Patching and Plastering - Wallpaper/Plaster

I have recently peeled off the wallpaper (quite a few layers) in my dining el and kitchen. There were quite a few layers in both rooms. I noticed, particularly in the dining area that the lower portion of the walls (plaster) is thicker than the upper portion. Like they (the builders?) used joint compound or something to join the plaster and wallpaper. I would like to know how I go about evening out these sections. It looks like the builders layed the initial section of wallpaper, as the once hidden walls are much smoother than the area that has been exposed all these years. The house was built in 55. Does the entire wall have to be skim coated? If so, what kind of project is that? Can a novice do it? Any advice would be greatly appreciated.

Generally you will float the uneven portion out however far to make it unnoticable. To even out the roughness will require skim coating those areas. While skim coating may be a little intimidating it isn't all that hard to do. You can use joint compound or a setting compound. Actuall plaster work is beyond my expertise but our plaster pro should be along later.

Thank you for the response. My initial plan of action was going to be to sand it down as best I can, then try to float it out with some of the left over joint compound from my bathroom.

I guess this question will be for the plaster pro... was it common for builders to lay the wallpaper on the wall and then skim coat the exposed area? Like I said, the wall where the paper was feels much smoother.

How much is the offset?

At one time could there have been a wainscot?

I'm thinking that there was something on the lower part of the wall that was covered up with goop. It could have been to cover the holes where paneling was put up or tile or maybe for some reason that made sense at the time the wall was not finished and someone who was not a plasterer smoothed it out with goop.

marksr's advice on the fix is right on. Try it. You might have to do more sanding than a pro but you can do it. Remember, two or three thin coats are better than one heavy coat. It's alright to sand a little between coats to get the bad lines and humps out.

If it is at the right height, put up chair rail molding to hide the transition. It is common to have two different textures or colors above and below the chair rail.

I have seen rooms that were built with the intention of hanging wallpaper. The plaster guys or the sheet rock guys spend less time making the wall look pretty because they know that paper will be covering things up. In your case, it sounds like there used to be some sort of application to the bottom of the walls that has been removed.

Thanks for the replies. I will float it out and do some skim coating.
It never dawned on me that there may have been paneling or something there.
Chair rail molding was the first idea I had.... unfortunately the "seam" is too high. Oh well, nothing has been easy with this house, why would this be any different?? lol