To paint over semi-gloss paint, do I really need to sand before the primer?

I'm going to re-paint a couple of bathrooms that are currently painted with semi-gloss paint. Can I just put primer over the semi-gloss or do I really need to sand?To paint over semi-gloss paint, do I really need to sand before the primer?
I don't sand it in a major way, I just go over it quickly with one of those sponge/sandpaper things


The main thing is make sure there's no oil or soap on the surface.


That 1.2.3. stain block is the best primer I've ever used. I've even painted over glossy surfaces and ceramic tiles.To paint over semi-gloss paint, do I really need to sand before the primer?
You can just put on the primer let it dry and they paint on your base coat. I usually repaint the interior of my house at least once every 18 months -- get bored of the current color. I just apply a primer and then the next day apply the base coat. I like Behr sold in Home Depot it really does a great job covering. I used to use Glidden (it was cheaper) but then I had to apply several coats to cover the walls. With the Behr its just one coat of primer and one coat of base coat.
there are some primers that are heavy duty enough for it but it would be better to give the wall a quick sand with a fine grain sandpaper. It will give you a cleaner end coat
All you need to do is wipe the wall down with TSP solution, available in the paint department of home improvement stores. Wear rubber gloves too!
Don't need to prime or sand, just wipe on some gloss cutter sold at home centers. Just sanding with 150 grit sandpaper will get you there too.
If you purchase a good quality primer you can get away with priming without sanding. As far as sanding, it's not like what is necessary when hanging drywall, you just need to lightly rub sandpaper over the surface of the wall - not too much effort exerted, really.





But, at least do primer, I know people who've put on paint over semi-gloss and had the new paint virtually slide down the wall. The previous owners of my home did this in the bathroom - what a mess!





I've had several people recommend 1-2-3 by Zinsser as a primer and it worked well for me. Covered dark blue walls without a second thought and then I covered it with a light color.
Rather than buy a product like gloss cutter, use a kitchen pan cleaner, the scouring type. That's enough to get a key into paint. I prefer to sand (Or rather to aluminium oxide on a roll paper) to ensure I get a mirror finish.
Yes, put a primer on the wall if you do not want the shine to come through. Primer, also make it so you do not have to put two coats of paint on the wall.


I personal use all kelly moore paints.