Upgrade path

Plain Wood Barricade02 Center Plate→ 4× Wood →Window Plug 03→ 10× Cobblestone Rocks →Cobblestone Block→ 10× Concrete Mix →Concrete Block→ 10× Forged Steel →Steel Block

Hit a placed block with a stone axe, claw hammer or nail gun while carrying the material of the next step: 4 hits per upgrade.

Where to find (14 POIs)

Flushing Rule Palace (tier 4), Mason Farms (tier 3), Pop's Pawn & Bel's Bakery (tier 3), Boar Barn Fields (tier 2), Mason's Barn (tier 2), Mo Power Electronics (tier 2), Bath Haus (tier 1), Bert's Brewery (tier 1), Cole's Books (tier 1), Pass-N-Gas Store #03 (tier 1), Rifle Martyrs (tier 1), The Malone Residence (tier 1), The Clutter Chest, The Joelton Hotel.

Points of interest built with this block (any of its variants), the highest tiers first, from the game's prefab files.