How to fix this wall?


  #1  
Old 02-05-21, 04:24 PM
B
Member
Thread Starter
Join Date: Sep 2014
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
How to fix this wall?

I have a basement hallway wall that suffered water damage many years ago.

I want to patch it up, but am a total beginner so I need some basic advice.

It looks to me like I've got a cement block wall, on top of which they applied a thin layer of either cement or plaster. Then they painted it. Is this right?

The odd thing is that the paint that has chipped off is so thick. As the photos show, it must be like 1/16" thick. Is that just paint, or is there something else going on here I don't understand?

So my guess to fix this --
1- Chip off all old paint
2- Apply new plaster to where it is missing
3- Sand it all down smooth to make a nice flat surface
4- Paint with primer
5- Paint with topcoat

Does this sound right? Thank you for your advice.












 
  #2  
Old 02-05-21, 04:59 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 26,394
Received 1,743 Upvotes on 1,567 Posts
Looks like veneer plaster. You have metal corners that have rusted out and are gone. Basically everything loose needs to be chipped off of the base layer (of either plaster or cement). You might possibly need to remove more metal corner, or at a minimum, prime it to cover up the rust. Cold galvanizing spray would be a good choice. After everything loose is all chipped off, i will usually brush or roll on a heavy coat of Gardz to seal the plaster. That way the mud you put on next will have a better chance of sticking.

I would probably start the repair by slathering on a layer of Durabond 90 as your first coat. Use a wide drywall knife, a couple inches bigger than photo 3 so that you can coat it all at once... (10" or 12"?) . Durabond is a powdered setting compound that you mix with water in a drywall pan... it does not sand easily, so try to lay on a very smooth coat.

Once that first coat cures you would put on a couple new corner beads. For repairs like that I like to go over the top with a metal reinforced paper corner bead. You use regular premixed joint compound thinned with a little bit of water and wipe a thin smooth layer on the entire corner, then firmly press the corner bead into it... then use a 3" knife to wipe the paper edges down tight to the wall. Put excess mud back into your drywall pan. Then let that dry.

For your following coats you can just use regular joint compound. It will probably take you 2 or 3 more thin coats to get the wall smooth. The biggest trick to finishing is to not put too much mud on the wall. Many thin coats are better than thick ones. There are plenty of youtube videos on drywall finishing that you can watch to learn. Easier to watch than for someone to try to explain how to do it. The smoother you can get it with thin skim coats, the less sanding you will have to do. No one likes sanding. So try to make every layer smoother than the last one.
 
  #3  
Old 02-05-21, 06:22 PM
T
Member
Join Date: Jul 2003
Location: California
Posts: 1,873
Received 41 Upvotes on 34 Posts
Is the thick coat that is flaking off brittle? Does it soften if you wet it? I think you have some kind of a plaster finish over a plaster basecoat. If it softens when you wet it it is joint compound. Not a good situation. I think that the abrupt cutoff at the edges looks more like plaster. The lines you see in it are from the notches in the darby, the tool the plasterer used to straighten the wall. The plaster could be gypsum plaster or it could be Portland cement plaster. It looks more like gypsum. Is there any moisture intrusion from outside the wall? If so the gypsum plaster has probably deteriorated. At a minimum scrape off everything that is loose then a little more. If you replace the corner beads as XSleeper suggests use vinyl. Do you know if the water damage was from a flood or from intrusion from outside? If you have ongoing water problems joint compound will just not hold up. Even Durabond will not last forever if it gets wet.
 
  #4  
Old 02-07-21, 10:31 AM
B
Member
Thread Starter
Join Date: Sep 2014
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thank you both for your advice.

More info: The house was built in 1950. The water problem is fixed, so no problem about that going forward.

Looking closer, I see that the paint chips are actually paint on top of 1/16" layer of some whitish-gray material.

It has the darby notches on it, just like the wall. So the idea of a plaster finish on top of a plaster base coat would seem to be it.

With the good advice here, I think I could probably fix where this stuff has chipped and fallen off the flat wall. But those corners and the area around the metal... maybe I should hire a pro for that.

Thanks again.

 
  #5  
Old 02-07-21, 10:43 AM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 26,394
Received 1,743 Upvotes on 1,567 Posts
You can lay the new corner bead on top of the old... It will just build it out a little farther and will mean you would need to coat those corners all the way to the ceiling.
 
  #6  
Old 02-07-21, 05:43 PM
T
Member
Join Date: Jul 2003
Location: California
Posts: 1,873
Received 41 Upvotes on 34 Posts
Your initial post pretty well describes how to fix the wall. If any of the base coat is loose or punky you should scrape it off too. Your best option for the fix is a setting type joint compound. Make sure you get of all that is loose of the plaster finish. Don't build anything you put on thicker than the edges of the existing. In fact keep those edges clean then on the last coat use ordinary joint compound to finish off everything nice and smooth and flat. This can be sanded to get it to suit you.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: