四分比丘戒本疏 2.52

2.52

Twentieth, the precept against supervising the roofing of a house exceeding three tiers. Examining the meaning of the vinaya, 'three tiers' means three layers of roofing. This is because excessive layers cause the building to collapse and invite criticism, hence it was regulated. One may supervise the roofing of two layers; if the third is not yet finished, the monk must stay far away from where it can be seen or heard; otherwise, he commits an offence. 'Doors, leaves, windows, and casements' and so forth describe the features of the house, not the delineation of the offence.