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Nathalie
Cracked Plaster Wall

I recently purchased a 1902 Craftsman fixer upper and today as I was looking over one of the Living Room walls I noticed one corner was sealed with packing tape and then painted over. After ripping off the tape it revealed a fairly large crack where the two walls join.
The foundation and structure has already been inspected and the walls and floors in this room are sturdy and level.
So how would this crack have gotten here over the years? It almost looks as if someone actually scrapped it out themselves.
What would the best method of repairing it be?
The walls are textured so I'm worried that a typical mud or sealer won't adhere thoroughly like it would on a smooth surface.

Oldsckool
Re: Cracked Plaster Wall

My suggestion would be to further clean out the
crack and lightly sand out an inch or two past
on each wall. I would then lay down some mesh and replaster.

dj1
Re: Cracked Plaster Wall

It's good to have the pictures.

From the pictures, it doesn't look an unusual crack to fill. Fill it like you would fill other cracks, as described above. Then texture it to match the rest of the walls, prime and paint.

Oldsckool
Re: Cracked Plaster Wall

A trick that I learned on my first home remodel when
repairing corners, which present different challenges,
is to use an icing bag and an appropriate nozzle. Try
one with a bevel. An icing bag, like cake decorators use, allows
even pressure whilst the tip allows you to get it into
the crack. Might sound corny but it works great once you get the
hang of it.

Nathalie
Re: Cracked Plaster Wall

Is this how old plaster wall corners would have looked back in the day before they were finished? I'm curious as to what the plaster applier would have done to a corner like this.

Sombreuil_mongrel
Re: Cracked Plaster Wall

The original plasterer did not have access to expanded wire lath. When it became available it was universally adopted because it prevented what you have there. The wire lath reinforces the inherently weak 90 degree joints. Plaster by itself is very low tensile strength.
I would fill the corner with expanding foam, and mud/tape it with a preformed inside corner (metal with paper fused to it) not corner bead!
Casey

Oldsckool
Re: Cracked Plaster Wall

I would have to say it's nothing more than damage done from the house settling which is completely unavoidable. The repair job is particularly shoddy though. The key is to take your time and be thorough, don't be surprised if it takes you a lot longer than you think. Use mesh and put your compound/plaster on thinly, easier to sand and work with.

Nathalie
Re: Cracked Plaster Wall

Could I use a piece of Quarter Round for the time being just to cover the gap and keep out drafts?
I'm fixing up the windows in this room right now and didn't plan on getting to the walls until it was a little cooler outside.

dj1
Re: Cracked Plaster Wall

Temporarily you can put anything you like to stop the draft, including a quarter panel.

Nestor
Re: Cracked Plaster Wall

As a temporary measure, you could even put painter's masking tape over that corner and paint it pink.

If I was fixing that corner, I would:

1. Scratch out any loose plaster with a hook blade utility knife.

2. Paint white wood glue (mixed with enough water to make it into a paintable consistancy) onto both sides of the joint that I wanted my base coat plaster to stick to.
3. Mix up some base coat plaster like Domtar's Perlite Admix Hardwall (my favourite) or USG's Structolite. I'd mix that base coat plaster up with plenty of white wood glue in the mix water so that the plaster stuck well and dried really hard and strong.
4. Mix up some drywall joint compound (I use a powdered joint compound) with plenty of white wood glue in that too, and spread that on each side of the corner, and then press in a Trim-Tex vinyl inside corner bead:

and cover the legs of that bead with that same sticky mud. I'd probably do that in two pieces just so the mud didn't have time to skin over so it'd stick to the vinyl well.
5. Then I'd use normal joint compound to finish the corner, sand smooth, prime and paint. (By normal, I mean without any added glue.)

(On another board I used to post on, people were surprised that I added white wood glue to make my base coat plaster and joint compound dry harder and stronger, and I was surprised that they didn't do that. I've been doing that for well over 20 years, and it works very well. I highly recommend it.)

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