how should I prime my old walls?

Question

We're in the process of stripping the old wallpaper from our walls. Once all the paper is off we're down to the plaster. This house was built in the late 1940's so the plaster is probably about that old.

We've read online about how to prime new plaster walls but we're wondering what the best thing to do here is. We intend to paint directly on to the plaster (after priming).

Do we use a pvc / water mix? Some people suggest avoiding this due to getting drips of hard PVC...does the wall need priming at all?

Here's a photo of what we're dealing with (high resolution here):

Suggestions welcome!

Answer 1

Unless you have a remarkably uneventful time removing wallpaper you are often left with a surface less than ideally flat and having a mixture of different sorts of detailed surface types (stubborn last bit of paper, bare plaster, glue, old paint etc.)

You may want to consider a skim coat of drywall compound over the whole wall to remove minor irregularities and to provide a consistent base for the paint. In most cases it will be obvious if this is more or less sensible than a primer/sealer coat of paint if you have the idea of both in mind and look at where your walls end up when you get the paper off.

Answer 2

In the end we called a plasterer and got it re-skimmed due to the surface being very poor (lots of the plaster came off in the paper removal process).

Thanks for everyone's help, maybe it will help future DIY'ers.

Answer 3

Painting new plaster is much different than painting old plaster, mainly because of the chemical reactions in setting plaster and the long time-frames it can take to completely cure. 70 year old plaster is much easier to deal with, although you are going to want to prime it. I use Kilz latex (not a brand recommendation - other manufacturers make a comparable product), but any high quality primer should be fine. Drywall PVA sealers aren't necessary on plaster unless you use drywall mud or spackling to make repairs because plaster is much more water resistant on its own. If you patched with something like that, let them completely dry and just spot coat with PVA sealer.