Best wall sealer for bare walls?

[jordcam1983]

So back in 2013 I had my new house painted. The guy who painted was a "professional" (hardly) and he said he had sealed the walls which he obviously didnt as you can see by the photos, 90% of my walls i can just peel huge chunks of paint off.

So ive been scrapping and peeling back to the bare walls (I live in Perth so the walls are brick with plaster set over top)and then applying a skim coat on the places my scrapper has taken bits of plaster away.

So once the bits of skim coat plaster has been sanded back smooth, whats a good sealer primer to use? 

I really wanted to use oil based but i have indoor animals that ive read it can be harmful for them to breath in, plus oil based takes longer to dry and dont want my animals hair getting stuck on the walls while it dries.  So i guess water based is what i need to use, but which one? Any info would be appreciated 

[Jewelleryrescue]

Hi

@jordcam1983 

This  solution may  raise  some  eye brows  but it is perfectly sound in application.

Wet  down  your  very porous plaster  with a  mixture 1 Part PVA Glue with 3  parts  water and let it dry  Use brush  and or roller.

Wont cost you the earth in expensive under coats.

[EricL]

Hello @jordcam1983 

I propose using Dulux 1Step Prep Primer, Sealer & Undercoat 4L. My best advice is to make sure that all the dust on the surface of your walls have been wiped away before you coat it with the primer.

If you need further assistance, please let us know.

Eric

[jordcam1983]

Thank you. Ill be wiping it down for sure. Ill use my vacuum with a brush attachment and wipe down the excess

[jordcam1983]

@Jewelleryrescue 

Have you used this mixture before?

[Jewelleryrescue]

Hi @jordcam1983 

I have used a very similar mixture before binding a dusty cement and brick wall ready for rendering.  My actual water mixture was bond crete which is very similar to PVA and it really works  well sealing  waterproofing and providing a good under base for  additional top coatings to stick too.

  Sounds  like  your plaster could use a little binding and the pvc coating allows paint to bind to it more easily but lets  prove it to our selfves  before you do  your whole  house you dont need another coating failure I have being there too.

I highly   suggest we do a test of the mixture I am sure you might have Aquadere in your shed or some can be bought in small bottle, mix some with water and try in on a test area inside a  cupboard  then paint it.

I was  just doing some economics and Shelleys Aquadhere PVA is  $21.95  for 500ml Mixing this into the water ratio will give us 2 litres only.   

So there is no gaining economically using this PVA  solution and @EricL    paint choice is the better paint choice with out the oil paint smell  or science project to test it 

I want you to  use a  sure thing you dont need this task again any time soon.

[jordcam1983]

The walls under the paint are quite dusty from removing the high quality paint🤣 

[Jewelleryrescue]

Hi @jordcam1983 

I am hearing you re dust. I also am thinking what you're not saying will the next paint layer come off too.

Ideally we need to bind that surface and dust.

This

Another Method for pure new real plaster walls not just powdery gyprock  is to mix up a paint emulsion a mist coat.  Simply put is your paint /under coat watered down 10 parts water one part paint 

Brushed or rolled on to a bone dry wall.  The  mixture should soak into the wall and help seal the wall let it dry to bone dry as well.

Last Resort

Maybe your pets   can go on a holiday for a couple of  days as the strongest commercial  sealer binders  seam to be oil based. 

Dulux PRECISION® Sealer Binder is an oil-based prepcoat that seals porous surfaces and binds unpainted powdery surfaces such as bare plaster, cement sheet and brick to provide a sound foundation to apply subsequent paint coats.

• Suitable for use under Dulux topcoats
• Oil-based
• Interior and exterior use

• Available in 1L, 4L, 10L
• Available in White base
• Seals porous surfaces and binds unpainted powdery surfaces such as bare plaster

It  says  chalky paints it bonds too further down on the can

Dulux 4L PRECISION White Maximum Strength Adhesion Primer I/N: 1400849    $111^.50

[jordcam1983]

So i have a 10L tin on dulux 1 step primer sealer water based in my garage, so u say mix 10 parts water to 1 part of this and roll/ brush it on first? Then a coat of undiluted  dulux 1 step, then paint colour on top? 

[Jewelleryrescue]

Hi @jordcam1983 

Yes exactly that but make sure the plaster is bone dry before all coats.

By  plaster I am talking about a real  plaster wall as chalky as they come.

After the 10 parts coating  feel it with your hand see if the process helped.

This  tip comes for my Croatian painter neighbour and he is a  good  painter.

Never need to  exactly do this to  a wall yet so haven't tried first hand just so you can weight up the quality of the information.