What is a rafter

Rafters are nailed vertically in the trusses to bear the roof tiles of the wooden bars, it is in the paving lookout brick roof, the pitch can be slightly wider. Its cross-section of rectangular and round two kinds, round should be cut in the top 1/4, into a purse-shaped to lay nailed to look out for the board or look out for the brick, so there is a "purse rafters," the name. /zaojia/subsite/info/showinfo.aspx?infoid=56fe4b5f-ed7c-432a-9946-e8e303636ca0