Jan 14 , 2019
How to Install Soffits Project: overview and materials
Aluminum is a good solution for wood soffits and fascias in awful shape. It’ll take less time to bury them behind aluminum trim than to repair, scrape and repaint the old wood. This article will tell you everything you need to know to do it yourself, including how to make an inexpensive soffit-cutting table that works every bit as well as the pricey units the pros use.
Do it yourself and save big bucks. If you’re not afraid of heights and you have basic hand tool know-how, you’re perfectly capable of cladding the fascias and soffits on your home. As you’ll see, the thin, light aluminum trim is easy to bend and cut with inexpensive tools. Other special pre-bent parts make installation a snap. Working alone, you can clad the soffits and fascias on a 1,200-sq.-ft. house in about five days. Get a volunteer to cut and hand you up materials and you’ll really move along. The materials are expensive, but you’ll save a lot more than that by doing it yourself rather than hiring a pro.
Fix the roof first. If you hide problems, they’ll only get worse! Chances are, if your soffits or roof framing is water damaged, you have serious roof problems that you must solve before starting this project. Even though water won’t damage the new aluminum, you may actually accelerate underlying wood decay by burying evidence of leaks. Common problems are ice dams, shingle edges that are broken off or that don’t project far enough, and even sagging shingles that form a trough just behind the fascia. You may even need a new roof. If you’re not sure, have a pro make the call before you start.
Just figuring out what everything is called is half the battle! Soffit panels are available in 12-ft. lengths, 12- or 16-in. widths and vented or unvented. Vented soffit has thousands of perforations that allow air to flow through but keep insects out. Solid (unvented) soffit has no perforations. Most installers use only vented material, even in areas that don’t need venting, such as gable ends (the peaks at the ends of roofs). Make your life easy—stick with 16-in. wide ventilated panels to simplify ordering and to cover large areas faster.
To calculate quantity, multiply width by length (in feet) of each soffit surface, add them all up to get total square footage and divide by 16 (the square footage of one 16-in. panel). Add 5 percent extra for waste and overlaps.
Aluminum fascia goes directly over the wood fascia and has a lip at the bottom that laps over the outer edge of the installed aluminum soffit. It comes in two standard widths: 6 and 8 in. Measure the width of your wood fascia to determine which width to buy. Measure the entire length of the existing fascia in linear feet, and divide by 12 to establish the quantity of 12-ft. fascia and J-channel sections needed. Then add 5 percent.
J-channel is a (surprise!) J-shaped length of aluminum that the soffit fits into against the house. Use it to anchor any edges of soffit not covered by aluminum fascia.
Metal drip edge may already be on your home. It projects from under the shingles and directs water away from the surface of the fascia. You can reuse existing drip edge if it’s in good shape and you’re happy with the color.
To calculate the number of pieces of drip edge, divide the total linear footage of the outer perimeter of the roof edge by 10. Then add 5 percent.
Easy does it. Don’t bother climbing around on ladders to measure your soffits and fascia (you’ll get enough of that later). Measure the walls and “guesstimate” overhang lengths to get an approximate total. On gable ends, hold a tape measure at the approximate roof angle, at the halfway point of the wall (directly under the peak), to get lengths for gable trim.
Figure A: Aluminum Soffit and Fascia Parts
Shop for these standard parts. Other special parts are also available.
Note: You can download and print Figure A from the Additional Information section below.
Prep the old roof edges
Prep the soffit
Remove existing shingle molding and frieze boards and replace any rotten fascia. Cut in additional soffit venting where necessary and remove existing soffit grilles to improve airflow.
Begin the job by pulling off the gutters. Removing gutters can be a real drag, but they may be reusable—if they survive the removal intact and if the color matches the new trim. Some aluminum styles are easily kinked, so have someone help you take them down. If you’re planning to reuse them, leave the drainpipes in place and simply disconnect them at the elbows. Steel yourself; you may end up having to replace the gutters along with the new trim if things don’t go well.
Most homes already have soffit vents. They conduct outside air into the attic to help prevent ice dams in the winter and keep attics cool in the summer. It’s best to remove existing vent covers for freer airflow before installing ventilated soffit panels. You should have about 1 sq. ft. of vents for every 300 sq. ft. of ceiling area, so add more holes if you’re lacking ventilation. The holes don’t need to be pretty; they’ll be covered with new material. For ease of cutting, position new holes in the spaces between the soffit framing (look for soffit nails to locate). For even ventilation, space holes fairly evenly across each soffit section.
Fascia board repair
The old wood fascia boards must be sound enough to hold the new fascia nails. Check the wood quality by jamming a screwdriver tip into the wood. Replace punky or rotten wood with straight pine boards the same width and thickness as the old.
Shingle moldings are narrow trim boards nailed to the top of the fascia if gutters aren’t used. They, like drip edge, direct water runoff away from the face to forestall weather damage. Pry them off with a flat bar and pull any leftover nails to prepare for the aluminum.
If the house has frieze boards (trim boards directly below the soffits), pull them off unless their removal leaves an unfinished gap between the siding and the new soffit. If that’s the case, leave it and butt the J-channel against it. Removing the frieze board is optional. Do it if you ever expect to replace your siding. That way, you’ll be able to strip off the old siding without wrecking the new soffits.
Aside from the jigsaw, none of these tools costs much, so it’s usually cheaper to buy rather than rent them. Home centers carry the same quality tools the pros use.
- Pair of tin snips for cutting straight lines.
- Pair of right or left cut snips for cutting curves, if you have circles to cut (for example, round lights and electrical boxes).
- Trim nail punch for holding and setting nails into soffit grooves and tight places. Combination square for making clean fascia bends to go around corners.
- 12-in. folding tool for making small bends in fascia. Jigsaw for cutting vents and removing projecting corners.
- Carpenter’s square for squaring up the first soffit panel to the house.
- Hammer, utility knife, tape measure, chalk line.
You Gotta Build this Quick, Cheap and Easy Cutting Table!
Cutting dozens of soffit panels with a pair of snips is tiring and crushes the grooves together. A circular saw makes clean, precise cuts easy—when it’s coupled with a cutting table. You can make a plywood-cutting table (Fig. B) in about an hour. The 45-degree side of the table is for cutting miters on hip roof soffits (see “How to Handle Soffit Corners on Hip Roofs.”).
Use a plywood crosscutting blade mounted backward—the saw teeth point down in a clockwise direction. Before reversing the blade, make a pass halfway through the top of the plywood saw table to create a saw blade groove. This allows the blade to cut completely and cleanly through the aluminum. For multiple cuts of the same length, clamp a stop block to the table fence. Cut panels 1/4 in. short of the measured width. Caution: Wear hearing and eye protection.
Note: You can download and print Figure B from the Additional Information section below.