Colored cement

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Colored cement

Postby Andaman Andy » Mon Feb 11, 2008 8:26 am

Hi,

Nearly finished my project, used colored cement (Earthcrete) in the bathrooms.
Having loads of problems with cracking, some cracking i can acept for a "rustic look" but some when i tap are hollow behind and i am afraid this will fall of in time, want to get this sorted before my last payment to the contractor.
Is this a case of they let it dry to quick? some of these cracks to weeks to appear.
The walls are just normal block work.
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Postby dozer » Mon Feb 11, 2008 8:52 am

Have seen many problems like this with pigment in render coat. Normally with a surface that will be painted, the prime and final coats are put on within a short time period. The first coat is applied, allowed to set up, and the final coat is then applied. In a situation with color render, the primary coats are allowed to fully dry. If the coats are not left 'rough' secondary coats will not stick.

I would not accept cracking as the rustic look. It looks nice but eventually over time it will start to peel off.
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Postby dozer » Mon Feb 11, 2008 9:11 am

Just to give you an idea of an extreme case here is a large project in central pattaya, which has small and large cracks throughout. In this section you can see the render coat beginning to 'fail' and soon it will be pealing off.
Attachments
IMG_2875a.jpg
rustic looking cracks or a sign of big problems to come?
IMG_2873a.jpg
trouble section colored render
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Postby Andaman Andy » Mon Feb 11, 2008 9:28 am

The undercoat looks rough.... so do you think this one has dried to quick?
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Postby dozer » Mon Feb 11, 2008 12:02 pm

Can you upload a picture?
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Postby dozer » Tue Feb 12, 2008 8:50 pm

There can be a number of reasons for small hairline cracks which develop in a render coat. Normally it is due to the skill of the person doing the render. There is a process they go through when rendering which involves sponging the surface with moisture. If this is done improperly it leads to hairline cracks.

Some sub par workers will render with cracks and cover it with paint which hides the cracks. Of course if you are rendering with color pigment in the cement, it becomes more critical that you have craftsmen who know what they are doing.
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Postby Andaman Andy » Wed Feb 13, 2008 5:22 pm

Dozer,

Think you are right..... further investigation has found that it is the render coat under the colored cement that has failed not the bond between the colored cement and render.
When we chipped it off it was dusty, we have decided that maybe the wall was not wet enough before the rendering and also we are wetting the colored cement after application to try and stop this happening.
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stucco

Postby cruzing » Thu Mar 13, 2008 10:01 pm

Andaman Andy wrote:The undercoat looks rough.... so do you think this one has dried to quick?



http://www.doityourself.com/stry/applyingstucco

http://www.unclebobstips.com/How_To_Stucco.asp

http://www.askthebuilder.com/696_Applying_Stucco.shtml

for repair: http://www.quikrete.com/ProductLines/StuccoCrackRepairTube.asp

The picture shows an application on a wood framed building so you have an extra step of tar paper over studs with chicken wire and a coat of plain stuco pushed into the chicken wire, then the scratch coat, skim coat and finish coat.

The last picture is the finished building. These steps are still the same whether interior or exterior, rough finish or smooth finish.

When we moved here, we knew what we needed to do, but because my husband spent so many years in the states, we hadn't a clue where to get everything we needed or even if it was available. So it was do the best we can with what we can get and improvise......and then find someone willing to learn the process. In just the last few years access to supplies is much better. Good Luck with your project.

Cruzing

P.S. this is a stucco project Mr. C did in San Diego.....several years ago now.
Attachments
scratch coat.jpg
skim coat.jpg
finish coat.jpg
finished building1.jpg
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Re: stucco

Postby thaifly » Fri Mar 14, 2008 12:08 pm

cruzing wrote:
Andaman Andy wrote:The undercoat looks rough.... so do you think this one has dried to quick?



http://www.doityourself.com/stry/applyingstucco

http://www.unclebobstips.com/How_To_Stucco.asp

http://www.askthebuilder.com/696_Applying_Stucco.shtml

for repair: http://www.quikrete.com/ProductLines/StuccoCrackRepairTube.asp

The picture shows an application on a wood framed building so you have an extra step of tar paper over studs with chicken wire and a coat of plain stuco pushed into the chicken wire, then the scratch coat, skim coat and finish coat.

The last picture is the finished building. These steps are still the same whether interior or exterior, rough finish or smooth finish.

When we moved here, we knew what we needed to do, but because my husband spent so many years in the states, we hadn't a clue where to get everything we needed or even if it was available. So it was do the best we can with what we can get and improvise......and then find someone willing to learn the process. In just the last few years access to supplies is much better. Good Luck with your project.

Cruzing

P.S. this is a stucco project Mr. C did in San Diego.....several years ago now.
gidday to the VERY KNOWLEGABLE CRUZING... wha t a nice job....appears hubby is enjoying himself ITS A GIDDAY TO ALL ITS THE THAIFLY FROM MAE RIM
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Postby Nawty » Fri Mar 14, 2008 2:17 pm

Anyone ever actually put the wire mehs over the entire wall surface to be rendered first ?

We do it over all the joints or cuts into blockwork for elecrtical or plumbing etc, but not the whole wall.

I have heard of it being done, but never seen it. One would think that this would/should stop any cacking at all....true ??
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