How to Figure the Length of Steel Sheeting on a Hip Roof

Metal roofing can mimic the appearance of traditional roofing materials.

Although the initial cost of metal sheeting can be greater than other materials, its long life and resilience makes it an attractive alternative. Its physical properties help keep a building cool in summer and prevent ice and snow accumulation in winter. In some states there is a tax incentive for installing metal roofing. Calculating the length of steel sheeting for a roof is a straightforward task requiring no previous roofing experience.

Things You'll Need

• Tape measure
• Paper
• Pencil

Instructions

1. Measure the distance along the roof surface from the roof hip to the fascia board at the base of the roof span. Record the value. If the building is at the planning stage, ascertain the roof's height from the eaves to the hip, and its width from wall to wall. The length of the roof slope equals the square root of half the width squared plus the height squared.

2. Add the length of the overhang at the fascia board to the previous measured length. This is determined by the width of the guttering used, and its distance from the fascia board.

3. Consult the technical data for the metal ridge plate you intend to use. Ascertain the distance under the edges of the plate that the roof sheeting must extend. If the technical data calls for a ventilation gap to be left between the top of the sheeting and the ridge, deduct this distance from the sheet length. If there are no specific requirements, deduct 1 or 2 inches from the overall length. This creates a hidden space and allows adjustment of the sheet to achieve a straight edge along the roof's bottom.

Tips & Warnings

• Once you ascertain the correct length, get the supplier to cut the steel sheet for you. Suppliers can produce accurate and straight cuts that are difficult to do on site.

• Don't increase the roof overhang simply because your standard steel sheets are longer than you need. Excessive overhang may catch the wind and generate forces that can loosen the roof or lift it off the house.

• Do not go on a roof unless you take suitable safety precautions. Falling may result in serious injuries or death.

References

• New England Metal Roof: Residential Metal Roofing - The New King of Premium Roofs
• Florida Atlantic University: Pythagoras Theorem and Its Applications
• Builder Bill: Roof Sheeting Fixing

Resources

• Cleave Books: The Triangles Calculator