Is it worth using breathable primer and paint over mdf wainscotting?

[Pari]

To tackle the damp issue in some of the ealls of my lower ground floor (condensation mostly, and 10 cm. of 2 walls earth retaining), I have taken the advise from this lovely forum and stripped 1m of the walls back to bricks, and will do wainscotting with vents to be able to live while monitoring the brick condition before plastering in the future. Using mdf wainscotting panels.
My question is: Is it worth spending more on breathable primer and paint (Claypaint) on mdf...when mdf inherently is not breathable? If it doesn't make any diff. for condensation, will just use normal paint and do replastering with lime and Claypaint in future after bricks dry.

 

[noj]

Most MDF turns horrible with moisture. I'd be inclined to paint the back of it with something waterproof before installing!

 

[Cubist]

MDF is little more than highly compressed shredded paper and is nearly as absorbent as kitchen towel. If you must use the stuff then do as @noj suggests and paint all the faces and and edges before using it.

 

[Pari]

What material should I use then for wainscoting? Thought wood will warp...and moisture-resistant mdf is more suitable?

 

[Cubist]

As I understand it the room you are dealing with includes two external walls that are fully exposed to atmosphere outdoors whist the two remaining walls are at least partially buried below ground.

On which of these walls do you want to install the wainscotting?

 

[Pari]

The wainscotting is all internal in the lower ground floor bedrooms. This basement extension believe was done about 25 years back. Wainscotting will be on 4 walls. Bottom 10-15cm of these have damp.
1 Wall faces external (rendered outside, render in good condition), and 3 internal. Of the external wall, the bottom 10cm is below ground. The other 3 are internal partition walls, but the bottom of these walls is damp due to condensation and for one of them think the DPC is compromised, so moisture from soil. I'm putting LVT on floors and they will put DPM on floor. That means moisture may continue going to these adjoining walls.

I'm thinking of putting Moisture resistant MDF, as PVC will look tacky and wood may warp? What's a suitable material?

 

[Cubist]

Condensation always appears high on walls and almost never upon low sections of any room. Any damp you are seeing in/on walls below head height will be due either to rising damp through the foundation/floors or penetrating damp from wet earth lying against the exterior of the wall or perhaps washing down the exterior face of the wall.

 

[Pari]

Ok. So, it's likely penetrating and rising damp from wet earth. This can't be changed. So, what wainscoting material to cover - that'll sit about 3.5cm from the wall? And is it worth spending more to put breathable primer and paint at all on wainscoting and skirting boards?

 

[a twig]

As we discussed in a response to one of your previous threads:

I’ve used wainscoting in the past - hacked the plaster off, attached 50mm battens to the wall with DPC to isolate them from the wall, then attached marine ply to form the wainscoting vented top and bottom with nice brass vents

 

[a twig]

You don’t need breathable paints on the marine ply, the air will be circulating behind it via the vents