How to Box in Roof Overhangs

Boxing a roof overhang protects the structure against outside elements.

Roof overhangs, or eaves, may be boxed in for aesthetic reasons, to better seal the home from weather or animals coming in, to better insulate a structure or as protection against fire. Roof overhangs can be boxed using a variety of materials, ranging from aluminum or wood to vinyl, and painted to your liking. Boxing requires covering the front, or the fascia, and the bottom, or the soffit, of the overhang.

Things You'll Need

• Soffit material
• Fascia material
• J channels
• F channels
• ¾-inch wood screws
• Screw driver
• Nail gun (using 10d nails)
• Hand-held circular saw
• Measuring tape
• Pencil
• Protective gear

Instructions

1. Calculate the amount of material required for the soffit. Measure the underside of the overhang area and multiply the length by the width for each stretch of overhang. Measure the length of the front of the overhang to calculate the linear feet needed for the fascia as well as the F and J channels.

2. Cut the tail ends off the rafters at an angle perpendicular to the ground. Finish by squaring the bottom edge of the rafter.

3. Cap the end of the overhang with a 2-by-4 cut to the length of the linear feet needed for the fascia board.

4. Screw in the F channel, using a screwdriver, directly below where the roof meets the wall. Insert screws every 6 to 12 inches. Check the channel's level against the bottom of the 2-by-4 rafter cap.

5. Screw in the J channel to the end of the soffit directly across from and level with the F channel. This creates a track to slide the soffit panels into and also provides support for the vertical fascia board.

6. Slide the soffit panels into the F and J channels. If the soffit material is wood, secure the panels to the rafters with nails.

7. Nail the fascia board to the cornice of the rafters to cap the roof overhang, utilizing the J channel as support.

8. Insert the appropriate number of vents in the soffit panels in accordance with your local building code.

9. Paint the new boxed overhang to your liking.

Tips & Warnings

• Wear eye protection when cutting the rafter tails.

• Observe safety precautions if working on a ladder.

References

• Clemson Extension; Controlling Moisture with Overhangs and Flashing; 1997
• The Free Education Network; Building Construction and Finishing: Roof Sheathing; 2007
• Mitten, Inc.; How to Install Guide