How can I remove or cover flooring adhesive on my walls?

Question

Background: I bought my first home recently from an elderly couple who had owned their home since 1970. The husband was a flooring contractor. In addition to installing different flooring in each of the ~12 rooms in the house, he sometimes also installed linoleum flooring on the walls. I want to remove the linoleum and paint the walls so they look normal.

After many hours using a hammer, scraper and occasionally a heat gun, I've removed the linoleum from the walls in two rooms. Now I'm receiving conflicting advice on what to do. The walls are in most places covered uniformly with a layer of glue. A handyman I work with says that we can cover it with drywall mud, sand it and then paint over it. My uncle who is an architect says I need to remove the glue first to make sure the drywall mud bonds to the wall. I know nothing about any of this. Do I actually need to remove all of the glue? If so, how do I do that? I tried using a sander, googone+wire brush, and a metal scraper. None of these worked well. I could use the heat gun to melt small portions of the wall and remove but it would take a really long time. If it helps, the walls are plaster.

Here are some pictures of the rooms. In some areas, you'll see that glue is chipping. In most areas, it is uniformly on there and will not come down without melting it or sanding it away or something.

Please do feel free to talk to me like I'm a five year old in the answers. I am new to home improvement and have no idea what I'm doing :)

Answer 1

OH MY!

With that much glue on the walls there only 2 logical options.

1. Cover with drywall compound, sand and give a light texture like orange peel. (You will work like crazy to get it perfectly smooth, so a light texture will hide the imperfection. The drywall compound does stick to the glue. I have covered walls just as yours with this method.)

2. Tear out all the drywall and re-drywall, tape and mud the room.

If you try to remove all the glue, you will spend hours of exhausting time and still have gouges in the walls that will need repairs that then may need to be textured anyway. IMO, I would cover with compound, sand and texture.

Answer 2

I've dealt with the same situation where commercial wallpaper adhesive was the problem. A skim was the best solution since you can't really grind away at drywall without doing damage.

1. Scrape away any loose material and high bumps with a taping knife or similar.
2. If there's a lot of fuzzy paper or you have concerns about the bond of joint compound, apply a coat of sealing primer.
3. Skim, skim, skim. Apply the thinnest layers possible to fill the surface. Let dry and repeat. Use a strong light at a low angle to evaluate the outcome. Then skim some more. There should be no sanding during this process, but you can gently scrape the surface to knock crumbs off.
4. Only once you're satisfied with the finish will you do a light sanding. This isn't about shaping the surface, but knocking of tiny crumbs and knife marks.
5. Retexture if desired.
6. Prime the surface and paint.