Catbarf and MacPhail - lovely weathering!
Here's some of mine:
Painted with Army Painter Army Green and Vallejo Basalt Grey (Or maybe Neutral Grey) drybrushed with Light Grey. The graffiti was made up on the
PC, printed and glued onto the wall panels.
Army Painter Necrotic Flesh spray for most of this. Handpainted graffiti, this time.
Based with AK Interactive Rust Basecoat, and some red patches brushed on, drybrushed with orange and then given a liberal and rough coat of Army Painter Dry Rust.
Based with Rust Basecoat, then a coat of Army Painter Plate Metal, and then Dry Rust and a Vallejo Beasty Brown drybrush here and there.
This uses a dark brown spray basecoat and then a coat of a 'chalky finish' beige, bought from the local hardware store. Weathered with Beasty Brown.
Army Painter Wolf Grey spray, weathered with a sponge of Vallejo Heavy Charcoal.
Army Painter Ulramarine spray, weathered with Heavy Charcoal and Beasty Brown.
Black with a light drybrush of Boltgun Metal. The walls are mirrored cardboard.
More brown and chalky spray. This was built from a yoghurt tub and half of a Christmas bauble.
Laser cut card kit, with some modifications. Sprayed with Army Painter Army Green, highlight with Coat D'Arms Putrid Green and weathered with Heavy Charcoal and Beasty Brown.
Various hardware store grey and white sprays.
For the curious, there are plenty more buildings, along with walkthroughs of their construction,
here!