After removing wallpaper should one sand the area where wallpaper was to prepare it for painting? What are the steps involved before painting?
The amount of preparation before painting depends on how the wallpaper came off the wall and if any damage occurred during its removal. Typically the main aspects of preparing a wall after stripping wallpaper is priming and patching.
Sanding usually isn't necessary, but if the walls are excessively rough or have small amounts of paper remaining then sanding is a good idea.
Try to make sure all remaining wallpaper backing is removed before priming. The backing paper should come off while washing to remove the glue.
Check the walls for remaining wallpaper glue. If it seems excessive, wash the walls with warm water, a mild soap can be used but isn't necessary with most wallpaper glues. Small amounts of wallpaper glue is O.K., it will be sealed by the primer.
Priming will seal any remaining wallpaper glue. Any good paint primer can be used, a fast drying universal acrylic primer is the easiest to use and readily available through your local paint store. After the primer is applied any defects in the wall will be more apparent.
All defects will need to be fixed before painting. This includes any gouged areas that might have happened while stripping the wallpaper. Large repairs will need priming before painting, but if applying two coats of paint most small repairs will be sealed with the first coat of paint. (Check out <a href="https://www.house-painting-info.com/drywall-repair.html">Repairing Drywall</a> for more information.)
Glue Residue
My concern is using a latex primer when there may be some glue residue remaining. I usually use an oil-based/alkyd primer after wallpaper removal just to be safe. There are a few odorless and low VOC options.
I am currently removing wallpaper on a home where there are 3 kids under the age of 5 and cannot use anything oil-based. Not even odorless or low VOC alkyds are kid-safe as far as I know. I was going to wash the walls extensively and use Benjamin Moore's Fresh Start Acrylic primer and hope the glue doesn't come through. Does anyone know of a better latex primer for this?
Good acrylic primer.
Zinnser 123 is really good and another is Gripper. You are right that an oil based primer is best, Kilz works really good. The biggest problem with oil based primers is the smell.
Any acrylic primer could dissolve the glue. In this case let the primer dry (a couple of hours) and apply a second coat.