How to Box Frame Roof Eaves

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  • 4-7 hours
  • Advanced
  • 1,500
What You'll Need
F channels
J channels
Nailing strips
Undersill trim
Soffit board
Inside and outside corner posts
8 penny nails
Fascia cap
3/4 inch wood screws

The appearance of your home can be greatly improved if you box frame your eaves. Open eaves are a fire hazard since they can let in sparks which can quickly set the roof on fire. If you reside in an area where wildfires occur, you should box your eaves to prevent the danger of fire.

Another advantage boxed-in-eaves have over open rafters is that they make painting the exterior of your house easier, as you only have one long flat surface to paint instead of having to paint the individual ends of exposed rafters. Eaves are boxed in with fascia boards and soffit panels; these can be made of a variety of materials such as asbestos concrete board, different types of wood and vinyl.

Step 1 - Prepare the Eaves for Soffit Installation

Using the ¾ inch screws secure the F channel or J channel to the sides of the eaves for the soffit panel to slide into. Do this beneath the eaves, all round the house. F channels are fasteners shaped like an “F” through which the soffit board will slide in. Nail your undersill trim into place.

Step 2 - Inspect Your Fascias

Check that the interior of the fascias connected to the rafter trails have grooves to provide a space for the soffit boards to rest upon. You can also install J channels with the wood screws to provide that slot. Also make sure that the fascia board is projecting below the rafters so that when its boxed in the lower edge of the fascia board is lower than your boxing otherwise moisture will enter into the boxing.

Step 3 - Attach the Soffit Boards

Soffit panels are available in many different materials and also come in unvented and vented styles, so make sure you know which type is suitable for your needs before purchasing. Cut the soffit panel to size and using the 8 penny nails, secure the soffit board to your F channel. Remember to allow ¼ of an inch at each end of the adjoining walls for expansion. Ease the soffit boards into the fascia slots or alternatively, into the J channel.

Step 4 - Apply a Fascia Cap

Install a fascia cap to your fascia board to support the soffit and stiffen the supporting J channel and to enclose the front of your eaves.

That’s it, now you can enjoy the fruits of your labor. Box framing your eaves greatly enhances the appearance of your home making your eaves look infinitely tidier. There are many different materials you can choose from when boxing your eaves such as vinyl, which is very easy to install and maintain but not as effective as metal for fireproofing. Wood is also used and provides great insulation. Aluminum is a good material for boxing and has good fire resistant properties. Boxing your eaves increases the value of your property and dramatically minimizes the danger of fire.