Another carpentry problem encountered while building a California style roof. A California style roof involves building one roof over another existing roof. In such a scenario, a section of the new roof, called the fill, needs to be built on top of the existing roof.
The video highlights a potential issue that can arise when connecting the new roof section (fill) to the existing roof. The carpenter encountered a bowing issue in the roof sheathing (plywood sheets that form the base of the roof) when attempting to create a straight line between the two roofs. This bowing would have resulted in an uneven surface if left unaddressed.
Then the importance of checking the roof sheathing for straightness before installing the final roof covering.
Here are the key points covered in the video:
Identifying the Problem: We demonstrate how to use a straight edge, such as a six-foot level, to identify any gaps between the existing roof and the new sheathing. The carpenter points out a large gap on one side and a smaller gap on the other side, indicating that the sheathing was bowed.
Potential Consequences: Then warns that if the bowed sheathing is left unaddressed, it can lead to an uneven roof surface after the final roofing materials are installed. This unevenness might be visually displeasing and could potentially affect the roof's functionality.
Grinding the Sheathing: It suggests grinding down the high spots of the bowed sheathing to achieve a level surface. However, the carpenter cautions against over-grinding as it can reduce the thickness of the sheathing to a point where it becomes difficult to nail the roof covering securely.
Acceptable Variations: Greg discusses the acceptable variations in the straightness of the roof sheathing. The carpenter suggests that a deviation of less than half an inch from a straight line is likely invisible under most roofing materials like composition shingles. Even a one-inch deviation might not be noticeable on roofs with thicker shingles or wood shakes.
California Roof Specific Challenges: Greg concludes by mentioning that the problems encountered in this video are more likely to occur when building a California style roof. This is because California roofs involve an additional layer of sheathing on top of an existing roof, which increases the chances of encountering unevenness.
Overall, the video provides valuable insights for carpenters who are planning to build a California style roof or any roof that involves adding a new section over an existing one. It highlights the importance of checking the roof sheathing for straightness and taking corrective measures, such as grinding, to ensure a smooth and even roof surface.
