water proof on pebbledash gable end

House is 1908, Sheffield, Hillsborough, red brick typical terraced house, end terraced, gable end is cold and damp, cellar is wet, roof and gutters are good condition. Ventilation is an issue but gable end wall is wet to touch is some small areas and the whole end is damp and has black mould in the edges and corner, particularly in a small walking wardrobe that is effectively in the cold most exposed end of the house.
I am going to look at installing a PIV (positive input ventilation) device but also want to make the gable end waterproof. It's going to be a big job as access is rubbish, sloping bank etc, pictures allowed on this site?
Would like to use a coat of paint or spray on method, what do you guys recomend? I would be really interested in hearing if it ok to go for no breathable, this house has barely any cavity and it will be benefiting from better ventilation with PIV and therefore should dry from the inside.
Have read some interesting debates on here and consequently decide to give as much detail as poss on this house so we can get specific on it rather than talk about topic over a range of different housing. If any more detail is required please let me know.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.