flaking and peeling garden wall paint

[busterfridge]

Every year i get this on my garden wall and i have to scrape it and repaint it, it bubbles when it rains in the winter then over a short time it brakes and flakes off, the wall was treated with PVA then painted with Santex outdoor wall paint. Would love to know what causes this to happen and what the solution is ?? cheers.

 

[KenGMac]

Moisture / dampness emanating from the ground behind the wall.

By now that wall is saturated, because of the above, so any paint will tend to be blown off by the moisture [in effect] pushing through the wall.

Suggest you consider, remove all the present paint [layers?]

let the wall surface dry out over this Summer, then apply a "Micro-porous" external paint which should assist in the paint adhering long term??

Ken