# Method for patching plaster ceiling to drywall gap



## ClarenceBauer (Mar 4, 2005)

To repair the ceiling area you can use USG Structo-Lite plaster or Gold Bond Gypso-Lite these are both gypsum based base coat plaster. You should first apply a bonding agent to the existing area than apply a scratch coat after say 12 hrs. apply the ground coat leaving about 1/8 inch for your finish coat plaster.
For the finish coat you can use a mill mix plaster like USG Diamond Plaster or Gold Bond Kal-Coat finish plaster.
Dry wall joint compound over extended time will fail if applied over a plaster finish.
If you can not find or get the above products for the ceiling repair you can get by with using a setting compound like durabond you should still apply the bonding agent.


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## ClarenceBauer (Mar 4, 2005)

I just noted that this is a shower area DO NOT USE A JOINT COMPOUND IN THIS AREA.


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## oblvnnwtnjhn (Jul 15, 2018)

forgive my lack of knowledge in this area, by bonding agent, can you recommend a product? Thank you for your reply. 

After looking at this further, would it be beneficial to fill in the ceilling gaps with gypsum board, then perform the recommended procedures? 

Or can I use the bonding agent in the gaps, let the agent cure, then perform the plaster techniques with the recommended products?


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## ClarenceBauer (Mar 4, 2005)

There are many bonding agents available. Check the big box stores most if not all will have a bonding agent , a bonding agent for cement will also work.
I would not recommend the use of gypsum board for repair it that area.
Th original was most likely a Keene Cement plaster being it is a shower area & this product is not readily available in most areas of the USA. I would stick with a hard type gypsum base & finish. The previous products mentioned will last the longest in that wet area.


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## oblvnnwtnjhn (Jul 15, 2018)

ClarenceBauer said:


> There are many bonding agents available. Check the big box stores most if not all will have a bonding agent , a bonding agent for cement will also work.
> I would not recommend the use of gypsum board for repair it that area.
> Th original was most likely a Keene Cement plaster being it is a shower area & this product is not readily available in most areas of the USA. I would stick with a hard type gypsum base & finish. The previous products mentioned will last the longest in that wet area.


Something like this https://www.lowes.com/pd/Sika-32-fl-oz-Masonry-Bonding-Agent/999977074, brushed into the gap for the plaster products you mentioned above, to adhere to? 

Do I need to use tape to transition into drywall/plaster joint/corner or do I simply use the plaster products, feather & sand into a blend between the two?


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## ClarenceBauer (Mar 4, 2005)

Yes that bonding agent will be just fine. As for the wall ceiling joint normally the plaster ceiling & wall are not tied together due to the fact that they move at different rates. but being you will not be using a moulding yes you can use a tape use it in the second coat of base plaster do not use it under the finish coat plaster.


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## huesmann (Aug 18, 2011)

Ignorant question here, but why does he need a bonding agent when it seems to be the wire mesh should provide suitable purchase?


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## ClarenceBauer (Mar 4, 2005)

huesmann said:


> Ignorant question here, but why does he need a bonding agent when it seems to be the wire mesh should provide suitable purchase?


(1) is to keep the existing plaster from pulling the moisture out of the new plaster too quickly.
(2) Not all of the existing exposed lath is open for the new plaster to have a good mechanical key to attach & hold the new plaster.
(3) If the DIYer had all the working skills of plastering trade he could get by with NOT using a bonding agent but for the DIYer it is faster & simpler to use a bonding agent & it also work very well.


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## oblvnnwtnjhn (Jul 15, 2018)

ClarenceBauer said:


> (1) is to keep the existing plaster from pulling the moisture out of the new plaster too quickly.
> (2) Not all of the existing exposed lath is open for the new plaster to have a good mechanical key to attach & hold the new plaster.
> (3) If the DIYer had all the working skills of plastering trade he could get by with NOT using a bonding agent but for the DIYer it is faster & simpler to use a bonding agent & it also work very well.



Clarence is correct, not all the metal lathe is left. Which brings to question, would it be beneficial to cut some new metal lathe to mold into the bigger gapped area, still apply bonding agent, then proceed with base plaster/Structo-Lite? 

To confirm, 

1. I brush bonding agent into the wide gaps, let it cure 12hrs. 
2. 1st coat of Structo-Lite base, then tape joints, 2nd coat of Structo-Lite, let it cure, 
3. Followed by Diamond Vaneer top coat, sand/feather in the joints to match drywall/plaster ceiling joint?

Can I also use both or one of these products to make plaster mud to repair my swirl ceilings in other areas of my home? I have a few spots someone made an attempt but went with compound, applied too lightly. 

What brush/tool and technique were commonly used to create the swirl patterns?


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## ClarenceBauer (Mar 4, 2005)

Has the ceiling been painted ?
If not you can use the Diamond plaster finish you may want to add just a little bonding agent to the finish plaster mix DON'T over do it when add the bonding agent. Ads for the tool to make the swirls check the radius and see if it comes close to the size of a wall paper brush if so that put a pivot pin in one end & use it to make the circles or half circles. I hate to tell you this but If the ceiling has been painted you will have to use a joint compound.
The other very good method to plaster over paint is use a veneer plaster that STATES no bonding agent required if used over a painted surface this type product will cost a lot more than the plaster products available locally.
Yes you did the scratch coat , tape & brown coat correct.


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## oblvnnwtnjhn (Jul 15, 2018)

ClarenceBauer said:


> Has the ceiling been painted ?
> If not you can use the Diamond plaster finish you may want to add just a little bonding agent to the finish plaster mix DON'T over do it when add the bonding agent. Ads for the tool to make the swirls check the radius and see if it comes close to the size of a wall paper brush if so that put a pivot pin in one end & use it to make the circles or half circles. I hate to tell you this but If the ceiling has been painted you will have to use a joint compound.
> The other very good method to plaster over paint is use a veneer plaster that STATES no bonding agent required if used over a painted surface this type product will cost a lot more than the plaster products available locally.
> Yes you did the scratch coat , tape & brown coat correct.


The attached picture above was for reference, and a good area of the original swirl located in the living room. There are a few areas with half attempts of creating the swirl that I'd like to sand down, start fresh with good plaster, tools and technique to make it match the rest of the house. 

I have attached a patch spot from a previous roof leak above back door, and what appears to be a previous leak in the bedroom that may have been patched with drywall. I'd like to smooth, seal and recreate the swirls to blend it back in. 

I've also included a picture of the bedroom wall, odd we never noticed this stain but I put a moisture meter on it, we had heavy rains the past few weeks. The meter did not detect presence of moisture. A contractor friend suggested it's old stain that bleed through the cheap contractor grade flat wall paint. That is plausible. But the bubbles look new to me, but again, no moisture detected. I went to the attic, did not see any leaks or moisture.


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## ClarenceBauer (Mar 4, 2005)

If I was doing that ceiling repair for a customer I would use the Master of Plaster restoration plaster it can be used over existing painted plaster , Dry wall & joint compound it is applied in very thin coats is very user friendly can be textured or applied very smooth & can be colored for a molded finish. No sanding is required with this product.


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## oblvnnwtnjhn (Jul 15, 2018)

ClarenceBauer said:


> If I was doing that ceiling repair for a customer I would use the Master of Plaster restoration plaster it can be used over existing painted plaster , Dry wall & joint compound it is applied in very thin coats is very user friendly can be textured or applied very smooth & can be colored for a molded finish. No sanding is required with this product.


 Hank, I talked with Lauren at MOP awhile back, she said hi. 

Ok, finally found time to get started back on this last part of the bathroom renovation. I applied bonding agent and let it cure as you said, this is one application of Structo-Lite. Unsure if I need to apply plaster tape with a second coat of Structo-Lite or smooth this out, then apply Diamond Finishing Plaster and paint. The acoustic ceiling tiles we're installing are 1/4 thick, so it's not terribly imperative that I get it perfect, but cleaned up enough where drywall transitions into the plaster patching which will be painted the same color.


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## oblvnnwtnjhn (Jul 15, 2018)




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## ClarenceBauer (Mar 4, 2005)

You can smooth it out & than apply the Diamond Finish Plaster I don't think a tape under the finish is required.


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