Wood Construction Screws

When a job takes a lot of screws into softwood and treated lumber, a deck, a fence, a set of steps, a shed, you want wood construction screws by the bucket. WBC’s #10 softwood construction screws come in 350-count buckets in two lengths. They’re bronze-coated, star-drive flat heads, and they’re made for treated lumber, which is what most outdoor building in Montana is.

What they are

Screw	Size	Length	Count
Bronze softwood screw	#10	2-5/8 in.	350
Bronze softwood screw	#10	3-1/8 in.	350

• #10 is a stout, general-construction size, the size for decks, outdoor projects and heavy-duty work.
• Star drive (a six-point recess) holds the bit tight, so the bit doesn’t cam out and strip the head, which matters when you’re driving hundreds of them.
• Flat head drives down flush, and these production screws cut their own countersink as they seat.
• Coated for treated lumber. Treated lumber is hard on plain steel; these are made to go into it.

Which length

Drive through the thinner piece into the thicker one. As a rule of thumb, about two-thirds of the screw’s length should end up in the piece that’s doing the holding; with thicker lumber you can go a little under that.

• 2-5/8 inch for fastening 5/4 deck boards or 1x fence boards to joists, rails and stringers, where it runs through the board and well into the framing.
• 3-1/8 inch when the top piece is 2x lumber going into deeper framing: 2x decking or stair treads into joists and stringers. A 2x is 1-1/2 inches thick, so the longer screw gets enough thread into the piece below. Two 2x boards laid flat together are only 3 inches thick, so a 3-1/8-inch screw would poke out the back; go shorter there.

Check that the point won’t come out somewhere it shows or catches someone.

Driving them

• Use a bit that fits. A star bit that’s the right size seats deep and won’t slip. A worn or wrong-size bit chews up heads.
• Set the clutch so the head stops flush. Driving past tight strips the threads in the wood or crushes the surface.
• Predrill near the ends of boards, where a screw is most likely to split the wood, and in hard or dry wood.

Where they belong, and where they don’t

These are for ordinary outdoor wood construction in treated lumber and softwood. Two limits:

• Structural connections. Joist hangers, ledger boards, beams and posts carry loads that need fasteners rated for that connection. A general construction screw isn’t a substitute for what the plans or the hanger maker specifies.
• Harsh exposures. Livestock pens and barns, pool areas and spots soaked by corrosive chemicals eat coated screws. For corrals and animal stalls, which see plenty of that across Montana, use stainless fasteners instead.

The Pick

For deck boards and fence boards, the 2-5/8-inch bucket. For 2x decking and stair treads into joists and stringers, the 3-1/8-inch bucket. Stainless for anything livestock lives against.

Frequently Asked Questions

Can I use these screws in pressure-treated lumber?

Yes, they’re made to be compatible with treated lumber. For corrosive spots like livestock areas or pools, step up to stainless.

What length screw for deck boards?

2-5/8 inch for 5/4 deck boards, and 3-1/8 inch for 2x decking, so most of the screw ends up in the joist.

Do I need to predrill?

Near board ends and in hard or dry wood, yes, to keep the board from splitting. Elsewhere, follow the directions on the bucket.

Are these structural screws?

No. Use fasteners rated for structural connections like joist hangers, ledgers and beams, as the plans or the hanger maker specify.