Should Roof Sheathing Have Gaps

The left hand number is maximum spacing for when used for roof sheathing with long dimensions across supports while the right is for flooring.

Should roof sheathing have gaps.

Never attach roof sheathing with staples. If asphalt shingles are installed over sheathing with gaps exceeding 1 4 inch over time these gaps may telegraph through and become visible. If the flatness of sheathing or flooring panels is acceptable apa would generally recommend that any finish flooring siding or roofing be installed as planned regardless of whether gaps are present. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame.

Not always required but a good idea. The correction recommended by manufacturers is installation of an additional layer of 3 8 inch minimum exterior grade plywood or osb roof sheathing on top of the original wood board roof sheathing. Occasionally you may see one of two terms here. Everywhere you can see snow on the roof roof is insulated good if you have some areas where snow has malt this is the heat from home going out 2 absolutely truth but 50 years ago.

The roof s sheathing helps to keep the roof trusses or rafters properly spaced and is the strength that holds. Sized for spacing refers to a panel that is trimmed a fraction shorter so that when installed with the proper expansion gap it will equal its nominal size. Some older h clips do not provide a built in gap. H clips provide additional stiffness between bearing points for the unsupported edges of wood panel plywood or osb roof sheathing along with the necessary 1 8 gap for expansion as shown below illustrated on a bag of simpson h clips.

Roof sheathing is a lot more than just flat panels onto which shingles are attached. The current vendor of the house claims that the reason for the gaps in the roofing visible from inside the atic is that it is a breathing roof. 8d ring shank nails should be used instead. The typical thickness range for sheathing is 3 8 to 3 4 inch.

Would require panel edge clips for support see item 7 under fastening hints on pg 2 of the attached apa guide n335 and footnote d.