I think the point Mick was trying to make is that the model railway fraternity make a lot of buildings, I know I used to be a railway modeller, and therefore have a whole range of techniques for creating and painting brick and masonry.
Therefore it worth doing a trawl of these sites to identify which paints might be suitable for your needs.
Also worth looking through any model railway mags in your local news sellers as they are forever runing how to's on buildings.
Karl