What is a 5/12 pitch in roofing?

A 5/12 pitch means that for every 12 horizontal units, the roof rises 5 vertical units. This creates a slope that is often used for gable roofs.

How do I calculate the rise of a gable roof with a 5/12 pitch?

To calculate the rise, you can use the formula: Rise = (Span / 2) * (Pitch / 12). For a 16 ft span, the rise would be (16 ft / 2) * (5/12) = 5 ft.

What is a plumb cut in roofing?

A plumb cut is the angled cut made at the top of the rafter to fit against the ridge board. It must match the roof pitch to ensure a proper fit.

Why is snow load important in roof design?

Snow load is crucial because it affects the structural integrity of the roof. It is important to size the roof to handle potential snow accumulation based on local climate conditions.

5/12 gable rafter on a 16 ft span

Explore the essentials of gable roof design with a 5/12 pitch on a 16 ft span. Learn about multipliers, plumb cuts, and the importance of snow load considerations.

Formula SSC-2026.1

5.00 / 12 · 22.62°

Pitch angle

22.62°

Multiplier 1.0833

Common rafter

9 ft 8 3/16 in

Tail 1 ft 1 in

Cuts

22.62° plumb

67.38° seat

Roof area

503 ft²

5.03 squares

Shingle bundles

3 bundles per square + 10% waste

Sheathing / felt

18 sheets

2 underlayment rolls

Delivery weight

2,074 lb

941 kg · 70 lb bundles, 46 lb sheets, 28 lb rolls

Gable truss triangleLive scaled blueprint

Rise and run are scaled from the span, overhang, and pitch. The small triangle is the pitch ratio.

Bill of materials and shopping list
Item	Net	Waste	Order	Unit price	Line total	Source Spec Material / Tool
Architectural shingle bundles	5.03 squares	10%	17 bundles	USD	$714.00	Source Spec Material / Tool
4x8 CDX sheathing	15.7 sheets	10%	18 sheets	USD	$504.00	Source Spec Material / Tool
Underlayment rolls	503 ft²	overlap allowance	2 rolls	USD	$110.00	Source Spec Material / Tool
Ridge cap bundles	26.0 ft ridge	—	2 bundles	25 ft per bundle	—	Source Spec Material / Tool

Source links open a product search on the Amazon storefront for the selected currency. SiteSpecCalc may earn a commission. The link does not change the quantities above.

Side-by-side pitch comparison
Pitch	Degrees	Multiplier	Rafter	Squares	Bundles	Sheets
5.0/12	22.62°	1.083	9 ft 8 3/16 in	5.03	17	18
7.0/12	30.26°	1.158	10 ft 4 3/16 in	5.38	18	19

Show the deterministic formula

Angle = arctan(rise ÷ 12). Multiplier = √(1 + (rise ÷ 12)²). Gable run = span ÷ 2 − ridge thickness ÷ 2. Rafter length = (run + horizontal overhang) × multiplier.

Plumb cut = pitch angle. Seat cut = 90° − pitch angle. Area uses both slopes on a gable and one slope on a shed, and it includes a rake overhang equal to the eave overhang.

Bundles = ceiling of squares × 3 × 1.10. Sheets = ceiling of area × 1.10 ÷ 32. Rolls use 360 ft² effective coverage. Delivery weight plans 70 lb per bundle, 46 lb per sheet, and 28 lb per roll, then the header converts that pound total at 1 lb = 0.45359237 kg.

Contractor sign-off

Project: 5/12 gable rafter on a 16 ft span

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This sheet is an estimate for ordering and layout discussion. It is not a sealed design. Confirm the quantities with a licensed local professional and the authority having jurisdiction before you buy or build.

Engineering notes

A gable roof with a 5/12 pitch indicates that for every 12 horizontal units, the roof rises 5 vertical units. This ratio is crucial for determining the roof's slope and overall structural integrity.

The multiplier is used to calculate the total rise of the roof based on the span and pitch. For a 16 ft span, the rise can be calculated using the pitch ratio. Additionally, the plumb cut refers to the angle cut at the top of the rafters, which must match the roof pitch to ensure proper fit and structural support.

Code reference

Consult local building codes for specific requirements regarding roof design, including snow load considerations, which should be assessed based on regional climate conditions.

Field questions

What is a 5/12 pitch in roofing?: A 5/12 pitch means that for every 12 horizontal units, the roof rises 5 vertical units. This creates a slope that is often used for gable roofs.
How do I calculate the rise of a gable roof with a 5/12 pitch?: To calculate the rise, you can use the formula: Rise = (Span / 2) * (Pitch / 12). For a 16 ft span, the rise would be (16 ft / 2) * (5/12) = 5 ft.
What is a plumb cut in roofing?: A plumb cut is the angled cut made at the top of the rafter to fit against the ridge board. It must match the roof pitch to ensure a proper fit.
Why is snow load important in roof design?: Snow load is crucial because it affects the structural integrity of the roof. It is important to size the roof to handle potential snow accumulation based on local climate conditions.