Question on Roofing shingles & shakes

I have a question about wood shingles & shakes should have “solid or spaced plank sheathing” my question is what do they mean by “solid” because I was thinking plywood being solid sheet but that’s not recommended.

They want to have 1X material under the shakes for stability and to properly anchor the shakes with nails. Sheathing is not recommended but used all the time here.

http://inspectapedia.com/BestPractices/Wood_Roof_Sheathing.htm

http://forums.jlconline.com/forums/archive/index.php/t-37793.html

http://www.inspectorsjournal.com/forum/topic.asp?TOPIC_ID=14350

I would say that solid sheathing refers to standard structural panels or T&G. Skip sheathing “battens” is always dimensional planking that is spaced for air circulation. Cedar shingles needs to breath a bit underneath to control cupping, which is the reason for skip sheathing. In FL, it is banned to use skip sheathing due to wind loads on the structure, but I would think that 5/8" plywood would be fine for cedar roofs with a secondary step moisture barrier laid over each course.

There are very specific standards for cedar shakes and shingles. I remember that there were different requirements for the northern climates vs the southern.

Cedar shakes that have the certain chemical treatment (I forgot the name) will overcome the problem and can be safely installed over plywood or other solid sheathing.

ACQ Marvin.

Gary,
Take a few minutes and find your questions answered by what InterNACHI provides about wood shingles and shakes in their Mastering Roof Inspection series.

  1. Mastering Roof Inspections: Wood Shakes and Shingles, Part 1
  2. Mastering Roof Inspections: Wood Shakes and Shingles, Part 2
  3. Mastering Roof Inspections: Wood Shakes and Shingles, Part 3
  4. Mastering Roof Inspections: Wood Shakes and Shingles, Part 4
  5. Mastering Roof Inspections: Wood Shakes and Shingles, Part 5
  6. Mastering Roof Inspections: Wood Shakes and Shingles, Part 6
  7. Mastering Roof Inspections: Wood Shakes and Shingles, Part 7