Roof Valley framing, a crucial skill for any builder, takes on new levels of complexity when dealing with roofs of unequal pitch. The goal is to achieve a seamless transition where two distinct roof angles intersect, making it a challenge even for the seasoned builder. However, with a method that is swift, precise, and intuitive, you can overcome these complications.

Demystifying the Roof Valley Framing of Unequal Pitch Roofs

Often, the construction of roofs with differing pitches can involve intricate geometric relations that may seem insurmountable at first glance. Fears of intricate calculations and graphic projections are common, especially among builders with less extensive framing experience.

However, our approach to this predicament focuses on simplicity. We have devised a strategy that replaces complex calculations and models with practical, straightforward techniques, allowing builders to execute their work without the burden of math-induced apprehension.

Implementing a Non-Mathematical Approach

Understanding that not every builder retains a passion for trigonometry, our method turns away from complex mathematical modeling towards a hands-on, field-oriented approach. We emphasize the use of practical tools like strings and levels to design and lay out complicated roof structures.

This technique has been proven to offer fast, accurate, and easy-to-understand results. Moreover, it reduces the need for constant revisions and fixes. It is a streamlined, efficient way to conquer the intricacies of unequal pitch roof framing.

Application on a Typical Unequal Pitched Roof Framing

To provide a clearer understanding, we apply our method to a typical project involving unequal roof pitches. The process begins with the ridgeboard – the primary structure that holds the rafters in place.

The length of the ridgeboard is determined by adding the ell (shorter side) and half the main roof length, subtracting half the ridge width. Once this length is obtained, the ell ridge is cut accordingly and the rafter spacing marked out.

The ridgeboard is then positioned accurately at the main ridge, secured with nails, and double-checked for plumb alignment over the gable wall. Stability is maintained using a temporary diagonal brace.

Simplified Approach to Ell Common Rafters

Following the ridgeboard’s placement, the ell common rafters’ layout is fairly simple. A rafter stock is pinned against the ridgeboard’s end and the wall plate’s corner, scribing for the bird’s mouth and the plumb cut.

Adhering to the rule where the seat cut begins at the top plate’s inside edge, the position and depth of the bird’s mouth are established. As the rafter tail length decides the distance between the fascia and the wall, the rafter tails on the ell must allow for a continuous flow from the ell fascia into the main fascia.

After cutting two rafters, they are tacked to the ridge to test the fit. If the fit is accurate, proceed to the next step.

Valley Framing for Unequally Pitched Roofs

The diagram above represents the relationship and sequence of the construction process. From positioning the ridgeboard, laying out the ell common rafters, to finalising the fascia, each step follows a logical and straightforward progression.

The Connection Between Roof Framing and Roof Valley Replacements

Roof framing lays the foundational structure for the entire roofing system, including roof valleys. It is crucial for managing the water flow off the roof, directing it into gutters and downspouts. When a roof valley fails due to wear and tear, damage, or faulty installation, professional roof valley replacement becomes necessary. During the replacement process, understanding the original roof framing is essential. It informs the builder about the roof’s geometric layout and helps accurately position the new valley. Furthermore, any adjustments or enhancements needed to the roof framing can be addressed during a valley replacement, strengthening the overall structure and ensuring a more durable and efficient roof system.


Emphasising simplicity and practicality, our method provides a reliable and non-mathematical approach to valley framing for unequally pitched roofs. By using these techniques, builders can confidently undertake complex roofing projects, resulting in a seamless and structurally sound construction. Remember, the key is in mastering the use of simple tools like strings and levels, coupled with a thorough understanding of the roof’s physical aspects. Be prepared to undertake any challenge that unequally pitched roofs may present and turn them into opportunities for creative and resilient building solutions.