For our Peninsular War skirmish project, I bought a set of MDF buildings from Empires at War.
These are excellent kits. I bought the "prepainted" version, which meant that the external faces of the walls were coated with a textured sandstone coloured paint. This served as both a primer and basecoat for the walls. Once assembled, I used a large make-up sponge to dab white paint over the surfaces, avoiding the bases of the walls and around doors and windows, which gave a weathered look to the buildings.
The pantile roofs were styrene sheets, while the spines of the roofs were provided in the form of a coloured, scored dowels; a coat of watered-down red-brown craft paint tied the two together, and provided the weathering effect.
One of the packs came with a frame missing, and so I couldn't build a storage bin on the side of the building, and had to make my own doors out of balsa - but it was an easy fix.
I will certainly buy from the range if I want to expand my collection of pantile roof buildings.