Black decking screws review: 5 x 40 mm for hardwood

Our verdict point by point

Point	Our verdict
Durability	Good. According to the product data an alloy of stainless steel and steel in C2 grade, stronger than a plain stainless screw, so it is less likely to snap in hardwood.
Appearance	The head is black coated and blends into dark Ipe. You will still see it, in straight lines over each joist.
Installation	Pre-drill every hole with a countersink bit, then screw through the board into the joist. More work than clips.
Maintenance	None. When you oil the deck, just work over the heads.
Price	£29.88 per box, Torx bit included.
Delivery	In stock, delivered in 7 to 14 days.

See the black 5 x 40 mm decking screws

What convinces us

• Made for hardwood. Ipe is hard enough to snap an ordinary screw. This one is stronger than plain stainless and copes with being driven into hardwood again and again.
• Black head. A bright head glints on a dark deck. The black head all but disappears into the timber once the boards are down.
• Torx, not cross head. The bit is less likely to cam out, which saves chewed heads and scratched boards. The bit comes free in the box.
• Right length for thin boards. At 40 mm it is matched to 19 and 21 mm decking boards.

The downsides

• Always pre-drill and countersink. In hardwood a countersunk pilot hole is a must. On a large deck that means hundreds of holes.
• You see the heads. However neat your work, rows of screw heads stay on the deck. For a clean surface, use clips.
• Only the head is black. The shank is bright. You will not see that once the screw is in, but you will in the box.
• One length in this version. 40 mm is not meant for thicker boards. We have longer decking screws for those.

Not sure whether to screw or clip? Call us on +49 2821 7483051.

Who it suits, and who it suits less

A good fit for

• Anyone who wants to face fix 19 or 21 mm hardwood boards on purpose.
• Boards without a side groove, where a clip will not fit.
• A dark deck where the head should barely show.

Less suitable for

• Anyone who does not want to see a single screw head. Choose clips.
• Decking boards thicker than 21 mm.
• Anyone hoping to skip pre-drilling.

Comparison: face fixing or hidden clips

The alternative in our own range is our 21 x 140 mm Ipe decking boards with fixing clips, which is how we prefer to lay a deck ourselves. The black coated stainless steel clip slides into the side groove of the board and is screwed into the joist, so no screw shows on the surface.

	Black decking screw 5 x 40 mm	Hidden clips
On the deck	Rows of black heads	No screws in sight
Which boards	19 and 21 mm, with or without a groove	Boards with a side groove for the clip
Work	Pre-drill and countersink every hole	Slide the clip into the groove and screw it down
Gap	Keep it yourself, we advise 8 mm	8 mm

Our advice: space the joists 40 to 45 cm apart, ideally in Ipe, with weed membrane underneath. If you face fix, keep the screws in a straight line over each joist. It looks far calmer than staggered screws. Prices on 12 November 2026.

Our reviews of the Ipe decking boards and the Ipe decking joists cover the rest of the build.

Frequently asked questions

What screws should I use for hardwood decking?

A screw strong enough for hardwood, such as this C2 grade decking screw. An ordinary screw can snap in Ipe. If you would rather not see any heads, use black coated stainless steel clips.

Do you need to pre-drill decking screws?

Yes. In hardwood you pre-drill every hole with a countersink bit, so the head sits flush and the board does not split.

What length decking screw for 21 mm boards?

This 40 mm screw is made for 19 and 21 mm decking boards. For thicker boards, choose a longer screw.

Work out boards and fixings in the decking calculator

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