Can you paint over flat paint with glossy paint without priming first?

Answer 1

Yes. There are some factors that you have to answers yes to before proceeding. The flat paint that you are painting over needs to be clean and free of grease dirt and other markings (marker, crayon, ect.) All the holes or patches done on drywall mud or joint compound needs to be sanded and primed (not the whole wall but if there are many you might want do do so. Reason is that the gloss paint will show every imperfection on the wall like these. you might end up with a patchwork of smooth and semi smooth in one color. it is best to create a uniform texture to the wall before painting) Lastly, and this can be very important, the color of the paint will determine the need for primer. For example, a deep red like cranberry over a white wall needs a tinted primer or you will be putting 4-5 coats on to get the desired color look. You will learn the hard way when don't pay for the needed primer and the color will never come near the color you wanted. lighter colors are fine like taupe's. yellow's, gray's and some blue's. the best advice is to go to ANY paint store like Sherwin Williams (even the paint sections at Lowes and Home Depot will do great) and describe what you are doing and they will tell you what you need.

One last note, cheap paint will give you cheap results. I'm not saying that you need Ralph Lauren paints but no-name brands will result in a crappy finish!