Installing Roof Sheathing: 5 Tips

Roof sheathing is an integral component of the framing. It is also referred to as roof decking. It acts as a base for the roof covering. You drive nails into the sheathing as you attach the underlayment and the shingles. The sheathing is nailed onto the trusses and rafters and may be solid or open. Sheathing contributes towards the resilience and rigidity of the roof. Commonly used materials for sheathing are plank lumber and plywood. Well installed roof decking helps to create a smart roof. Below are 5 tips.

1.   Fastener Selection

The right size of fasteners is vital to proper sheathing. Use the recommended type for your particular roof design. It is best to use nails with full round heads to fasten the sheathing panels. This prevents head pull-through which helps to maintain your sheathing in good shape. Use deformed shank nails in areas along the eaves, ridges and gables, to give the roof higher resistance against gusty winds. Staples should be avoided, especially if you live in a high wind area, as they do not give adequate support to sheathing.

2.   Installation and Spacing of Fasteners

Be sure to drive in the nails firmly and securely. Nails that aren’t connected securely to the roof structure contribute to a weak roof. It is vital that you space the fasteners as stipulated. Do not cut down on the fasteners to be installed, as it compromises the integrity of your roof. Certain areas are bound to require closer spacing such as corners, ridges and edges.

3.   Sheathing Placement

It is vital that the sheathing panels meet at the centers of the rafters. This contributes to a symmetrical appearance when roof installation is finally completed. To achieve this, you need to install the panels along the eaves so that they’re perpendicular to the rafters. You can then progressively move upwards towards the ridge as you install additional sheathing. Be sure to maintain a uniformly straight, perpendicular center line as you progress. It may be necessary to trim the final panel at the top if it exceeds the available space.

4.   Space Allowance for Solid Panel Sheathing

Select a lower roof corner to begin installation. Place one panel horizontally across the rafters. If you live in a high humidity area, leave a gap of 1/8 of an inch between the connecting widths and ¼ of an inch between connecting lengths. Use half of these measurements if you live in an area with normal humidity. Should the boards swell due to humidity, the gaps will give them adequate room to expand so that no damage is caused to adjacent boards.

5.   Protect the Sheathing

It is best to cover the sheathing with roofing felt once installation is completed. This helps to prevent damage by excessive moisture and other weather elements before the final roof covering is put in place. Be sure to clean the surface thoroughly before you place the felt. Smooth and flatten the felt as much as possible. A uniformly even surface makes it easier to install the roof covering.