By The Roofing Brief Team. Last reviewed: October 2026.
A screw down metal roof is an exposed fastener panel system: the metal panels are fastened straight through the face into the deck or purlins with visible gasketed screws, unlike standing seam, which hides its fasteners under interlocking seams. HomeGuide (November 2025) prices exposed fastener roofs at $500 to $1,200 per square installed, against $900 to $1,600 for hidden fastener standing seam. The trade off is maintenance: Metal Sales specifies about 80 screws per square on its 36 in Classic Rib panel, and every one of them has a rubber washer that sun and thermal movement wear down, so the fasteners need checking on a cycle no other roof demands.
What is a screw down metal roof?
A screw down metal roof (also called an exposed fastener or through fastened roof) attaches each panel to the structure by driving self tapping screws through the panel face and into the roof deck or steel purlins. The screw head sits on top of the metal with a bonded neoprene or EPDM washer that seals the hole. McElroy Metal notes that a washer bonded to the screw head closes the gap between head and washer that a loose washer leaves. Every fastener is visible from the ground, which is the defining feature of the system.
These panels are usually 26 to 29 gauge steel or aluminum, roll formed with ribs for stiffness, and sold in 36 inch net coverage widths cut to length. Metal Sales lists its Classic Rib at 0.63 lb per sq ft in 29 gauge and 0.80 lb in 26 gauge, with a 5 ft minimum and 45 ft maximum recommended length. Because installation needs only a drill, screws, and basic sheet metal tools, it is the entry point for barns, sheds, agricultural buildings, and budget residential roofs. It is also the metal system a DIYer can install with a drill alone, so the fastening steps below matter more than on any other roof.
Screw down vs standing seam metal roof
The choice on almost every metal roof comes down to screw down versus standing seam. On HomeGuide’s figures, screw down costs $5 to $12 per sq ft installed and standing seam $9 to $16, and because exposed fastener panels cover 36 in per sheet against 16 to 18 in for most standing seam, McElroy Metal says they install much more quickly. Screw down fasteners penetrate the panel and need periodic service; standing seam hides its clips, lets the panel move with temperature, and is allowed on much flatter roofs. The table below sets the two side by side.
| Factor | Screw down (exposed fastener) | Standing seam (concealed) | Source |
|---|---|---|---|
| Installed cost | $5 to $12 per sq ft ($500 to $1,200 per square) | $9 to $16 per sq ft ($900 to $1,600 per square) | HomeGuide, Nov 2025 |
| Installed cost, maker estimate | $9 to $12 per sq ft (panels $1.50 to $4.00) | $12 to $16+ per sq ft (panels $4.00 to $7.00+) | Metal America, 2026 |
| Panel coverage | 36 in (Max-Rib, R-Panel, Classic Rib); 24 in (5V) | 12 to 24 in (138T/238T); 13 in (Instaloc) | McElroy and Metal Sales spec pages |
| Fasteners | Screws through the panel face, about 80 per square on 36 in panels | Concealed clips screwed down under the seam | Metal Sales Classic Rib guide; McElroy |
| Code minimum slope | 3:12 without lap sealant; 1/2:12 with lap sealant | 1/4:12 | IRC R905.10.2 |
| Thermal movement | Panel is pinned, so holes can wear into slots | Clips let panels expand and contract | McElroy Metal |
| Longest sensible panel run | Under 40 ft | 40 ft and longer | McElroy Metal |
| Maintenance | Check and tighten or replace screws every 1 to 2 years | Same check, but no exposed screws to replace | HomeGuide maintenance table, Feb 2026 |
| Best for | Barns, sheds, shops, simple roofs at 3:12 or steeper | Homes, long runs, slopes down to 1/4:12 | Editorial guidance from the rows above |
The pinned panel is the hidden weakness. Metal expands and contracts with heat, and because a screw down panel is locked to the deck at every fastener, that movement works against the screw hole instead of a sliding clip. McElroy Metal calls the result slotting: the hole wears into a slot, and once the slot is larger than the washer, water gets in. Its fix is a replacement screw one size larger than the original, and its rule of thumb is standing seam for panel runs of 40 ft or more. For the concealed alternative and how it avoids this, see our guide to hidden fastener metal roofing.
5V metal roof vs standing seam
A 5V crimp panel looks closer to standing seam than corrugated does, but it is still a screw down panel. McElroy’s 5V is 24 in wide with 1/2 in ribs on 12 in centers, needs a solid deck and a 3:12 minimum slope, and lists UL 2218 Class 4 impact and Miami-Dade approval. McElroy’s Instaloc snap lock standing seam, by contrast, is 13 in wide with a 1 in rib, 24 gauge Galvalume, concealed clips and the same 3:12 minimum. If the roof is below 3:12, neither fits without sealant or a mechanically seamed panel. For the full profile breakdown, see our 5V metal roofing guide.
What does a screw down metal roof cost?
A screw down metal roof costs $5 to $12 per square foot installed, or $500 to $1,200 per square, according to HomeGuide’s November 2025 metal roof cost guide. That puts a 2,000 square foot roof at $10,000 to $24,000. HomeGuide lists the material alone at $1 to $5 per sq ft, and panel maker Metal America lists exposed fastener panels at $1.50 to $4.00 per sq ft before labor and $9 to $12 installed.
| Roof size | Screw down at $5 to $12 per sq ft | Standing seam at $9 to $16 per sq ft |
|---|---|---|
| 1,000 sq ft (small home or garage) | $5,000 to $12,000 | $9,000 to $16,000 |
| 1,500 sq ft | $7,500 to $18,000 | $13,500 to $24,000 |
| 2,000 sq ft (average home) | $10,000 to $24,000 | $18,000 to $32,000 |
| 3,000 sq ft (large home) | $15,000 to $36,000 | $27,000 to $48,000 |
| Source | HomeGuide per sq ft range, our arithmetic | HomeGuide per sq ft range, our arithmetic |
Three inputs move a screw down quote. Gauge: ABC Metal Roofing puts a 26 gauge panel at about 15 percent more than 29 gauge in the same profile. Paint: McElroy recommends Kynar 500 (PVDF) over silicone modified polyester (SMP) because SMP shows far more fade and chalk over time, so ask each bidder to price both finishes. Labor: a 9:12 cut up roof takes longer to fasten safely than a 4:12 gable. For how screw down compares across every metal type, see our standing seam metal roof cost guide.
How long does a screw down metal roof last?
HomeGuide puts metal roofs at 30 to 80+ years, and corrugated metal at 30 to 50 years in high-humidity climates, with standing seam lasting longer. The steel panel itself usually outlasts its fasteners: Metal Sales coats unpainted Classic Rib in AZ55 Galvalume and painted panels in AZ50, both per ASTM A792, while the neoprene or EPDM washers under the screws age from UV and thermal cycling long before the metal fails. For how metal compares with other materials, see our roofing material lifespan report.
HomeGuide’s metal roof repair guide (February 2026) schedules structural maintenance every 1 to 2 years at $225 to $1,200, and the first item on that list is checking the fasteners and tightening or replacing them as needed. Washers that crack, screws that back out, and holes that have slotted are the usual failure points, and each one is a potential leak. No panel maker publishes a single re-screw interval, so the roof tells you when: replace any screw with a cracked washer or a slotted hole, using the next size up where the hole has worn.
The re-screwing math most guides skip
The number that decides whether screw down actually saves money is the re-screw cost, and almost no comparison puts it in writing. HomeGuide prices fastener replacement jobs at $150 to $1,000 depending on how many screws are involved. A whole roof is a bigger job: at Metal Sales’ 80 screws per square for 36 in panels, a 2,000 square foot roof (20 squares) carries about 1,600 screws. The table below works through the per year cost with those inputs.
| Line item (2,000 sq ft roof) | Screw down | Standing seam | Source |
|---|---|---|---|
| Installed cost at HomeGuide midpoint | $17,000 ($8.50 per sq ft) | $25,000 ($12.50 per sq ft) | HomeGuide, Nov 2025 |
| Exposed screws on the roof | About 1,600 (20 squares x 80) | None (concealed clips) | Metal Sales Classic Rib guide |
| Screw material for one full re-screw | About $476 (7 packs of 250 at $67.99) | Not applicable | Fasteners Plus #10 x 1-1/2 in, Oct 2026 |
| Scenario A: 30 year life, one re-screw | $17,476 / 30 = about $583 per year | Must last about 43 years to match | Our arithmetic |
| Scenario B: 40 year life, two re-screws | $17,952 / 40 = about $449 per year | Must last about 56 years to match | Our arithmetic |
The table counts screw material only; labor for 1,600 screws is extra, and the routine 1 to 2 year inspection applies to both systems. On these inputs, screw down stays cheaper per year unless standing seam outlasts it by 13 to 16 years, which is plausible inside HomeGuide’s 30 to 80+ year range but not guaranteed. For a barn, rental, or roof you may not own in 15 years, screw down usually pencils out; for a long panel run over 40 ft or a slope under 3:12, standing seam wins on the maker and code rules, not the math.
How to screw down metal roofing correctly
Fastening is the easiest part of a metal roof to do and the easiest part to get wrong. McElroy Metal explains that underdriven screws let water straight in, while overdriven screws seal at first but crack and erode the washer, which is not designed to be compressed that far. The goal is a screw driven straight, seated so the sealing material is just visible at the edge of the washer (the Metal Sales “correct” picture), and placed on the maker’s tested pattern. Follow these steps.
- Use the right screw. Metal Sales calls for a painted or plated screw with a Type A or driller tip and a rubber washer: a #10-14 woodscrew into wood, and a 1/4-14 x 7/8 in stitch screw at side laps on roofs. Lengths of 1 to 1-1/2 in are common for wood decks; steel purlins need a self drilling screw rated for the steel thickness.
- Set the driver, not your wrist. Use a screw gun with the speed and torque setting the fastener maker recommends, which Metal Sales says prevents thread strip-out and coating damage. Push only hard enough to engage the clutch so the drill point does not burn out.
- Drive perpendicular. McElroy Metal requires screws perpendicular to the roof plane, not on an angle. A screw driven at an angle tilts the washer and leaves a gap on one side.
- Seat the washer flush. Tighten until the sealing material is slightly visible at the edge of the washer. If it is not visible, the screw is too loose; if the washer is deformed and pressed past the fastener edge, it is too tight.
- Follow the spacing spec. Metal Sales typically uses 80 screws per square on 3 ft wide panels and 40 per square on 2 ft wide panels, in separate end of panel and field patterns. Its Classic Rib load table shows why support spacing matters: 26 gauge carries 125 psf inward at 2 ft spacing but 32 psf at 4 ft.
- Mark or pre-drill. McElroy says the chalk line is still the tool of choice for hitting the supports. If you pre-drill, sweep the shavings off right away, because they stick to the panel and rust.
Whether to land the screw on the flat of the panel or on the rib changes the seal and the pull strength. Metal America’s install guide puts screws in the flat next to the rib on its exposed fastener panels, while McElroy says there is no single rule because each maker designs and tests its own pattern and fastening order. We compare the placements in where to screw metal roofing, and the screw counts by profile in our metal roof screw pattern chart.
Which panels are screw down panels?
Screw down describes the fastening method, and several common panel profiles use it. All are exposed fastener panels sold in 26 to 29 gauge, cut to length, and fastened through the face. Knowing the profile helps you order the right screws and trim.
- Corrugated: the classic wavy sheet, the cheapest and most DIY friendly. See our corrugated metal roofing guide for sizing and cost.
- PBR and R panel: trapezoidal ribbed panels with 1-1/4 in ribs on 12 in centers (McElroy R-Panel), stiffer than corrugated and rated for open framing. See our R panel roofing guide.
- U panel: a lower rib version of R panel used on lighter structures.
- 5V crimp: smooth panels with V ribs, 24 in wide on McElroy’s version, installed over a solid deck only.
- Ag panel: agricultural grade ribbed panels for barns and outbuildings, the lowest cost tier.
| Panel (maker) | Type | Rib height and spacing | Coverage | Gauges | Minimum slope | Ratings listed | Source |
|---|---|---|---|---|---|---|---|
| Max-Rib (McElroy) | Screw down | 3/4 in, 9 in on center | 36 in | 26 and 29 ga Galvalume; 29 ga G-100 | 1:12 with sealant; 3:12 without | UL 263 Class A, UL 580 Class 90, UL 2218 Class 4 | McElroy Max-Rib |
| R-Panel (McElroy) | Screw down | 1-1/4 in, 12 in on center | 36 in | 26 ga Galvalume | 1:12 with sealant; 3:12 without | UL 580 Class 90, UL 2218 Class 4, Miami-Dade | McElroy R-Panel |
| 5V (McElroy) | Screw down | 1/2 in, 12 in on center | 24 in | 26 ga Galvalume; 29 ga galvanized bare | 3:12 | UL 263 Class A, UL 2218 Class 4, Miami-Dade | McElroy 5V |
| Classic Rib (Metal Sales) | Screw down | 3/4 in, 9 in on center | 36 in | 29 and 26 ga; 24 ga optional | 3:12 | UL 2218 Class 4, UL 580 Class 90, ICC ESR-2385 | Metal Sales install guide |
| Instaloc (McElroy) | Snap lock standing seam | 1 in, 13 in on center | 13 in | 24 ga Galvalume | 3:12 | UL 580 Class 90, UL 1897, UL 2218 Class 4 | McElroy Instaloc |
| 138T / 238T (McElroy) | Mechanical seam standing seam | 1-3/8 in / 2-3/8 in | 12 to 18 in / 16 to 24 in | 24 ga Galvalume | 1:12 / 1/2:12 | UL 580 Class 90, UL 2218 Class 4; FM 4471 (238T) | McElroy 138T/238T |
Is there a metal roof without screws?
No metal panel roof goes on without fasteners, but standing seam hides them, which is what “screwless metal roofing” usually means. Snap lock panels such as McElroy Instaloc and mechanically seamed panels such as 138T and 238T hook onto clips that are screwed to the deck under the seam, so no screw head or washer is exposed to the weather. That is also why standing seam can follow the 1/4:12 slope minimum in IRC R905.10.2 while lapped screw down panels cannot. For the trade offs between the two seam types, see our snap lock vs mechanical seam comparison.
When a screw down metal roof is the right call
A screw down metal roof makes sense when up front cost and speed matter more than the longest possible service life. Panel runs under 40 ft, slopes of 3:12 or steeper, and buildings such as barns, sheds, garages and shops fit the system’s limits, while a long eave-to-ridge run, a low slope porch, or a house you plan to keep for 40 years points to standing seam. Use the thresholds below.
| If | Then | Why (source) |
|---|---|---|
| Panel run is 40 ft or longer | Standing seam on clips | McElroy recommends standing seam at 40 ft and over because of slotting |
| Slope is 3:12 or steeper | Screw down is allowed without lap sealant | IRC R905.10.2 |
| Slope is 1/2:12 to under 3:12 | Screw down only with applied lap sealant and a panel rated that low (Max-Rib and R-Panel list 1:12) | IRC R905.10.2; McElroy spec pages |
| Slope is under 1/2:12 | Standing seam only (code floor 1/4:12; 238T lists 1/2:12) | IRC R905.10.2; McElroy 238T |
| Open purlins or girts, no deck | R-Panel or Max-Rib (rated for open framing), not 5V (solid deck only) | McElroy spec pages |
| Hail country | A panel listed to UL 2218 Class 4 (Max-Rib, R-Panel, 5V, Classic Rib) | Maker spec pages |
| Animal confinement building | Galvanized rather than Galvalume | McElroy: Galvalume outperforms galvanized except in animal confinement |
| Color must hold for decades | Kynar 500 (PVDF) rather than SMP | McElroy fade and chalk comparison |
| Budget caps at about $12 per sq ft installed | Screw down | HomeGuide: standing seam starts at $9 and runs to $16 |
If you expect to own the building past 25 years, price standing seam alongside it and run the per year math above with your own quotes, not just the install total. If the budget or the structure points to exposed fastener, the roof will serve well as long as the screws are installed to the maker’s pattern and checked on HomeGuide’s 1 to 2 year cycle. You can compare all the metal options and other systems in our learn about roofing hub.
Frequently asked questions
Is a screw down metal roof any good?
Yes, for the right building. HomeGuide prices exposed fastener roofs at $500 to $1,200 per square installed versus $900 to $1,600 for standing seam, and panels such as McElroy Max-Rib list UL 2218 Class 4 impact and UL 580 Class 90 uplift ratings. The weakness is the roughly 80 exposed screws per square, whose washers need checking every 1 to 2 years. McElroy recommends standing seam once panel runs reach 40 ft.
How long does a screw down metal roof last?
HomeGuide puts corrugated metal at 30 to 50 years in high-humidity climates, with standing seam lasting longer. The panel steel usually outlasts its screws: the rubber washers age from sun and thermal cycling, and expansion can wear the holes into slots, so the roof stays watertight only as long as its fasteners are checked and replaced.
What is the difference between screw down and standing seam?
Screw down panels are fastened through the face with visible screws, about 80 per square on a 36 in panel per Metal Sales, while standing seam hides its clips under raised seams 12 to 24 in apart. HomeGuide prices screw down at $5 to $12 per square foot installed and standing seam at $9 to $16. IRC R905.10.2 lets standing seam go down to 1/4:12, while lapped screw down panels need 3:12, or 1/2:12 with lap sealant.
How often do screws need replacing on a metal roof?
HomeGuide’s maintenance schedule calls for checking the fasteners every 1 to 2 years as part of $225 to $1,200 of structural maintenance, and it prices fastener replacement at $150 to $1,000 depending on the number of screws. No maker publishes one replacement interval; replace any screw with a cracked washer or a slotted hole, using the next size up as McElroy Metal advises.
How much does it cost to screw down a metal roof?
A screw down metal roof costs $5 to $12 per square foot installed, or $500 to $1,200 per square, per HomeGuide (November 2025), which puts a 2,000 square foot roof at $10,000 to $24,000. Panel maker Metal America lists exposed fastener panels at $1.50 to $4.00 per square foot for material and $9 to $12 installed. A 26 gauge panel costs about 15 percent more than 29 gauge, per ABC Metal Roofing.
Do you screw metal roofing in the flat or the rib?
Follow the panel maker’s tested pattern, because no rule covers every panel: McElroy Metal says each system is designed and tested for its own fastener placement and order. Metal America’s install guide puts screws in the flat next to the rib on its exposed fastener panels, and Metal Sales draws separate end of panel and field patterns for Classic Rib.
Is there a metal roof without screws?
Not without fasteners, but standing seam hides them. Snap lock panels such as McElroy Instaloc (1 in rib, 13 in coverage, 24 gauge, 3:12 minimum) and mechanically seamed 138T and 238T panels attach with concealed clips screwed to the deck under the seam, so no screw heads are exposed to the weather.