Q&A / 

Ridge Board Length for a Hip Roof


David Ellis of Illinois asked "how do you figure the length of the ridge board in a hip roof garage?"

David, the ridge board for a common hip roof is easy to calculate. You measure the length and width of the structure to and from the actual building line.

The building line is the point from which you start to calculate the run of your common rafters to the centerline of the roof.

I also assume you'll be using a 2x material for the ridge board.

Subtract the shorter wall length from the longer wall length< and add 1.5 inches for the length of the ridge beam or board.

Example: Let's say I'm building a shed that measures 10 feet by 16 feet. These are the measurements of the walls once covered with my sheathing and create the actual rectangle of the roof line.

16' - 10' = 6 feet

6 feet plus 1.5 inches = 73.5 inches for the ridge board

You have to add the 1.5 inches because that accounts for the king rafters that connect to each end of the ridge board just like the common rafters that touch the sides of the ridge board.

Tim Carter


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