Water based masonary paint over old gloss paint. Exterior

[Navy]

Hello everyone, I am just about to start painting the exterior of my house and would like to cover the old flaking gloss paint with a water based masonary paint.
I plan to sand the old gloss paint but was wondering what type of undercoat (if any) I should use. i.e water based or oil based before applying the masonary paint.
Many years ago I was told not to apply water based paints on top of oil based paints so how do I proceed?
Any suggestions would be really helpful. I am just a novice having a go so hope the above makes sense.

Kind regards
Navy

 

[Wayners]

Rub the gloss with meths. If any comes off it's waterbased paint. Just to confirm.

What is the gloss on? Wood or masonry?
Normally masonry would have paint which won't trap moisture which would cause problems.

Zinsser coverstain is a good option although allow 7 days before you paint over.

If you wanted to stick with waterbased primer then bullseye123 is good with correct preparation.

We really need more information. I want to understand why the gloss is flaking

 

[Navy]

Many thanks for replying Wayners.

The gloss is on masonry (sandstone decorative mouldings) I think. I am almost sure this was done many years ago with a stabilising solution then 2 coats oil based undercoat then gloss.

For many reasons, the paint has been left unattended for over 10 years and I want to get it sorted now.

I prefer to use masonry paint (if its suitable) as its much more simple for me to touch up in the future.

I am attaching a couple pics.
Kind regards
Navy

 

[Wayners]

Doubt you want to remove paint then alkali primer and paint.
I would sand then coverstain to prime. It's a good binder and will fill a bit, so two coats and a denib
Then 2 top coats of something like zinsser allcoat.

There are other ways to do it. Maybe someone else here can give an opinion

 

[Navy]

Many thanks again Wayners.

So I'll sand back to a smooth surface removing as much of the flaking paint as possible (not the sandstone) then two coats of zinsser cover stain.
I'm guessing I don't need a separate undercoat as the zinsser cover stain is an undercoat?
Then a denib.
Finally, Zinsser allcoat colour matched to my preference.

Many many thanks Wayners for your help which has given me the confidence to start this project. I really am very grateful your advice.

Kind regards
Navy

 

[Wayners]

Yeah.

Just give coverstain 4 good drying days before you top coat.
Spec is 7 days to cure but good drying outside 4 is fine.
No need for undercoat

 

[michealangelo]

Yeah.

Just give coverstain 4 good drying days before you top coat.
Spec is 7 days to cure but good drying outside 4 is fine.
No need for undercoat

How about pliolite on top of coverstain as a finish ?

 

[Wayners]

You dont need a primer with pliolite unless its powdery.
You will need to decide at the time how to prepare surface as the pliolite might go straight on.

I've never used pliolite over coverstain