Things You'll Need
"F" and "J" channels of equal lengths
"H" bars, 1 for each corner
If you can see the roof rafters underneath the eaves, you may want to fit cladding to cover them up. Cladding -- known as soffits -- makes the underside of your eaves look neat and tidy. They can also help protect your roof from pests and are easy to clean. Fitting soffit cladding is a straightforward job as long as you take a step-by-step approach and are comfortable with heights.
Measure the depth of the eave from the edge of the roof to the wall using the tape measure. Making your way around each side of the house, measure to ensure the depth is even from various points. Measure the length of each side of the roof at its leading edge and add the measurements together. Multiply the total length by the depth of the overhang to determine the size of the area to be covered. Divide the total area by 100 to determine how many lengths of cladding you'll need.
Calculate the needed number of fixing channels by multiplying the total length of the roof -- at its leading edge -- by 2. These channels are sold in strips and are called "F" channels, which are fitted parallel to each other. Depending on the structure of the roof, you may need to use an equal mix of "F" channels and "J" channels. "J" channels are suspended from the underside of the roof along its outer edge.
Measure the distance from the corner point of the wall beneath the overhang to the corner tip of the roof. Multiply this by the number of corners in the roof to determine the length of any required "H" channels. "H" channels are needed to fix corner pieces together.
Mark a line just beneath the rafters using a spirit level to keep the line horizontal. Secure a length of "F" channel along the line using nails hammered through the channel's mounting slots. Leave the nail heads poking out by 1/32 inch each to allow the channel to expand during hot weather. Continue attaching the "F" channels around the whole house. Fix the "F" or "J" channels opposite the "F" channels you just fitted, keeping them parallel all the way around the roof.
Cut the "H" channels to size for each corner so that they reach from the corner point of the wall to the tip of the roof. The "H" channels are fitted when your cladding reaches to the corner; the "H" channels are supported by the cladding panels.
Deduct 1/4 inch from the depth of the roof overhang and mark this length on the cladding. Soffit cladding is sold in lengths that are fitted width-ways under the eaves, so the cladding need to be cut to length. Cut the cladding using tin snips and check to ensure it properly fits into the "F" and "J" channels with 1/4-inch wiggle room alloted for heat expansion.
Measure and mark the cladding at the same lengths and cut both using the tin snips. Corner pieces need to be mitered using a protractor. Place the protractor on the outside corner and mark a line toward you at a 45-degree angle.
Insert the cladding panels into the "F" channel and fix using nails hammered into the nail plate. Slip the other end into the "J" channel. Fit the next piece of cladding so that it locks with the first panel and nail into the "F" channel nail plate and slip the other end into the "J" channel. Fit the remaining cladding until you arrive at a corner.
Slide a cut corner piece of cladding into the "F" and "J" channels and nail in place. Slip the "H" channel over the cut corner. Fit the adjacent corner piece into the "F" and "J" channels and push the cut corner edge into the "H" channel. Fix in place with nails hammered into the "F" channel nail plate. Continue fitting the remaining cladding.