Painting horse hair plaster

[Beardog]

I am getting my condo ready for sale in the spring and have stripped the wallpaper in several rooms down to the horse hair plaster.  I have purchased some Behr BEHR MARQUEE Interior One-Coat paint that I plan to use.  A contractor told me he thought it would be fine if I used this directly on the walls without priming after the walls are patched.  There is a small amount of wall paper paste residue, but most of the wall is bare. 

My questions are:

• How hard do I have to work to remove every last bit of wall paper paste residue?
• Can I use the Behr combination paint/primer without a coat of primer first?

Thank you in advance for any advice you might offer.

[GuitarStv]

I've used Behr paint/primer before.  It works fine without primer, but you'll probably need two coats.  If you get the primer tinted the colour you're using it might be possible to get away with 1 coat cheap primer and 1 coat Behr paint/primer which is cheaper in the long run.

As far as painting over wall paper paste . . . don't do it.  Remove it all if possible.  Try sanding or soaking in water and scraping.  At best, painting over the paste will look very rough . . . at worst it will cause problems with the paint later down the road.

[Josiecat]

You need to wash the walls with TSP and warm water.  Then line the walls with wall liner.  Then paint.

[TomTX]

After prep, which is the most effort - I would first prime with Kilz, wait 48 hours,  then paint.

[Chester Allen Arthur]

I helped paint a friend's house which had wallpaper over horsehair plaster.  I'd get every bit of wallpaper residue off - any paste left will be noticeable after you paint.  As for painting, we did one coat of primer, then one coat of paint, and that worked great.  Horsehair plaster sort of drinks up paint, keep that in mind.

Also, consider using some spackle to fill in any large holes in the plaster.  Horsehair plaster is also prone to crumbling when you pull off wallpaper.

[Beardog]

Thank you, everyone, for all your suggestions.  There is definitely going to be some spackling to be done!  And some areas of wall paper paste that will need some extra attention.  There is one area that will need some dimples to tack down a lose area of plaster.  After those things are done, I'm hoping for some days that are warm enough to open a window a crack and paint.