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-   -   Wet Concrete Walls: Painting apartments in China (http://www.diychatroom.com/f4/wet-concrete-walls-painting-apartments-china-59150/)

szstevo 12-13-2009 02:43 AM

Wet Concrete Walls: Painting apartments in China
 
Hello:

New member, first post.

I recently purchased an apartment in China. The DIY scene is small and the language barrier is something of a problem.

A common problem with apartments in China is wet spots showing thru the plaster, at the baseboard level (up to 6 to 12 inches up from the floor). Every apartment I have lived in has had a spot or two like this on various walls. The paint is bubbling and flaking off.

My new apartment is also afflicted. The walls are concrete covered with plaster. I can't seem to find information from my reading of various sites and forums.

I am guess the underlying concrete in these spots is wet and affecting the paint. There are no water pipes to be causing leaks. I scraped through the paint and plaster in one area today - the concrete did feel cold and damp.

What is my best course of action? I want to repaint, but would you like to fix this problem first.

Any ideas you can provide are appreciated.

user1007 12-13-2009 03:08 AM

You might have an oil based paint over all this? Concrete and oil based paints have never been able to get along well together. Chemistry thing. And same related concern, do you know if the composition of the plaster? You are probably going to have to try to seal the walls with something. Can you tell us what you might have available to you?

szstevo 12-13-2009 03:33 AM

sdsester: Thanks for your reply. Dulux seems to be the main brand in China. I haven't seen any other big brands.

As I said this is only a problem on the bottom of some walls. One wall has a 1 ft. patch, another an area about 2 feet long.

user1007 12-13-2009 03:59 AM

Quote:

Originally Posted by szstevo (Post 365841)
sdsester: Thanks for your reply. Dulux seems to be the main brand in China. I haven't seen any other big brands.

As I said this is only a problem on the bottom of some walls. One wall has a 1 ft. patch, another an area about 2 feet long.

Can you post a picture or two. It is hard to visualize your situation.

Are you groundfloor? Moisture may be "wicking" up.

And your issue is the paint peeling right? There is no obvious plaster failure?

szstevo 12-13-2009 05:13 AM

Photo here:

http://www.flickr.com/photos/stevosz/4180487255/


This is a really bad example from my current rental apartment.

As for plaster failure - the plaster easily comes away from the concrete in the affected areas.

Thanks for all your help.

user1007 12-13-2009 05:52 AM

Quote:

Originally Posted by szstevo (Post 365844)
Photo here:

http://www.flickr.com/photos/stevosz/4180487255/


This is a really bad example from my current rental apartment.

As for plaster failure - the plaster easily comes away from the concrete in the affected areas.

Thanks for all your help.

Cannot tell for sure but moisture is seeping most certainly into the plaster and I would guess the concrete remains wet too. If you can, you need to address all of this before you even consider spending money on paint.

You're probably going to have to demolish the plaster to at least the point you see no water seeping damage. Then you need to source the water damage and fix that.

Are you on a ground floor and does your building have gutters or any other system to divert water?

chrisn 12-13-2009 05:58 AM

It seems like there is water coming through the concrete from the outside. This problem should have been addressed when contruction was being done. It is possible that a product like Drylock would work IF you can get the interior concrete free of paint and get it dry somehow,maybe.

http://www.ugl.com/drylokMasonry/mas...ofer/latex.php

The oil product really,really stinks:yes:

szstevo 12-13-2009 06:08 AM

Thanks for your replies.

The unit is on the second floor or a 7 floor walk-up. I don't think there are water pipes in the wall (water is piped up the outside wall of the building).

There are two place this takes place - the interior of a wall that faces the outside stairwell and and an interior wall.

I had planned on removing the plaster and trying to dry it out. Any tips on that?

Thanks again.

user1007 12-13-2009 08:22 AM

Everybody has their methods for plaster demo. I like poking around with a fave old steel framing and fencing hammer with about a 1"D head on it. With a one inch hole I can usually get my finger in and tell how bad the situation is and how separated the plaster has become. Once I know what I am taking down I have been known to take bigger things to the project. It's great therapy but be warned. You have to get rid of it all somehow. Plaster is heavy stuff and people notice you dragging the contractor bags or filling a dumpster. Maybe not in China?

And not once, ever, in decades have I started with a plaster separation situation where I ended up not having to demolish a lot more than I expected so be prepared.

Reapplying plaster is not for the faint of heart either. I consider myself marginal to exceptional at blending minor repairs up to about 6sf but would never take on a major wall or ceiling.

itakitez 01-03-2010 11:04 PM

Hey there, Im also suffering the same issue over the straights in Taiwan.

I have learned that the local trick is to mix a cup of PVA (white 'school') glue into the tin of paint and this 'seals' the paint onto the concrete

However, before doing this I want to make sure Im not damaging the house.

I can surmise that the paint peeling is basically caused by two factors

1. Very high humidity, so inside air getting under the paint (this problem is 100x worse when noone has been in the property to run a/c or dehumidifiers)

2. After heavy continual rain (we had 3 weeks solid rain in November so the outer walls were in constant contact and eventually rainwater seeped through the concrete)

3. There may be a leak caused by water pooling up against the wall (for example a large load bearing beam protruding past an interior 'hung' wall) and slowly perculating through, an issue I have in 2 parts of the house caused by substandard architect and poor drainage - these will be solved by bringing these two spaces into the house and stopping their exposure to external elements.

My question is, if I use the PVA+paint option so effectively sealing the inside wall is this gonna damage the wall? Small amounts of water will pass from the outside through the wall and be blocked at the paint layer, but then as the seasons change, the concrete dries out and this water will go away - is this acceptable for concrete?

I have no idea about this material so Im a little lost and at the same time dont want to pay a local to do a botch job!


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