How to build a gable porch

Updated July 20, 2017

A gable roof is triangular and typically appears above doorways and enclosures. It is the most common roof style for porches, as the sides are sloped to encourage snow and water to slide off the sides rather than accumulate. Adding a gable roof to an existing porch structure is a popular way that homeowners can add value to their residence and enhance its aesthetic appeal. A gable porch can also offer shelter from harsh weather like, excessive heat, snow and heavy rain.

Mark and cut the front porch overhang beans so they meet end to end, like a truss. Clamp an overhang rafter against a rafter of the other structure. Work backwards toward the home and to keep the fixture stable, brace the porch frame together.

Secure the truss and fasten it with nails on both sides. To keep the beams straight, extend a cord or string on the level from the peak to the highest peak of the roof. Nail the ridge board to the gable roof.

Set the valley rafter, beginning with the ridge board at the roof's bottom point up to the highest peak of the porch truss. Fasten the vertical rafters to the centre ridge board down the centre.

Identify the width of the shingles and sheathing used on the roof of your home and ensure that you are using the same materials on the porch.

Place the end of the sheath at the centre point of the centre roof truss. Roll the first piece from the bottom for about five inches. Be sure to add metal flashing on the valley of the roof, as well as along the low ends and edges. This method helps to prevent water damage.

Install the shingles to your roof, beginning at the bottom and working upwards. Paint the wood or siding of the porch to match or complement your home. Fasten all materials with a staple gun.


The size and spacing of your gable porch will be depend on the local building regulations and safety codes in your town or city. Be sure to check with your local building permitting department before you begin your project. Measure all of the sheathing before installing them onto the gable porch roof. An incorrect size can interrupt the full project.

Things You'll Need

  • Hammer
  • Staple Gun
  • Sawhorse
  • Skill saw
  • Framing square
  • Ladder
  • Tape Measure
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About the Author

Maris Callahan has been writing and editing since 2008. She is author of the food blog, In Good Taste, is a self-taught home cook and is knowledgeable about all things culinary. She contributes to several websites, including Shape, myGloss and Digging In, as well as to a "Chicago Sun-Times" food blog. She holds a Bachelor of Arts in writing and communications from Susquehanna University.