Steel Siding Installation: 4 Steps from Bare Wall to Trim
Steel siding installation comes down to four moves. Strip the wall and cover it with a weather barrier. Set the trim and a level starter line. Cut and fasten the panels with the right tools and fasteners. Then flash and finish every opening. Leave room for expansion at each channel, use a metal-rated blade, and never overdrive a fastener. A careful DIYer with a helper can handle a small wall or outbuilding over a few weekends.
The trouble is that steel punishes sloppy work. One rough cut leaves a raw edge that rusts. A crooked starter strip shows on every course above it. If the barrier and flashing are wrong, water gets behind the panels and has nowhere to go, and in the Pacific Northwest that water shows up most of the year. Many guides show panels going up and skip the parts that actually fail.
This guide walks through the whole job in order: tools, underlayment, layout, trim, fastening, and 2026 cost ranges. Legacy Exteriors installs siding on homes around Kirkland, Bellevue, and Redmond, so we also point out where a wall is better handed to a pro.
What to know before you install steel siding
Metal siding installation is a manageable DIY project if you are comfortable on a ladder and with a level, a drill, and metal-cutting tools. It is less forgiving than vinyl. Steel scratches, it cannot be trimmed with a utility knife, and a bad measurement costs you a whole panel. Plan on two people, dry weather, and a slow first course.
Is steel siding hard to install?
The process feels familiar if you have hung vinyl. You set a starter strip at the bottom, hook interlocking panels onto it, and fasten them loosely through a nailing hem. The difference is the material. Steel needs different cutting tools and tighter measuring, and the painted finish scratches easily, so every panel you handle is a small risk. Expect the job to go slower than vinyl.
Know the downsides before you commit. Steel dents from ladders and hail. Rust starts at scratches and raw cut edges if you ignore them. Rain on a metal wall is louder than on most cladding. Condensation can form behind panels when the wall cannot dry, which is why the underlayment in Step 1 matters. Also check with your city before you start. Many jurisdictions require a permit to replace siding, and homes built before 1980 may have lead paint or asbestos-containing materials that need testing before demolition.
Steel forgives nothing at a cut edge, so slow down at every cut and every scratch.
Tools and materials
Gather everything before the first panel goes up, so you never stop mid-course. This is the kit most steel siding installation jobs call for.
Item | What it does |
|---|---|
Steel siding panels | Order about 10% extra for waste and mistakes |
House wrap and seam tape | Weather-resistive barrier over the sheathing |
Flashing tape and drip cap | Seals window and door openings, sheds water |
Starter strip, corner posts, J-channel | Anchor the first course and finish the edges |
Furring strips | Required behind vertical panels, creates a drainage gap |
Corrosion-resistant nails or screws | Screws with neoprene washers for exposed-fastener panels |
Circular saw with metal-cutting blade | Straight cuts through panels and trim |
Nibbler or aviation snips | Notches, curves, and cuts around openings |
4-foot level, chalk line, tape measure | Layout and checking every course |
Touch-up paint from the panel maker | Seals scratches and cut edges |
Gloves, safety glasses, hearing protection | Cut steel edges are sharp, and saws are loud |
Buy trim, fasteners, and touch-up paint from the same manufacturer as the panels. The colors match, and the parts are designed to work together.
What steel siding installation costs
Plan on roughly $7 to $16 per square foot installed in 2026 national averages. Material alone runs about $3 to $8 per square foot, depending on gauge and profile. Gauge is the thickness of the steel, and a lower number means thicker metal. Doing the work yourself removes the labor share, which is the gap between those two ranges.
Scenario (1,500 sq ft of wall) | Per sq ft | Total |
|---|---|---|
DIY, materials only | $3 to $8 | $4,500 to $12,000 |
Professionally installed | $7 to $16 | $10,500 to $24,000 |
Treat these as planning ranges, not bids. Local labor rates in the Seattle area often push quotes toward the high end, and tear-off, rotted sheathing, and extra flashing add to the total. Get a written quote before you decide.
Step 1. Prep the wall and install the weather barrier
Step 1 is to strip the wall to sound sheathing, repair it, and cover it with a weather-resistive barrier, with flashing tape at every opening. Every later step in steel siding installation depends on this layer. If it is wrong, the panels hide a leak that you will not see for years.
Remove old siding and repair the sheathing
Pull off the old siding and inspect what is underneath. Probe the sheathing around windows, corners, and the bottom course with a screwdriver. Soft or dark sheathing means rot, and it must be cut out and replaced with the same thickness of plywood or OSB, nailed to the studs. Check the studs, too, because that is where your fasteners will bite.
Installing over old siding is tempting, but it traps moisture and hides problems. For a wet climate, removal gives the best long-term result.
Never cover a wall you have not inspected, because steel will hide a leak until the damage is expensive.
What to put under metal siding
Cover the sheathing with house wrap or another water-resistive barrier. Start at the bottom and work up, so each upper layer laps over the one below like shingles. Follow the wrap manufacturer's overlap, commonly about 6 inches on horizontal seams. Fasten it flat and tape the seams. This barrier is what actually stops water. The siding only sheds most of it.
Furring strips are the second layer to plan. Vertical panels need horizontal furring or strapping, fastened through the wrap into the studs, usually 16 to 24 inches on center. The strips also create a small air gap behind the panels so the wall can dry, which helps against the condensation problem mentioned earlier. Horizontal lock panels usually fasten directly to the sheathing and studs, but check your manufacturer's instructions.
Flash every window and door
Flash openings in order from the bottom up so water always runs over a lapped layer. Here is the sequence that works:
Apply flashing tape across the sill, extending past both sides.
Tape the two jambs, overlapping the sill tape.
Install a head flashing or drip cap above the opening.
Tape the top flange of the head flashing under the house wrap.
Pay extra attention here. Most siding leaks start at openings, not on open wall.
Step 2. Install trim and snap your layout lines
Step 2 is to install corner posts, J-channel, and the starter strip, then snap lines that keep every panel level or plumb. Metal siding installation shows every layout error, so this stage deserves the most patience.
Set corner posts, J-channel, and drip cap
Install trim before the panels, except where your manufacturer says otherwise. Hang corner posts plumb, checking with a level on both faces. Fasten at the top of each nailing slot and leave the other fasteners centered so the trim can move slightly. Keep about 1/4 inch of space at the bottom of the post and wherever one trim piece meets another.
Run J-channel up both sides and across the top of each window and door. The channel at the head sits on top of the drip cap you installed in Step 1. Miter or notch the corners so water drains out rather than collecting in a pocket. Seal nothing shut. Trim has to drain.
Snap level or plumb lines
Find the lowest point at the base of the wall with a level. Measure up from there to set the top of your starter strip, then snap a chalk line around the house. Foundations are rarely level, so trust the line, not the foundation. Nail or screw the starter strip with its top edge on that line.
Vertical panels need a different layout. Snap a plumb line at the first corner, then measure the wall width and divide by the panel coverage. Take a 25 ft 6 in wall (306 in) and a panel with 16 in of coverage. Hang 18 full panels (288 in), then cut the first and last panels to 9 in each. That beats ending with a 2-inch sliver at one corner.
A starter line off by a quarter inch at the bottom becomes a visible slope by the roofline.
Step 3. Cut and fasten the panels
Step 3 is to cut each panel cleanly and fasten it so the steel can still move. This is the heart of steel siding installation, and fastening technique varies with the panel type.
Cut steel without damaging the finish
Use a circular saw or chop saw fitted with a metal-cutting blade for straight cuts, and a nibbler or aviation snips for notches and curves. A jigsaw tends to leave rough edges. Avoid abrasive cut-off wheels, because the hot particles they throw embed in the paint and rust. Support the panel fully on both sides of the cut, and wear gloves, because cut edges are sharp.
Sweep metal shavings off the panels and the ground immediately. Left on the paint, they rust and leave stains. File any burrs, then dab touch-up paint on every raw edge before the panel goes up.
Hang horizontal lock panels
Hook the bottom lock of the first panel onto the starter strip. Fasten through the slots in the top nailing hem, centered in each slot and left slightly loose so the panel can slide as it expands and contracts. Do not pull a panel tight against the trim. Leave about 1/4 inch at each J-channel.
Work upward course by course. Check level every few courses, not just at the start. Stagger the end joints, keep them out of the main sightlines, and follow your manufacturer's overlap at each splice. Handle panels by the edges so you do not flex or scratch them.
Hang vertical and corrugated panels
Plumb the first panel before you fasten anything. Corrugated and ribbed panels are usually exposed-fastener products. Drive screws with neoprene washers into the flat sections, not the ribs, which avoids leaks and dimpling. Tighten until the washer is snug and slightly compressed, never crushed. Overlap each panel by the rib or corrugation the manufacturer specifies and fasten through both layers.
Panel type | Where to fasten | Rule to follow |
|---|---|---|
Horizontal lock-type | Nailing hem slots into studs | Centered in the slot, left loose |
Concealed-fastener vertical | Clips or flange into furring | Do not pinch the panel tight |
Exposed-fastener corrugated or rib | Screws with neoprene washers in the flats | Snug, never crushed, into furring or studs |
Fasten steel so it can move, because a panel pinned tight will buckle with the first temperature swing.
Step 4. Finish openings, top course, and inspection
Step 4 is to fit panels around every opening, close the top course, seal penetrations, and inspect the whole wall. Metal siding installation can look finished after the last panel and still leak at a vent or a window head, so finish carefully.
Fit panels around windows and doors
Measure each opening twice and cut panels to slide into the J-channel with a 1/4 inch gap for movement. For vertical pieces that run into a bottom channel, use a thin wood shim. Rest the panel on the shim, drive the first screw high enough to hold it, then slide the shim out and reuse it. The panel hangs at the correct height with its expansion gap intact.
Cut small notches with a nibbler rather than forcing a saw into a corner. A saw overcut leaves a gap you cannot repair.
Close the top course and seal penetrations
Cut the top panels to slide under the soffit J-channel or finish trim. If there is no room for a channel, use a utility trim and fasten it as the manufacturer directs. Around hose bibs, vents, and light fixtures, use mounting blocks and flashing. Seal gaps with a sealant rated for painted metal, and keep it off any trim that has to drain.
Final inspection and cleanup
Walk the whole house and check the following:
Panels are level or plumb, with no visible waves.
Fasteners are snug, not crushed, and panels can still move.
Every scratch and cut edge has touch-up paint.
No shavings or debris remain on the panels.
Trim channels drain, and sealant sits only where it belongs.
Rinse the finished wall with water and mild soap. Call a pro instead if the wall is multi-story, the gables are complex, or you found rot you cannot confidently repair.
Finish the wall, or hand off the hard part
Good steel siding installation is mostly patience. You protect the wall with a barrier and flashing, set trim and a true starter line, cut cleanly, fasten loosely, and seal every opening. If those steps are right, the panels will outlast almost any other cladding. If one is wrong, water finds it.
Some walls are better left to a crew, such as tall elevations, complicated gables, or siding that exposes damaged framing. If that sounds like your house, request a free siding quote and inspection from Legacy Exteriors. We lock in your price quote, so there are no surprises when the job is done.
