Need Painting Help?

Question

I painted a room with a light blue in satin. I was unhappy with the look. I was thinking of re-doing it in either flat or eggshell. Do I need to sand it down or prime it first. Or can I just paint over it. I was really thinking of using the flat.

Thankyou for your time.

Mark

Answer 1

I just repainted over (without sanding) but with the matt finish (flat) I needed more than one coat.

Answer 2

If same brand, no priming. If different brand, I would prime.  Stay with same brand and bring in a fan to keep air moving.

Answer 3

If you are converting from a satin to flat you may need to prime to prevent "mud cracking"  which is hair line cracking all over the whole surface. This happens when you paint a less flexible paint (flat) over a more flexible paint (satin).  This is similar to the cracking you see if you paint a flat paint over caulk.  

Will you get mud cracking for sure - I don't know - but it is a big enough problem to fix so I wouldn't take the chance. Always use a oil (such as Zinsser's Coverstain) or shellac ( such as Zinsser's BIN) primer to convert a semi gloss or satin latex down to a flat latex (don't use a latex primer).  Provide good ventilation when painting with the solvent based primers.