Cracked plaster, cheesecloth, paint - how to patch.

[Spiper]

New topic on the same problem - what you see in the pictures is an upstairs bathroom wall in a 100 year old house. The plaster has cracked from the top corner of the window frame, up towards the ceiling. It appears as if this crack was patched some time ago, but about a year ago the paint started to crack and flake, exposing the crack. Not sure why this happened (or is happening) - there's no visible damage on the outside of the house or in the attic above.

I haven't repaired a plaster wall before, or encountered this cheesecloth-like fabric between the paint and the wall. So my questions are - how to repair this crack (or am I in over my head and do I call an expert), and then how to patch up the area including the wall and the ceiling (also has a fabric layer) without redoing the whole thing (or do I have to).

Thanks, people who know.

 

[PJB12]

Sometimes, Spiper, cloth was used in an attempt to reinforce a plaster repair. Decades ago, I worked for a plasterer and remember using it, but never that large. Maybe (just a guess) the fabric was pressed into a scratch coat instead of using hair entrained. This is a complete guess on my part.

Could it be old wallpaper? Our 125+ year old house had lots of wall coverings that were cloth backed and eventually painted over.

For the repair, I'd take a church key type can & bottle opener and drag it down the crack to widen it. Then I'd use the edge of the pointed end of the opener to back-cut the sides to form an inverted vee shape. Next clean the dust out of the crack.

Instead of buying scratch coat and finish coat plaster and having lots of left over, I'd most likely use setting type drywall compound and paper tape to fill and cover the crack. (Certainly I'd not use pre-mixed compound nor would I use mesh tape.) You can buy the compound in various working times- 5 Minutes, 15 Minutes, 20, 45, 60 and 90. Proform Quickset Lite is my favorite. Durabond is a bit stronger, but very hard to sand if you goof.

Fill the crack with the "mud", going wide an inch or so on each side. Embed the paper tape with your taping trowel or taping knife. When the coat dries at least until stiff, apply another, wider coat over the tape. Then, sand lightly and keep coating wider until you are satisfied.

I believe the setting mud and paper tape will provide a permanent repair that you can be proud of!

Paul

 

[Spiper]

Thank you, PJB12, for this lovely informative answer. Much appreciated.

 

[PJB12]

Thank you, PJB12, for this lovely informative answer. Much appreciated.

You're very welcome, Spiper!
Be sure to let us know how the repair goes and post pictures. I'll bet it turns out great!
Paul
PS: When you prime your repair & the rest of the room, I respectfully suggest using a good bonding type primer.
I enjoy using PPG Seal Grip Gripper. It bonds tenaciously and will do a great job of sealing in the new joint compound and any left over adhesives from the old wall. The final paint will cover quite evenly- even light pastel colors.

PPS: If you choose PPG, it's about half the price at a PPG store versus at Home Depot.