30 percent roof rule 4

https://city-wiki.win/index.php/5_Signs_You_Need_a_New_Roof:_A_Homeowner%E2%80%99s_Guide_to_Repair_vs._Replacement

The 30 percent roof rule suggests that the roof area should cover no more than 30 percent of the total building footprint to maintain visual balance and prevent a top-heavy appearance. Architects often use it as a guideline for residential designs, ensuring the roof doesn't overwhelm the structure's proportions. It's not a strict code, but a practical tip for achieving a harmonious look, especially in neighborhoods where uniform aesthetics matter.