Why are ancient roofs made of tiles, and there are gaps between tiles, so there is no water leakage?

It won't leak, because the function of ceramic tile is waterproof. The key to not leaking rain is to lay tiles. There are more than one layer of tiles, which overlap and pile together. The last one is connected to the next one at 7/ 10, and then the tiles are connected to each other. Finally, tile mud is covered on the tiles, and each layer can play the role of waterproof and thermal insulation.

Extended data:

Waterproof and moisture-proof of ancient dwellings;

1. External wall: adopt permanent brick wall building that is not afraid of flooding, and paint the bricks anew. This can not only prevent moisture and insects, but also set off the green environment in the water system area, forming an elegant beauty, that is, white walls and black tiles, small bridges and flowing water.

2. Architectural structure: the "four waters belong to the hall" style is mostly adopted. Taking the traditional "room" as the basic unit, the rooms in the house are mostly odd, usually three or five. Each room is 3 ~ 4 meters wide, with high walls and large width, and the front and rear doors are connected to facilitate ventilation. Rubble is often laid at the bottom of the wall, and slate is also laid on the indoor floor. The single buildings are connected by corridors and form a closed courtyard with the courtyard wall to facilitate ventilation.

3. Drainage channel: make full use of the characteristics of dense river network, build houses along the river, take the river as the street, and connect the streets and bridges. For example, Tongli ancient town is surrounded by water. The town is divided into 7 small islands by 15 river and connected by 49 bridges. Every family in the town is near the water and has a boat. Ming and Qing dynasties houses, row upon row. Zhouzhuang Waterway in the ancient town can go straight to the house, and the owner can get on the boat without leaving home.

Baidu Encyclopedia-Tile (Building Materials)