Kitchen Wallpaper If A Kitchen Wallpaper I Painted Little More Than A Year Ago Is Brittle And Cracking, What Might I Have...?

If a kitchen wallpaper i painted little more than a year ago is brittle and cracking, what might i have...? - kitchen wallpaper

... wrong?

could be a case of using the wrong kind of paint for the kitchen [the right way is ]....
Or is it that the paint on, I somehow reacted with the screen and caused the explosion heard?

The same happens with Artex near a window, I drew on ... ARTEX, begins to crack and crumble in some places.