Frae Wikipedia, the free beuk o knawledge
A ruif in Poland. It haes widden tiles.

A ruif is the top pairt o the biggin. It keeps oot the rain an the snaw an pertects fowk frae the sun. Some ruifs are sclent sae the rain an snaw faw aff eithly. Some ruifs are flet, but even flet ruifs hae a wee bit o a sclent sae the watter can flowe awa towards a cundie.

Flet ruifs are for ordinar kivered in cahootchie or kynds o plastic. You can walk on a flet ruif. At the laggin o a flet ruif thare is whiles a ravel, that hinders fowk frae fawin aff the ruif.