Functional Mason Bee Hotel — Research-Based Design

A mason bee hotel designed around actual research recommendations from the Xerces Society and university extension programs — not just for looks. Most cheap commercial bee hotels fail because the holes are too shallow, too wide, or too rough. This one gets it right. Specs (based on Osmia lignaria / blue orchard mason bee research): 81 tubes in a 9×9 grid — 8mm diameter (5/16"), 152mm deep (6") Smooth tube walls — rough interiors deter occupancy Solid back wall — closed end is required for egg-laying 13mm back wall behind tube ends for structural integrity 32mm front roof overhang + 10mm side overhangs for rain protection Landing perch along the bottom front edge 8mm mounting hole on the back (fits M8 bolt or standard screw hook) Overall footprint: ~170mm W × 180mm D × 165mm H Print settings: Material: PETG or ASA recommended for outdoor durability (avoid PLA) Supports: Minimal — only the front roof overhang may need bridging support (~30mm span) No infill tricks needed — the tube walls