Stones on drive/impact on house

[Anotherpointofview1]

We recently laid stones on our drive and up to our house. Since we laid them, the bottom of the house wall seems to be growing a thin layer of green stuff (I guess because it's watery on the bricks or something). Its definitely something to do with stones as it wasn't like that before. We are moving them at the weekend so that there's a gap between them and the wall but does anyone know why/what is happening? @pigletjohn or anyone else any ideas? Is it to do with wet stones being against the wall? Have attached photos.

Are the stones covering the damp course?

Possibly covered the DPC? Have you got a good drainage membrane down?

scrape away the stones and let's see what's beneath. This may also show the DPC, if it is beneath the stones

also stand back and show a wider pic

the damp seems to be leaving an efflorescence. Are you on chalky or limy soil? Or in a hard-water area?

Do any drains or downpipes discharge into that channel?

The wet is worst at or about the level of the stones, so is probably evaporating where exposed. The damp seems to stop two bricks above, which might be where the DPC is, or it might be where evaporation balances absorbtion. Damp cannot easily travel into clean bare bricks through a mortar bed.