Can I skim these walls?

[Rob S]

Hello!

I recently purchased a Victorian home that has plaster walls and I have very little experience with plaster. The house was wallpapered in every room so my wife and I removed all of it and would like to paint. The problem is that the walls look pretty rough, like concrete. I've attached some pictures below that will hopefully help.

There is also what seems to be a thin layer of white paint over all of the plaster. For the most part it's solid, but there are spots where the paint has peeled away and is flaking off at the edges. I've searched on this forum and I'm wondering of it's distemper which seems to be a nightmare. It is not chalky at all and does not come off easily. I think I would need to sand it off because it is stuck on so well except for the few areas where it has peeled away.

My questions are:

Can I scrape off the loose pieces of paint/ possible distemper, and then apply a few coats of PVA to the walls?
Would I need to scratch the walls up or is the rough texture enough of a key?
I was going to apply a very thin layer of joint compound over the walls for my skim and be done. Is there anything wrong with that? I'm not looking for anything perfect flat, just a smooth wall.

Thank you for your help!

 

[joe-90]

There's no reason you can't do what you say. I've done it loads of times.

 

[Rob S]

Thank you for your quick response! That's good to hear I'm on the right track.

So, I don't need to scratch up the wall? I don't really understand how keys work outside of the lath. It makes sense when the plaster mushrooms out the back behind the lath, but I don't understand how a scratch or indent does the same.

 

[joe-90]

It hardly makes any difference, but few trades people understand science. Basically, if you scratch the surface you make the surface area fractionally greater, hence more area to adhere to. It's such a stupidly small amount though that it makes no realistic difference.

 

[roy c]

I would never skim a wall without devilling it, It's the way I have always done it and I have seen plaster come off in sheets off a plain unscratched wall.. When you do exterior sand and cement work the first coat you put on is the "Scratch" coat so the next coat adheres to it...If your doing internal work same again scratch coat then float coat levelled up then devilled up with float and a few pins tapped in to top of float to give skim coat a key...