Screws for trapezoidal sheet metal
Self-tapping screws for fixing trapezoidal sheet metal to steel and timber substructures, and for joining overlapping sheets. All screws have a hexagonal head (SW 8) and a sealing washer for rain-proof joints. We supply stainless steel versions for outdoor use.
Screws for trapezoidal sheets at a glance
* plus VAT
Fixing screws for steel substructures
To fix trapezoidal sheets to steel sections, use screws with a self-tapping tip. The size of the drill tip depends on the thickness of the substructure.
| Screw | Drill point | Substructure thickness | Application |
|---|---|---|---|
| 7510 | No. 2 | 0.63–3.5 mm | Cold-rolled section beams, thin sections |
| 7520 | No. 3 | 1.5–6.0 mm | Standard steel sections |
| 7530 | No. 5 | 4.0–12.5 mm | Heavy-duty steel beams, IPE sections |
All bolts have a diameter of 5.5 mm and are fitted with a 22 mm washer.
Available lengths:
| Screw | Lengths |
|---|---|
| 7510 | 25, 28, 38, 50, 60, 80 mm |
| 7520 | 26, 32, 34 mm |
| 7530 | 40, 62, 100, 225, 250, 280 mm |
Stainless steel variants for outdoor use:
- 7524 (equivalent to 7520) – A4 stainless steel, lengths: 26, 32, 38, 60 mm
- 7534 (equivalent to 7530) – A4 stainless steel, length: 40 mm
Fixing screws for timber substructure
For trapezoidal sheets on wooden purlins or rafters, use screws with a reduced drill point (No. 1). These pierce the sheet and cut their way into the timber.
| Screw | Diameter | Lengths | Material |
|---|---|---|---|
| 7561 | 4.8 mm | 35 mm | Stainless steel bimetal |
| 7565 | 6.5 mm | 50, 65, 75, 90, 115, 130, 150, 175 mm | Stainless steel bimetal |
Screws 7561 and 7565 are made from stainless steel bimetal and are therefore suitable for both indoor and outdoor use. Both feature a 22 mm sealing washer.
Anchoring depth: At least 7 × screw diameter in the timber. For the 7565 (Ø 6.5 mm), this is therefore at least 45 mm.
Price: 7561 from €44.97 / 100 pieces
Connecting screws for sheet metal overlaps
At the longitudinal and transverse joints of trapezoidal sheets, short screws are used to join the overlapping sheets together.
| Screw | Drill point | Max. sheet thickness | Sealing washer |
|---|---|---|---|
| 7550 | No. 1 (reduced) | 2 × 1.25 mm | 16 mm |
| 7553 | No. 1 with backstitch | from 2 × 1.25 mm | 16 mm |
The 7550 is suitable for thin overlaps, whilst the 7553 with backstitch is suitable for thicker sheet metal stacks.
Available dimensions for the 7550:
- Ø 4.8 × 20 mm
- Ø 5.5 × 22 mm
- Ø 6.3 × 25 mm
- Ø 7.2 × 33 mm
Price: 7550 from €28.83 / 100 pieces | 7553 from €30.05 / 100 pieces
Stainless steel version: 7554 – A4 stainless steel (Ø 4.8 × 20 mm)
Indoors or outdoors – which material?
For trapezoidal sheet metal used outdoors (roofs, façades), use only stainless steel screws. Although carbon steel screws are galvanised, they are not approved for applications exposed to the elements.
| Application | Material | Screws |
|---|---|---|
| Indoor use | Carbon steel (galvanised) | 7510, 7520, 7530, 7550, 7553 |
| Outdoor use | Stainless steel A4 / bimetal | 7524, 7534, 7554, 7561, 7565 |
The stainless steel variants are slightly more expensive, but essential for roofs and façades. For indoor use, you can use the more affordable carbon steel screws.
Which screw for which purpose?
| I want... | Substructure | → Screw |
|---|---|---|
| Fix trapezoidal sheet metal | Steel up to 3.5 mm | 7510 |
| Fastening trapezoidal sheet metal | Steel up to 6.0 mm | 7520 (internal) / 7524 (external) |
| Fastening trapezoidal sheet metal | Steel up to 12.5 mm | 7530 (internal) / 7534 (external) |
| Fastening trapezoidal sheet metal | Timber | 7561 or 7565 |
| Joining sheets | Thin overlap | 7550 (inside) / 7554 (outside) |
| Joining sheet metal | Thick overlap | 7553 |
Installation instructions
Should screws be fitted in the trough or crest of the corrugation?
- Roof: Screw into the trough of the corrugation – rainwater runs off to the side and the sealing washer sits flush against the surface.
- Wall: Screw into the crest of the corrugation – a cleaner finish, no standing water.
Number of screws per square metre:
- Roof surface: approx. 3–4 screws/m² (depending on wind zone)
- Wall surface: approx. 2–3 screws/m²
- Edge and corner areas: increased number due to wind loads
Correct screw fixing:
- Insert the screw at right angles to the surface
- The washer must lie flat – do not overtighten
- Remove drill shavings to prevent surface rust
Overlaps:
- Position connecting screws at intervals of 300 to 500 mm
- Secure both longitudinal and transverse joints
Frequently asked questions about screws for trapezoidal sheets
The length is determined by the sheet thickness plus the penetration depth into the substructure. For steel sections, the screw must protrude at least 3 threads through the steel. For timber, the anchoring depth must be at least 7 times the screw diameter.
No, all our screws are self-tapping. For very thick steel sections (10 mm and above), pre-drilling can make screwing in easier.
No. Sandwich panels are thicker and have an insulating core. There are special screws available for this purpose, with a longer drill tip and a larger sealing washer. You can find these in our ‘Screws for Sandwich Panels’ category.
Yes, the 7550 and 7553 screws are also used for fixing edge profiles and end plates. You will therefore also find them in our ‘Screws for Edge Profiles’ category.
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