By The Roofing Brief Team. Last reviewed: October 2026.
How to install metal roofing on a shed comes down to five things done in order: confirm the slope suits an exposed-fastener panel, prep a sound deck or purlins, run underlayment and drip edge, drive gasketed screws where your panel maker’s guide puts them (usually the flats beside the ribs), and cap the ridge over foam closures. A one-slope 8×10 shed is a weekend job for one person with a drill and tin snips. Get the panel squaring and screw placement right and the steel outlasts most shed framing (Union Corrugating backs its painted 2-1/2 inch corrugated panels with a 45-year limited finish warranty). Get them wrong and it leaks at the fasteners within a season.
Shed metal roof decision table: panel, base and fastener by situation
| If your shed has… | Use this | Rule or source |
|---|---|---|
| Slope of 3:12 or steeper | Any exposed-fastener panel: 2-1/2 inch corrugated, Pro-Rib, R-panel or 5V | IRC R905.10.2; Union Corrugating (3:12 minimum) |
| Slope from 1:12 up to 3:12 | 7/8 inch corrugated with tape and lap sealant on every side lap | Metal Sales (1:12 minimum); Midwest Manufacturing (sealant required below 3:12) |
| Slope under 1:12 | A membrane such as EPDM, or sealed standing seam; not exposed-fastener panels | IRC R905.10.2 (1/2:12 floor with lap sealant) |
| Open framing, storage only | 2×4 purlins flat at 24 in on center, no deck or underlayment | Union: panel suits solid deck or open framing |
| Finished interior or stored tools | OSB or plywood deck plus synthetic underlayment to stop condensation drip | Panel maker instructions |
| Old shingle roof that is soft or has 2 layers already | Tear off first | IRC R908.3.1.1 (no recover over 2 or more layers or a deteriorated base) |
| Shed footprint over 200 sq ft | Check permit rules before you reroof; the IRC exempts only one-story detached accessory structures up to 200 sq ft, and many cities set a lower line | IRC R105.2 via PermitsGuide shed permit summary (Aug. 2026) |
Can you put a metal roof on a shed at your slope?
Yes, if the shed slope meets the panel’s minimum. Most exposed-fastener corrugated and ribbed panels, the DIY-friendly choice for a shed, need at least a 3:12 pitch (3 inches of rise per 12 inches of run). Standing seam can go lower, down to 1:12 or even 0.5:12 with sealed seams, but it is not a screw-through DIY panel. Below 3:12 with corrugated panels, water backs up under the laps and finds the screw holes.
A gable or lean-to shed at 3:12 or steeper takes a standard corrugated or R-panel install. Measure your existing pitch before buying panels. If your shed is a low-slope flat-ish design under 3:12, use a low-slope membrane instead of exposed-fastener metal.
| Panel type | Minimum slope | DIY-friendly? | Typical shed use |
|---|---|---|---|
| Corrugated, 2-1/2 in (the common home-center panel) | 3:12 | Yes | Most common shed panel |
| Corrugated, 7/8 in deep | 1:12 (Metal Sales) | Yes | Low-slope sheds and lean-tos |
| R-panel / AG-panel (ribbed) | 3:12 | Yes | Barns and larger sheds |
| 5V-crimp | 3:12 | Yes | Rustic look |
| Standing seam | 1:12 (0.5:12 sealed) | No (specialized tools) | Premium, low-slope sheds |
Sources: the 2021 IRC, Section R905.10.2, sets 3:12 as the minimum for lapped, nonsoldered-seam metal panels without applied lap sealant and 1/2:12 with lap sealant applied per the maker’s instructions. The 3:12 rows match the Metal Sales corrugated sell sheet and the Union Corrugating 2-1/2 in corrugated spec page (24 in coverage, 1/2 in rib, 29 or 26 gauge), and the 1:12 row is from the Metal Sales 7/8 in corrugated product manual (32 or 34-2/3 in coverage). Use the stricter of the code and your panel’s instructions.
What materials and tools do you need for a shed metal roof?
You need panels sized to your slopes, gasketed screws, closures, trim, and a short tool list. For an 8×10 shed with a single slope, budget for roughly 3 to 4 panels at 3 feet coverage width each, plus ridge or wall trim. Buy panels cut to length so each run is one piece from eave to ridge, which eliminates end laps.
- Metal panels: corrugated or ribbed, cut to slope length. Panels cover about 24 to 36 inches wide after the overlap rib.
- Screws: #10 or #12 hex-head self-tapping screws with bonded EPDM rubber washers, 1 to 1.5 inches for wood purlins or decking.
- Underlayment: synthetic felt or a peel-and-stick membrane over solid decking.
- Closures: profile-matched foam or butyl closure strips for the eave and ridge.
- Trim: drip edge, ridge cap, and gable/rake trim.
- Tools: cordless drill with clutch, tin snips or nibbler, tape measure, chalk line, and safety glasses.
Cutting the panels cleanly matters. The Midwest Manufacturing steel panel handling and fastening guide says to cut with shears, tin snips, nibblers or panel shears and not to use a circular saw, whose abrasive blade throws hot metal filings that rust the coating. See our guide on how to cut metal roofing for clean-edge methods that protect the finish.
Worked example: materials for an 8×10 single-slope shed
Take an 8×10 shed with a 4:12 single slope, an 8 ft run and a 10 ft eave. The panel length is 8 ft x 1.054 (the 4:12 slope factor) = 8.43 ft, plus a 1 to 1.5 inch eave overhang, so order 9 ft cut-to-length panels or trim 10 ft stock. The eave width is 120 inches plus about 2 inches of rake overhang per side, or 124 inches.
| Item | Quantity math | Price (Oct. 2026 listing) | Subtotal | Source |
|---|---|---|---|---|
| Pro-Rib steel panel, 36 in coverage x 10 ft | 124 / 36 = 3.4, so 4 panels | $39.17 to $40.41 each | $156.68 to $161.64 | Menards listing |
| Or: 2-1/2 in corrugated, 26 in sheet (24 in coverage) x 10 ft, 29 gauge galvanized | 124 / 24 = 5.2, so 6 panels | $30.99 each | $185.94 | Gabriel Building Supply listing; coverage per Union Corrugating |
| #9 x 1 in metal-to-wood roofing screws with washers | About 22 per Pro-Rib panel (4 field rows x 3, 2 edge rows x 5) plus side-lap and trim screws, about 130 total | $27.58 per bag of 250 | $27.58 | Lowe’s listing |
| 2×4 purlins, flat at 24 in on center | Rows at 0, 24, 48, 72 and 96 in along the 101 in slope, plus a row at the high wall: 6 rows of 10 ft | Local lumber price | Varies | Panel maker span tables |
The Pro-Rib layout needs fewer sheets and fewer side laps (3 instead of 5) because each sheet covers 36 inches instead of 24. Price the closures, drip edge and ridge or high-wall trim for your profile at the same store, since trim is matched to the panel.
Do you need decking, or can panels go on purlins?
Both work on a shed. Exposed-fastener panels are stiff enough to span open framing, so many sheds run panels directly over horizontal wood purlins (2x4s laid flat across the rafters, spaced 24 inches on center). This is the cheapest method and skips decking and underlayment. Solid decking (OSB or plywood) with underlayment costs more but adds rigidity, a moisture layer, and a walkable surface. If your rafters or trusses sit farther apart than a typical shed’s, our purlin guide works through spans and whether to set 2×4 purlins flat or on edge.
Use 2×4 purlins at 24 inches on center for a basic utility shed; Union Corrugating rates its 2-1/2 inch corrugated for solid deck or open framing. Use decking plus underlayment if you want a finished interior, condensation control, or plan to store anything moisture-sensitive. On solid decking, always run underlayment, because bare metal over wood sweats and drips inside. Metal roof condensation is a common shed complaint; our metal roof condensation guide covers the vapor-control fixes. For deck thickness, underlayment and screw length on a solid deck, see our guide to metal roofing over a plywood deck.
How to put a metal roof on a shed, step by step
Work eave to ridge, one panel at a time, keeping every panel square to the first and overhanging the eave by 3/4 inch to 3 inches, the range Midwest Manufacturing gives. Do not walk on installed panels more than necessary, and step only on the flats over a purlin or rafter.
- Inspect and prep the frame. Check rafters and top plates for rot or racking. Sister any soft rafter with a matching board. Measure both diagonals of the roof plane; if they differ, Midwest Manufacturing says to compensate in panel placement rather than expect the panels to run square.
- Add decking or purlins. Fasten OSB decking, or install 2×4 purlins flat across the rafters at 24 inches on center, with one purlin at the eave and one at the ridge.
- Run underlayment (decked roofs). Roll synthetic underlayment from the eave up, overlapping horizontal seams 4 to 6 inches, and staple it down. Skip this only on open-purlin installs.
- Install drip edge at the eave. Nail drip edge along the lower edge every 12 to 16 inches so panel runoff sheds into the gutter or off the edge, not behind the fascia.
- Set eave closure strips. Lay profile-matched foam closures on the eave line so the corrugation gaps are sealed against wind-driven rain and insects.
- Square and fasten the first panel. Start at the end away from the prevailing wind. Overhang the eave by about 1 to 1.5 inches. Check square with a chalk line down the roof, because the first panel sets the line for every panel after it.
- Screw where the maker specifies. Most guides put gasketed screws in the flat pans next to the ribs; a few allow the rib top with a longer screw, so follow the guide for your panel. Space them roughly 12 inches on center at each purlin or rafter line, and 6 to 9 inches on center along the eave and ridge edges.
- Overlap and continue. Lap each next panel over the previous by one full rib, running the lap away from the prevailing wind. Fasten through both layers at the overlap rib; Metal Sales specifies 1/4-14 x 7/8 inch stitch screws at 12 inches on center for its 7/8 inch corrugated side laps.
- Trim gable and rake edges. Snip panels to length at the rake and cap them with gable trim screwed every 12 to 16 inches.
- Set ridge closures and ridge cap. Lay foam closures along both sides of the peak, then screw the ridge cap through the panel high ribs on both slopes with rib-top length screws (2 inch Wood Grip in Midwest Manufacturing’s guide) so the cap seals the peak.
Where do the screws go, and how many?
Screws go where your panel maker’s guide puts them, seated snug but not crushed, at 12 inches on center in the field and 6 to 9 inches on center at edges and laps. Many guides use the flat pan: Fabral’s corrugated instructions say gasketed wood screws should be installed in the flat area of the panel adjacent to the ribs. Others allow the rib top: Midwest Manufacturing’s Pro-Rib guide calls for 2 inch Wood Grip screws on the rib top or 1 inch screws in the flat, with screws at the peak and eave in the flat. A rib-top screw needs the longer length because it has to cross the rib height before it reaches the wood. A typical shed panel run takes 20 to 30 screws.
| Location | Screw spacing | Placement |
|---|---|---|
| Field (mid-panel purlins) | 12 in on center | Flat pan beside rib, or rib top with a longer screw if the maker allows it |
| Eave and ridge edges | 6 to 9 in on center | Flat pan |
| Side laps (rib overlap) | 12 to 18 in on center | Through the overlap rib |
| Ridge cap | Each panel high rib | Through the rib into closure |
Set your drill clutch so the rubber washer compresses flat but does not squeeze out past the screw head; Midwest Manufacturing warns that over-torquing cuts the screw’s withdrawal capacity and under-torquing raises leak risk. An over-driven screw dimples the panel and breaks the seal; an under-driven screw leaves a gap. Both leak, and over-tightening is the single most common DIY mistake.
Can you install metal roofing over an existing shed roof?
You can install metal panels over old shingles or roll roofing on a shed, and it is common because it skips the tear-off. Run purlins or furring strips over the old surface to create a flat, screwable base and an air gap. For a small utility shed the weight and inspection stakes are low, so overlay is usually fine as long as the old roof is a single layer (IRC R908.3.1.1 bars a recover over two or more layers on houses), unlike a house where a tear-off is often the better call.
The tradeoff: you cannot inspect the deck underneath, and any rot keeps spreading under the new metal. IRC R908.3.1.1 also rules out a recover where the existing roof is water soaked or too deteriorated to serve as a base. If the existing shed roof is soft, sagging, or leaking, tear it off first. The overlay-versus-tear-off logic mirrors full-house reroofing, covered in our metal roof installation guide and corrugated metal roofing guide.
Common shed metal roof mistakes to avoid
Four installation errors are common sources of shed metal roof leaks, and all are preventable with the maker’s fastener chart (2 inch screws on rib tops, 1 inch in the flats, per Midwest Manufacturing). Fixing them after the fact means backing out screws and reseating panels, so get them right on the first pass.
- Screws in the wrong spot or at the wrong length. Fasten where your panel guide says, and use the screw length it lists for that spot. A 1 inch screw on a rib top barely reaches the wood, which is why Midwest Manufacturing calls for 2 inch screws there.
- Over-tightening. A crushed washer or dimpled panel breaks the seal. Use the drill clutch and stop when the washer sits flush.
- First panel out of square. If panel one is crooked, every panel after it drifts. Chalk a line and check square before fastening.
- No closures or missing underlayment. Open corrugation gaps at the eave and ridge let in rain, wind, and wasps, and bare metal on decking sweats without underlayment. Metal Sales sells profile-matched closures and tape sealant for exactly these two lines.
Report your slope and panel type at the supplier so the closures match your profile; a foam strip cut for 2-1/2 inch corrugated (1/2 inch deep) will not seal 7/8 inch corrugated, and an R-panel strip will not seal either wave.
Frequently asked questions
What is the minimum slope for a metal roof on a shed?
Exposed-fastener corrugated and ribbed panels, the DIY choice for a shed, need at least a 3:12 pitch, meaning 3 inches of rise per 12 inches of run. Standing seam can go as low as 1:12 or 0.5:12 with sealed seams, but it is not a screw-through DIY panel. Below 3:12 with corrugated panels, water backs up under the laps and leaks at the screws.
Do you screw metal roofing on the ribs or the flats?
Follow the fastening pattern in your panel maker’s guide, because makers differ. Fabral’s corrugated instructions put gasketed wood screws in the flat area next to the ribs, while Midwest Manufacturing’s Pro-Rib guide allows 2 inch screws on the rib top or 1 inch screws in the flat, with eave and peak screws in the flat. Whichever spot your guide uses, match the screw length to it and space field screws about 12 inches on center and edge screws 6 to 9 inches on center.
Can you put a metal roof on a shed without decking?
Yes. Exposed-fastener metal panels are stiff enough to span open framing, so many sheds run panels directly over horizontal 2×4 purlins spaced 24 inches on center. This skips decking and underlayment and is the cheapest method. Solid decking with underlayment adds rigidity, condensation control, and a walkable surface but costs more.
Can you install metal roofing over an existing shed roof?
Yes. You can install metal panels over old shingles or roll roofing on a shed by running purlins or furring strips over the old surface to create a flat base and air gap. It skips the tear-off and is common on utility sheds. The tradeoff is you cannot inspect the deck below, so tear off first if the existing roof is soft, sagging, leaking or already has two layers, the limit IRC R908.3.1.1 sets for houses.
How many screws do you need for a shed metal roof?
A typical shed panel run takes 20 to 30 gasketed screws. Space field screws about 12 inches on center at each purlin or rafter line, edge screws at the eave and ridge 6 to 9 inches on center, and side-lap screws through the overlap rib every 12 to 18 inches. Ridge cap screws go through each panel high rib into the closure.
What screws are used for metal roofing on a shed?
Use #10 or #12 hex-head self-tapping screws with bonded EPDM rubber washers, 1 to 1.5 inches long for wood purlins or decking. The rubber washer seals the hole when driven flush. Set the drill clutch so the washer compresses flat without squeezing past the head, because over-tightening breaks the seal and dimples the panel.