This is actually depends on the formulation of the paint, nowadays a lot of paints have gone for the development of Low VOC and elastomeric route, which the formulation actually results in lower dirt pick-up resistance. But on the other hand, it solves other common problems in our humid weather such as efflorescence. There really isn't any perfect formulation yet in the market, it really depends on how the paint manufacturer take the balance between these properties. There is not much we can do with the choices in the market except to look for hydrophobic coating to protect the paint films. In my opinion I would rather use the most common exterior product (Jotashield in your case) and do regular maintenance for decorative purpose.

Actually both also almost the same. For exterior paint certain colour I would recommend Jotun, for interior I would say Nippon is great. This is based on my own experience only.

Cheers

The molds are still there, your paint won't last that long until it turns back to the previous look. The proper way is to do high pressure water jet first, then apply Fungicide and leave overnight to kill fungus spores. Then proceed with normal painting system with 1 coat sealer and 2 coats finishing.

Btw it looks like you were using overly-thinned sealer or base paint with water/ inferior grade paint. The hiding is pretty poor.

Water jet to wash off the old loosen paint films and fungus, then apply fungicide and leave it for 1 day. Wash it off the next day and allow it to dry first before subsequent painting. Use proper exterior grade wall sealer and finishing.

1 coat wall sealer
2 coats finishing

If you don't overly thin your paint, normally the above system should be enough.

Colour really does not matter much, although yellowish off-white and darker colours look less dirty as stains are not that visible on these colours.

It is not true that coloured paints are better than white colour, pastel based colour including white normally contains more Titanium dioxide (what we call white powder) thus provide better hiding.

Ya Matex is economy grade interior paint and is not suitable for exterior application. Weathershield/weatherbond is the go for exterior grade paint.

Those are ok, no problem with the paint. Just prep the wall nicely before painting.

Cheers

It really depends on the environment. But it's normal to paint after a month. If your contractor has protimeter, request to test the moisture level to be below 16 to start painting.

If the paint is already been there for some time and no defects (Water mark, powdery, bubbles etc), just go ahead with your finishing coat to overcoat on top of the existing finishing.

Sealer is not needed if you wall paint is still at good condition (No water mark, no bubbles, not chalky, etc...). If there are holes you would have to patch up with skim coat, then apply sealer before painting.
Otherwise, just repaint it directly, I would suggest to wipe and let it dry before painting finishing coat.

Roller wise just go to hardware store and get those branded rollers. I normally use Anza and Nippon's paint rollers, consider paying a little premium to avoid other hassle.

Just saw your post and would like to share some information on this problem. This is efflorescent and is a very common problem in Malaysia, the root cause of this problem is actually moisture transferring the soluble salts from walls/plaster, seep out to the surface and crystalized to become the white solid. If there is no cracks on the wall surface for water to penetrate in, there are a few possible causes that may lead to this problem:

1. Improper painting system
2. Inferior sealer quality
3. High moisture level in the wall while painting
4. Direct contact to ground causing ground water to transfer to the wall

Now we know the root cause of the problem is the moisture inside the wall, assuming that the wall condition is still good, the best way to prevent it from happening is making sure the wall moisture content is always below 16% before painting. If the requirement in some circumstances are not able to achieve, base on my experience the solution would be by using strong alkaline resistance paint like this one, or any acrylic solvent-based wall sealer to replace the conventional water-based sealer. Alternatively you can also opt to apply a thick layer of acrylic based water proofing coating as sealer before subsequent painting if the wall moisture is constantly remain at the higher side.

Your solution should always be making sure the wall moisture level is low, and/or preventing the moisture from transferring the soluble salts out to the paint surface.

This post has been edited by PaintPals: Dec 27 2020, 06:22 PM

It is called protimeter and ranging from basic to professional. You can invest in a basic one to check if there is suspect water leakage or any types of wall damage due to moisture. In normal condition that you washed the wall/reskim, just leave it for one day to paint it on the next day.

Glad to hear that you solved your wall problem, that is how a professional painting work is done.

Go for Satin finish Paint like Jotun Majestic Beauty Sheen or Nippon Satin Glo, that will give your shop a bright and fresh look, but on if your walls are skimmed to smooth finish. Otherwise just go with the conventional maxilite/matex range will do if budget is a concern to you.

Go for low-sheen/satin finish that provides good washability and premium finish (again provided that your wall surface is smooth). No worries on fading on interior paints, fading normally occurs due to organic pigments being degraded from UV. Normally in normal interior condition no issue for internal paint ya. Just go for reliable brands, some brands' economic range are powdery.

Have been using matex/maxilite for my project works so far no problem. I am not sure about your cold room metal material, but matex/maxilite these types of copolymer/modified acrylic paints are only suitable for wall surfaces (masonry, brick and plaster etc.)

For Nippon Paint products, if it is not very chalky then use

1 coat of 5200 Wall Sealer
2 coats of Easywash or other finishing as per your preference

If it is very chalky/powdery, I would advise using solvent base sealer such as Hi-bond wall sealer or 5170 acrylic wall sealer to replace 5200 wall sealer. However you have to ensure good air flow for your house and nobody staying in it for some times as solvent based paint can be really smelly.

The difference between 5200 and 5400 is mainly the formulation and (probably) the latex used. I myself used both and found that 5200 has smoother finishing, if you are going after a good interior finish for your own house I would personally choose 5200 over 5400.

To add on ceo684 reply above, if the chalk is on top of the old paint surface and the old paint film still binds well to your wall, then can just wipe off the powder on surface, let it dry and apply solvent based styrene-acrylic wall sealer before your next coat of finishing.

Do take note if your existing paint is solvent base then have to check on the type of the paint used to avoid solvent attack, if existing paint is water based then no problem. The only downside from this is the pungent smell produced from the solvent.

Can have a lot of different possibilities of causing the problem depending on many factors i.e. Exposed or non-exposed, type of skim/plaster, type of paint material used. You can share more photos of the problematic walls or engage a certified painter from the manufacturer to check on the problem directly.

Not much difference in term of sheen and colour between True Beauty Sheen vs Perfect beauty & Care, both are low sheen and looks great on perfectly smooth skim coated walls. Go for Majestic Truee Beauty Matt is you prefer matt finish.