(I use a stencil designed for dolls houses to make bricks. They are actually 1/12 but look fine. I use Ronseal plastic wood in a tube for the bricks instead of the brick compound sold by the stencil manufacturers as this is not waterproof.
The advantage with this method is that once you have bought the stencil the ongoing costs are very low.
Bromley Craft products make the stencils and they do quite a range.)
You can also get these in 1/24 scale as well, brick,stone and slate. I use wickes waterproof filler then seal with a varnish. Colours are added or painted using cheap acrylic paints.