Setter Spacing for Flat Roof Tiles: The Support Interval That Keeps Firing Warpage Within a Stated Tolerance

This paper addresses flat clay roof tiles that warp during firing because they are supported too far apart while soft at peak temperature. It presents a maximum setter-spacing rule from beam sag of a tile at firing temperature, derived entirely from stated assumptions and a computation whose code and full output accompany the paper. The sweep covers setter support spacing from 100 to 400 mm. The headline outcome is: largest spacing within tolerance mm 300; bow at 400mm 5.45; bow at 200mm 0.34. These figures identify a specific operating point or bound that a workshop can apply directly, and they also show how quickly performance deteriorates away from it. No kiln was built, no ware was fired, and nothing was measured for this study. SIMULATED, NOT MEASURED.