Damp render on newly rendered Shed

[GG1977]

Recently had a shed built with 2 breeze block skins, with a damp proof course bit the northside of the building, which literally gets no sun has damp and green algae forming. Wondering why this is like this and is this a concern? Need to finish painting and add a stabiliser on top too. Picture attached.
In summer if it rained it would get wet then dry up.

 

[jj4091]

The render should not have gone to the floor. There should have been a Belcast beading then a gap but it also depends where the DPC is. It looks like it is either the render soaking water up from the base or water splashing up onto the render. Use one of these products https://www.google.com/search?q=spr...RioAxiLA5gDAJIHBDE1LjGgB6-GAQ&sclient=gws-wiz to get rid of the green algae but I'm not sure what can be done about the damp before you decorate. I'm sure someone else will be better able to advise on that.