# Cracks in plaster walls



## Alkyd (Feb 14, 2006)

What is the best way to fix cracks and fractures in interior plaster walls? What is the best way to fix flaking paint on a plaster wall which is probably due to moisture? Thanks Robert


----------



## Miniroller (Sep 19, 2006)

Not quite sure if it's applicable to your problem, but i've seen these real good plaster guys use this elastometric stuff (was in a tube kinda like caulking) and then coat over it with lightweight compound. It worked awesome. The walls were ancient- horsehair plaster and the house was built around 1804. I was the lucky reciepient of a three layer wallpaper removal process there.


----------



## JNLP (Oct 21, 2006)

I usually just mix a little 45.


----------



## Danahy (Oct 17, 2006)

I open up the crack alittle. Cross crack it at the ends to stop the crack from growing. Push as much 45 into the crack as possible, and top coat with a light weight compound for the finish. Then oil prime as latex anything on plaster might frog eye or bubble, then paint with whatever you're using.


----------



## boman47k (Oct 13, 2006)

> I open up the crack alittle


Do you backcut or v notch it and brush the loose stuff out?



> Cross crack it at the ends to stop the crack from growing.


Interesting. But if it is stress crack, it matter?


----------



## Richard (May 21, 2006)

boman47k said:


> Do you backcut or v notch it and brush the loose stuff out?
> 
> 
> 
> Interesting. But if it is stress crack, it matter?


a v-notch works best and yes, always clean out the loose "stuff". Stress cracks cannot be fixed unless the house is completely done settling. They will come back, and come back, and come back forever--I have customers who have them and dont want me to even waste my time--

Just a tip when repairing plaster--Dont use premixed compound---Always use powder like 45. I'm doing a job right now with tons of plaster repair....45 is so incredibly easy to sand, so worth the mixing:thumbsup:


----------



## boman47k (Oct 13, 2006)

I ahve never used the powder. For what little rock/ repair I do, I am thinking of trying it because of the waiting for premix to dry.


----------



## Richard (May 21, 2006)

boman47k said:


> I ahve never used the powder. For what little rock/ repair I do, I am thinking of trying it because of the waiting for premix to dry.


Powder is easier to sand than premixed, dries faster, and is the recommended form when fixing plaster. 

Hell if you're looking for dry time, I came across an additive that you add to some 20---long story short, get ready to sand in 10 minutes:whistling no lie


----------



## boman47k (Oct 13, 2006)

> www.contractortalk.com/showthread.php?t=14867&goto=newpost


hehe, not sur eI want anything that quick. I don't know for small areas....


----------



## Frankawitz (Jun 17, 2006)

Stress cracks are because the house exspands and contracts every year, we have this here in Michigan, the way we fix these is to open cracks in v notch then we use Durabond 20 in brown bags, shave off then hit with topping, also we use paper tape not mesh since when the house goes to exspand the cracks don't show up for years. with mesh tape you end up with a crack with checker board look.


----------



## GoodPainter (Apr 23, 2006)

Who makes Durabond 20 ?

Where can I get this?

Robert


----------



## Richard (May 21, 2006)

GoodPainter said:


> Who makes Durabond 20 ?
> 
> Where can I get this?
> 
> Robert


Home depot or any other supply place should have it--20 kicks somewhat fast, just so you know


----------



## Chris G (May 17, 2006)

Sometimes I cut a groove. For hairline caracks I tape, and coat with sheetrock 20, 45 or 90. 

Also you can use these if it looks the plaster may be pulling off the lathe.


----------



## painterman (Feb 5, 2005)

Yes to all the above. Plaster washers are the best way to secure the loose plaster to the lathe. 

Stan


----------



## Riverside Paint (Sep 16, 2006)

*.*



Alkyd said:


> What is the best way to fix cracks and fractures in interior plaster walls? What is the best way to fix flaking paint on a plaster wall which is probably due to moisture? Thanks Robert


I run the cracks with my 5-in-1 to cut the loose stuff. Ive learned the hard way to be careful scraping plaster, especially when it's old. Those 1/16" wide cracks have a funny way of turning into craters when you least expect it. Mesh tape should be applied over all cracks, figure at least two coats of mud (maybe three) over the tape, one round of light sanding and youre good to go. Plaster weld, imo, is a must on and around problem areas. I always use straight joint compound. Mixing in a small amount of plaster of paris accelerates dry time. Zinsser cover stain is the only primer I use on plaster.


----------



## painter77 (Sep 22, 2005)

I use this product all the time [KrackKote] --a very good product.

I use it a bit differently from the manufacturer's instructions: I add a little water to the needed amount of KrackKote, mix well (the KrackKote paste is more brushable now), brush the mixture on the crack, place Tuffglass Fabric, brush on again. Let dry. Then apply a final coat or two of spackle (20 min or Ready-Patch). 

The product is a good time saver. Last month I did a 15'*20' 'historic' room that had so many cracks on its plaster ceiling or walls --length-wise, approx 300' of crack altogether. All the cracks were fixed, pernamently and nicely, in about 7 hrs. The costs for Krackkote were around $80.


----------



## Brushslingers (Jul 28, 2006)

I've used the same method for years... I vcut the crack then "seal" it with a clear shellac spray, from there it's easy to skim it with whatever you want. Plaster is funny, if you don't seal it with something it will always be powder.


----------



## Glasshousebltr (Feb 9, 2004)

Frankawitz said:


> Stress cracks are because the house exspands and contracts every year


Then Is it more profitable to sell on an expanding season?:whistling

_"I don't know what happened......the kids room was there last fall.":w00t:_

Bob


----------



## Frankawitz (Jun 17, 2006)

Stress cracks are there because the building moves every year, some cracks will show one year and the next year they might not show. but anytime we fix these we always use paper tape just because when the building moves these cracks will open up and if you use mesh tape the crack will be there with the mesh tape showing up cause the patch material crumbles and falls out, with the paper no way for it to fall apart. as for plaster turning to sand it's because the basecoat of sand portland cement and lime has lost it's bonding due to moisture or water which in turn washs out the salt in the cement, It's call Effloresce this will turn the plaster putty coat to a white powder of salt crystalls.


----------

