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To calculate roof pitch and rafters using the Construction Master Pro, you only need to input any two known dimensions (such as Pitch, Run, or Rise) to automatically solve for common rafters, hips, valleys, cutting angles, and jack rafters. The calculator uses built-in right-triangle formulas, completely bypassing the need for manual geometry or trigonometry. 🟩 Step 1: Input Your Base Measurements

The calculator requires two variables to solve the entire roof. Most commonly, you will use the Pitch (the slope) and the Run (half of the total building span).

Enter the Pitch: Type the vertical rise inches, press the Inch key, and press Pitch. Example for a 7:12 pitch: Press 7 Inch Pitch.

Alternatively (for degrees): If your pitch is an angle, type the number and press Pitch directly (e.g., 30 Pitch).

Enter the Run: Type the distance, include the units, and press Run. Example: Press 11 Feet 5 Inch Run. 🟦 Step 2: Calculate Common Rafters & Cutting Angles

Once your two primary dimensions are locked in, you can pull all required common rafter details out of the Diag (Diagonal) button.

Find Theoretical Length: Press Diag. The screen displays the exact point-to-point length from the ridge centerline to the outer wall plate line.

Find the Plumb Cut Angle: Press Diag a second time. This gives you the angle needed for your vertical cut at the ridge board.

Find the Level Cut Angle: Press Diag a third time. This gives you the flat horizontal angle needed to sit perfectly on top of your wall plate (the “seat cut” of your bird’s mouth).

Find Total Rise: Press the Rise key at any point to see the absolute vertical height from the top wall plate to the top of the ridge. 🟪 Step 3: Calculate Hip and Valley Rafters

If you are framing a hip or valley roof instead of a simple gable, the calculator finds this length automatically relative to your existing common rafter inputs.

Find Hip/Valley Length: Press the Hip/V key. It instantly solves for the length of a standard 45-degree hip or valley rafter.

Find Cheeks/Plumb Cuts: Repeatedly pressing the Hip/V key cycles through the plumb cut angles, level cut angles, and cheek cut angles specific to that rafter. 🟨 Step 4: Calculate Jack Rafters

Jack rafters diminish in length incrementally as they move from the common rafter down toward the corner of a hip roof. The calculator defaults to a 16-inch on-center (O.C.) spacing, but you can store any custom spacing first (e.g., type 24 Inch Conv Jack to store 24-inch spacing).

Find Successive Jack Lengths: Press the Jack key repeatedly.

Each single press displays the exact length of the next individual jack rafter (e.g., “Jack 1”, “Jack 2”, “Jack 3”) starting from the longest common rafter down to the shortest corner piece. ⚠️ Crucial Field Adjustments

Keep in mind that all measurements provided by the calculator are theoretical geometric calculations. Before cutting your lumber, you must make two manual job site adjustments:

Deduct for the Ridge: Subtract half the thickness of your ridge board from the top peak of the rafter length.

Add Your Overhang: Add the length required for your tail overhang past the outer wall line to reach your fascia.

Watch these operational walk-throughs to see the keystrokes performed on the device in real-time: Pitch and Run Calculations | Construction Master Pro 16K views · 2 years ago YouTube · Calculated Industries Every Roof Framing Function on the Construction Master Pro 6.8K views · 2 years ago YouTube · Calculated Industries