The bit with all the blue paint doesn't seem that great. To be frank, it looks like you took MSPaint and just waved the mouse around. I actually thought it was a paintover on top of the screenshot, but perspective shows that it's on top of the wood.
If you want to have a "blue takes over red" building, it would probably look better to scrap the paint and instead add a BLU sign in the process being nailed over the RED one. Then you could detail the area with a couple extra BLU signs leaning against the wall, a ladder, a box of nails, etc. There also is a decent-looking set of stuff for paint in the SDK, like a paint roller and paintbrush+bucket prop, and I think an overlay for a partially painted wall.
I also don't really like the wall-o-cart in your other pictures but I don't have a great idea for how to change that beyond swapping it for chemical tanks or something. Overall your buildings' structure looks good so with more work on details you'll have a great entry.