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


3 Responses to Ridge Board Length for a Hip Roof

  1. i am building a 12x20 hip roof pavilion shelter i am using douglas fir 6x6 post 3x8 for hip ridge beam and for the box or plate 3x6 for rafters and 2x6 tongue an grove pitch 4/12 i did not figure out exact sizes or over hang for eves birds mount would i be save on just 4/ 6x6 on the corners or i need another 6x6 for the 20ft in middle? is the 2x6 over kill i am using asphalt shingles on top worried about roofing nails going threw to ruin that wood affect i never did hip roof i am having a problem figuring out how much to order of rafters tongue an grove an cuts i have some idea but not exact on cuts heights thanx also the rafters no 16 on center or 24 splitting in even lengths an the over hang, box it into 3x8 so i can put high hats in with the tongue an grove and across the width two 3x6 for ceiling fans to hang on

  2. Hi
    I am building a 16 x 16 building and as you can see I can't deduct the longest from the smallest. I don't want a pointed roof peak. I would like some flat section on my hip roof. I also used 6 x 6 for corner and support posts. Any ideas?

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