For items falling through floors check your bbpsettings.json.

I forget which setting specifically fixes it but it should work with the following settings:

"BBP_FloatingPlacement": 1,
"BBP_CanRaiseAndLowerHologram": 1,
"BBP_HologramHasCollision": 0,
"BBP_InventoryToggle": 1,
"BBP_BarbedWireRemoveOutside": 0,
"BBP_CanAttachFlashlights": 0,

Please fix your cement mixers too! Default mixer positions and spawning are broken.

- Add this line to your cfgignorelist.xml to prevent multi-spawning lag-making mixers:
<type name="BBP_Cement_Mixer_Static"></type>

- There's also a cement mixer position typo in bbpsettings.json. One of the positions has an exponent e-06. Should be numbers only so remove the exponent part.

Lastly, but not least, please add a fancy wallpaper mod like BBPBeergardenWallpaper to your servers, or make your own custom ones, so players can decorate the inside surfaces. Sell them at a trader or, if you don't want traders, do what I did and create loot points around plank piles for them to spawn at.

<3