H-Clip
An H-clip is a small metal bracket shaped like the letter "H" that fits between the unsupported edges of adjacent roof sheathing panels, providing edge support and maintaining the required 1/8" expansion gap between panels.
In Detail
H-Clips for Roof Sheathing
H-clips (also called panel edge clips or plywood clips) are stamped metal devices installed at the unsupported long edges of roof sheathing panels — the edges that fall between rafters or trusses, where there is no framing member to support the panel edge.
Purpose
- Support unsupported panel edges to prevent differential deflection between adjacent panels (one panel sagging lower than its neighbor under foot traffic or snow load).
- Maintain the required 1/8" expansion gap between panels without relying on the installer to measure.
- Transfer load between adjacent panels at the unsupported edge.
When Required
Per IRC R803.2.1.1, edge support is required for roof sheathing panels when the rafter/truss spacing equals the first number in the span rating. For example, a 24/16-rated panel installed over 24" o.c. rafters needs H-clips or T&G edges. If the rafter spacing is less than the span rating (e.g., 16" spacing with a 24/16 panel), edge support is not required.
One H-clip is required between each pair of rafters along the unsupported panel edge — typically 2–3 clips per 8-foot panel edge.
Related Terms
Span Rating
A span rating is the pair of numbers stamped on structural panels (like 32/16) indicating the maximum recommended center-to-center spacing of supports — the first number for roof rafters and the second for floor joists, both in inches.
Tongue and Groove
Tongue and groove (T&G) is a joint profile where one board edge has a protruding ridge (tongue) and the mating edge has a matching channel (groove), allowing panels to interlock for a tight, self-aligning connection without unsupported edges.
Related Materials
CDX Plywood
This is a test description for CDX plywood as we work on the technical backend of the website.
OSB (Oriented Strand Board)
Oriented strand board (OSB) is an engineered wood panel made from compressed wood strands bonded with waterproof resin. It is the most widely used structural sheathing panel in North American residential construction, offering uniform strength properties and lower cost than plywood.