“塞缝”用英语怎么说？

[建筑学]拱顶石:位于拱顶的塞缝石.Architecture The keystone in the crown of an arch.用防水原料填塞缝隙或塞缝片一年也能节省一千七百磅.Caulking and weather - stripping can save another 1,700 pounds per year....

“塞缝”的拼音为：sāi fèng...