Inside corner plaster repair

Questions and answers relating to houses built in the 1800s and before.

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Inside corner plaster repair

Postby chooseopen on Wed Dec 14, 2011 4:43 pm

I have a crack on an inside corner of an outside wall (a gap really) that I need to repair. Some PO had filled the crack with caulk. I have chipped out all of the hard brittle caulk which has left me with a crack of about 3/8" wide. Its gets to about 1"' inch wide in a couple spots where the plaster had crumbled. The crack is about 1" deep when I insert a screwdriver and runs the entire 11' height of the wall.
Of note: When removing the wallpaper, I found evidence of minor surface mold which indicates to me that cold air is coming in through the crack causing condensation in the area.

How should I repair it? Simply putting up mesh tape with a couple layer of joint compound seems inadequate to me. Couple of ideas I had for filling the crack were: joint compound, caulk, or expanding foam



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Jason Elwell - Canton, IL
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Re: Inside corner plaster repair

Postby mfglickman on Wed Dec 14, 2011 5:27 pm

I don't know about historical correctness but tape and mud would do the trick. Assuming you're going to paint or otherwise treat the walls after removing the paper.

A 1" wide crack will be hard to fix with joint compound alone. And none of these materials will fix a cold wall, but you know that. :)
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Re: Inside corner plaster repair

Postby dalmatiangirl61 on Thu Dec 15, 2011 4:51 pm

I'd fill the crack with plaster, then mesh tape the corner, then skim coat the mesh.

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Re: Inside corner plaster repair

Postby plastrr385 on Sat Dec 17, 2011 5:01 pm

1 Pack durabond in the corner and let set
2 Use papertape in the corner and apply 3 coats of joint compound
3 Sand and paint


1 Brush out the loose plaster and bond
2 Fill with Lime and gauging
3 Smooth using paintbrush with water and putty knife as it sets

Hope this helps
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Re: Inside corner plaster repair

Postby Sombreuil_Mongrel on Sat Dec 17, 2011 10:19 pm

An alternative:
Foam the crack with spray foam insul., remove excess. Using Durabond, set a preformed metal inside corner, the kind with paper bonded to it. These are immensely strong compared to paper or mesh, and it's more moisture-excluding because of the foam insulation.
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