No Gap Between Roof Sheathing Panels

Not always required but a good idea.

No gap between roof sheathing panels.

Connections between the roof sheathing and the gable truss. 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. The critical fasteners occur at the ga ble framing member not necessarily at. Use a 10d box nail to gauge 1 8 inch spacing between panels.

Leave a 3 mm 1 8 inch gap between the osb panels to allow for expansion. However it is not a requirement. Spacer type panel edge clips may also be used for roof sheathing applications. Provide a 1 8 inch gap between the panels in each row.

Use a 10d box 0 128 inch by 3 inch nail as a spacer to gauge 1 8 inch edge and end spacing between panels. This gap prevents buckling of panels due to moisture and thermal effects a common problem. Panel spacing is an apa recommendation to provide installers with a means of minimizing the potential for panel buckling. Some manufacturers may.

Panel edge clips or some other type of edge suppoprt like blocking are only required for structural ratings with thinner panels and larger support spacing like 3 8 sheathing on roof trusses 24 o c. Keep nails 3 8. Stagger the panels over the roof with 2 supports between panel ends. 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.

Edge clip requirements depend on the relationship of the panel span rating to the actual distance between roof framing. When you sandwich the layers so there is no air gap you only get the insulation value of the closed foam in the prodex material. Fastener selection an 8d nail 2 5 inches long is the minimum size nail to use for fastening sheathing panels. Nail the panels to the rafters with 8d common nails spaced 6 inches apart on the ends and 12 inches apart in the middle.

Roof trusses must be dry when sheathing a roof with osb to prevent mold growth in the roof and coverage gaps as the trusses dry and shrink. Some older h clips do not provide a built in gap. By no means am i an expert on insulation but from what i ve read you need to have an air gap between the foil facing and the exterior material like the shingles or sheathing under it.