You can make some pretty neat stuff using cereal boxes. That is what I used in creating this engine house, also several other buldings over the years:
View attachment 167378
Over time I purchased roofing material also some fake stone for the walls, plastic windows, etc; however in the meantime my wife the engine house as shown in the picture.
This was painted with a coat of automotive primer.
The process for making this is on my "Daves Layout V. 4.0 " thread under " layout design and construction"
Dave LASM