appreciate the help!! Thanks so much!!

 

Rather than try to explain what it is you can just do a little research for the phenomenon know as "efflorescence".

Washing the walls with muriatic acid was fine but you should have also rinsed well with clean water.

Do you know how old the structure is as this is something more typical of newer concrete.

Go through the research on the efflorescence first and see if you can come to some meaningful information.

 

Is the peeling on the interior or exterior side of the walls? If this is the interior side, the wall probably needs to be waterproofed on the exterior.

 

oh wow.thanks!!. well we surely know what it is now.. on both walls.
ok.. have looked into it, but will need more time to sort that out!

- the walls are relatively new on the property, the newest!,but at least two years old. this could make the problem worse there than on other walls
- it are interior walls. the first wall is against the neighbours house which could mean a moist/wet condition on the other side. but, the second set of pictures (the really bad ones) is of walls that are open to the air on the other side
- i would think it is likely that the used sand for the cement is bad (a lot of salt) and the water used too not very clean
- we have ground water very close to the surface here. that could be a very likely source of moisture/water ('ground water penetration')
- for the first wall. we have not 'washed' the old efflorescence off.
- masonry could have been painted too early before fully cured/dried

the recommendations from the locals here to use muriatic acid, anti-moist/salitre base and the sealer was probably right! but we have not removed the old residue by 'washing' it off completely. also haven't washed off the muriatic acid residue. on top of that the cement could have much salt in it and ground water penetration.

any more suggestions? thanks so much!!

 

I suspected you probably had concrete made with sea sand. If that is the case and you also have a high water table I'm not sure you will ever be totally free of the problem.

One additional item is that you can add baking soda to your rinse water to help neutralize the muriatic acid.

 

ok. that's clear now. i guess i can only try to clean surfaces as good as possible, see how moisture can be avoided and use a good anti-moisture base and sealer. cheers everyone!