How to convert from the run of your regular roof to the run of the irregular roof

You can always convert your known run to the unknown run by using the ratio of the 2 pitches. So here, if we know the run of the 8 in. pitch is 10 feet, we can divide by 12 and multiply by 8 to find that the run of the 12 in. pitch is 6 ft 8 in.
But remember, the Construction Master Pro and Construction Master 5 can handle all of the math for you on irregular hips and valleys. Here’s how you could also find the 12/12 run using the HIP/V function:
1️⃣ Push 8 INCH PITCH
2️⃣ Push 10 FEET RUN
3️⃣ Push 12 INCH HIP/V
4️⃣ Add the common difference (INCR) between your irregular 12/12 jacks to your longest jack
5️⃣ Enter that value (your irregular common rafter length) as your new DIAG
6️⃣ Push 12 INCH PITCH and then RUN
Both methods give you the same value of 6 ft 8 in. and are a great way to make sure you’ve got your head on straight 🙃. Which we could all use more of these days...