Q:

Can I paint over wallpaper glue?

I have a room where I removed the wallpaper in preparation for painting. Surprisingly, the very old wallpaper just peeled right off, leaving behind most of it's glue. I used some wallpaper remover spray to quickly clean up the few spots where some of the backing paper stayed behind, so now the wall is just drywall covered almost entirely with a thin layer wall paper glue.
I tried using the wall paper remover to take off the glue, and it works well, but is tedious and time consuming (compared to how easily the wallpaper itself came off).
Is it really necessary to take off this glue? Will new primer and paint adhere to it as well as it would to the drywall or am I asking for trouble with premature peeling paint or other problems down the road?

A:

You will need to take off all the glue if you want a good finish.
The paint will lift the glue, but unevenly, and mix with the paint. This will cause the paint to clump and not cover properly and all in all it will look terrible.
I know because I did this in the first house I owned and had to wash the walls of the one room where I tried this several times to get as much glue off as possible. I don't think I got it completely off and you could still tell.
If you just want to paint the room, you would be better off hanging lining paper and then painting that. This has the added advantage (especially if you use 1000gsm paper) of covering any imperfections in the wall.

