Why not try HIPS Plastic, held together with Pipe Weld and Pins can survive outside very well. But have to say best in the shade.silo and Factory on the left are made from this. Building to front right is from Wood covered in Silo Sand and Painted external Paint Grey.
View attachment 211075
Cheep Playmobil or other Kids buildings sourced cheeply from Boots Sales or Garage Sales can be converted to all sorts of things. This I think Regency House has made two Station Buildings and a Hotel.
View attachment 211074
This Wooden Box coated with Corrugations from Baked Bean Tins has been outside for over 6 Years now and is surviving very well. The Tinplate is going a bit Rusty, but that is what I wanted.
View attachment 211072
This buiding made from Decking, Lolly Sticks and HIPS has been outside over 10 Years now and was built for my friends line and came back to me when he died 3 Years ago.
View attachment 211076
Another cheep Toy, would benefit from a Repaint but I like something bright to interest the kids.
View attachment 211077
On the left a £1 Bird House, had suffered the ravages of Time probably 12 or more Years now. But the Lead Flashhing Roof scribed for Slates has saved its bacon. To the right a very crude shelter made from 1 x 1.5 inch timber and at least 20 Years old. From a friends line when he got out of Garden Railways for a while.
View attachment 211078
The Water Tower made from Cement Bits off cleaned up Bricks, glued with a cheep external glue and filled with Concrete when dry. Middle an upturned Flower Pot and on top a cheep Garden Ornament Roof. Door Plasticard and Frame Rocket Sticks. Over 10 Years old now. Misc Pottery Buildings, Grey one an old Tom Cooper one not available any more getting on for 20 Years old.
Lead flashing covered with Gafa Tape makes great roofs and is used on a few of my Outside Buildings.
There are many cheep options out there, just a bit of imagination is all you need.
JonD