# How to fix this bad plaster patch? (Pics)



## HautingLu (May 24, 2009)

Hi,

I've noticed that there a couple of areas in this living room where there appear to be white patches within the plaster ceiling. I'm wondering if the previous owners used joint compound to patch a couple areas? Originally, I thought it might have been water damage, but it haven't noticed it getting any worse.

I picked at one of these with a putty knife, and it was very brittle and had an "ashy" feel to it. I'd like to fix this before painting the room.

What's the correct to fix it? Should I try to remove what I can and then patch it with Durabond? In the third image, there is a good like area that is like this.

Thanks.


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## Big Bob (Jul 27, 2007)

Great pictures A++.

ashy? could this also be described as caulky? soft to the touch?

if so, odds are this is old water damage. Roof leaks need to show up somewhere. 

4th pic looks like they used mortar or portland & sand rich (scratch coat plaster) to patch a hole?

Best fix: back cut to reverse 45* plaster a few inches past visable damaged area.. re-apply new plaster as required. Let this cure ( 30 days)
before painting.

Other quicker fixes are available... but may risk not being long term 100% successful.


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## HautingLu (May 24, 2009)

Big Bob said:


> Great pictures A++.
> 
> ashy? could this also be described as caulky? soft to the touch?
> 
> ...


You know I'm not actually sure what they used to originally patch it. I thought that was the original lathe and plaster, except they might have put some joint compound in certain areas.....like you said, possibly past/current water damage.

By ashy, I mean that it looked like it would crumble really easy. So when I hacked it a bit with the putty knife, it came off more in white powdery dust, not in chucks. 

What do you mean by "back cut reverse 45*" ? I need a translation to layman terms :yes: Would Durabond be an acceptable patching material? 

thanks.


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## AllanJ (Nov 24, 2007)

Back cut reverse -- As you cut away the loose plaster, angle the saw blade up
and away from the dead center of the hole. This way the hole, if it were to be
measured on the top surface of the ceiling material, measures slightly larger across
(perhaps by 1/4 to 1/2 inch) and the patch will be less likely to fall completely
out of the hole.


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## Big Bob (Jul 27, 2007)

AllanJ described the back cut reverse very nicely.. thank you AllanJ.

Fact is you really won't know what you will need to make the proper plaster repair until you chase the damaged plaster. What type of lathe do you have? Has the scratch coat been damaged?

Durabond makes a number of products, bonding primers & compounds for drywall and plaster. What you will need will depend on what you have.
Locate a good drywall / plaster supply house and take some samples from your demo and pictures with you.. some good counter help should be able to help you get what you will need.

again don't rush the painting if you restore with plaster (recommended)..
Cure time should not be ignored. If you rush it... the paint will never look right and you will turn your restoration into a patch job you will see forever.


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## HautingLu (May 24, 2009)

Thanks for pointing me in the right direction


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