Can you make a roof pitch steeper or change it?
Short answer. Yes, a roof's pitch can be changed, but it means removing the roof covering and reframing with new rafters or trusses, which requires a permit and usually an engineer or architect. Because that is a structural project, many homeowners with a low slope problem solve it instead with a roofing material rated for low slopes.
Why people change pitch
- A porch or addition built too flat for shingles, leaking at every hard rain.
- Gaining attic or living space under a steeper roof.
- Matching an addition to the main house for curb appeal.
- Converting a flat roof that keeps failing to a pitched one.
What the work involves
- Design by an architect or engineer for rafter or truss sizes, loads and connections.
- Building permit and HOA approval where applicable. See roofing permits in Georgia.
- Removing the old covering, and often the old framing.
- New framing, sometimes built on top of the existing low roof, called overframing.
- New decking, underlayment, flashing and roofing.
- Inspection, then siding, gutters and trim tied back in.
This is a framing and carpentry project first and a roofing project second.
Cheaper fixes for a low slope
- Know the limits. Asphalt shingles need at least 2/12 slope, and between 2/12 and 4/12 the code requires double underlayment.
- Below 2/12, switch to a membrane system or a standing seam metal panel rated for low slopes.
- Flash the transition carefully where the low roof meets the main roof or wall; that joint is where most low slope leaks start.
To see how pitch is measured and what it means for materials, read roof anatomy explained.