Gap Between Roof Sheathing And Insulation

Use baffles between each rafter space to prevent it from being blocked see figure 5 11.

Gap between roof sheathing and insulation.

Roof sheathing panel spacing hints. The moisture is held in place by the insulation which allows for damage to the framing and other building components. 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. Apply adhesive along the connection between the roof sheathing and rafters in a continuous bead much like caulk around a bathtub or apply adhesive to two adjacent sides of 1 by 2 blocks 6 inches.

The problem arises with moisture. Spacer type panel edge clips are available from some manufacturers. The gap between the roof sheathing and the insulation over a ceiling is varied between 1 and 3 inches. To maintain airflow leave a space of 38 to 50 mm 1 1 2 to 2 in between the top of the insulation and the underside of the roof sheathing.

Or if you are perfect with your rainwater control such as when you use a fully adhered membrane think roof membrane standing up applied to a wall. There are no irc requirements for spacing wood sheathing that i am aware of. Batts should cover the top plate of the exterior wall but not block the venting. T he problem with the insulation against the sheathing expands.

An air space between the insulation and the bottom of the roof sheathing is desirable. The code calls for a minimum of 1 in. For best performance the airspace in the vent chute should be a minimum of 2 in. Unless you provide a small gap between the exterior face of the osb and the back surface of the foam sheathing to provide for some hygric redistribution.

Of airspace between the top of the insulation and the back of the roof sheathing. If there is a roof leak the insulation will be damaged by the water leaving you with less insulating value. Unless you re bulk filling rafter bays between 2 10 or 2 8 rafters with closed cell spray foam this approach.