Best Screws for Ipe, Cumaru and Tropical Hardwood Decking

You paid more for these deck boards than for the framing underneath them. Then the first screw snapped off flush, and there's no clean way to get it out.

We've spent close to 30 years around fasteners and the crews that use them, and we've seen just about every brand on the shelf go into ipe. Some snap. Some cam out. A few hold. For this one we also went through manufacturer pilot hole specs, published density data and hundreds of installer accounts.

Here's which screw to buy, what size hole to drill first, and where the extra money is worth spending.

Every pilot hole figure above is labeled manufacturer spec or field practice, because they carry different weight and you should know which one you're getting. Where a maker doesn't publish a number for tropical hardwood, the table says so rather than guessing.

Best Screws for Ipe Decking and Fencing Away From Salt Water: Eagle Claw #10 304 Stainless Steel Deck Screws

The best screws for ipe decking away from salt water are #10 304 stainless steel deck screws with a star drive, and you drill a pilot hole before every single one. That second part isn't a suggestion. Skip it and you'll spend your afternoon picking snapped shanks out of boards you paid a fortune for.

Ipe fence work takes the same screw. The wood doesn't know which way it's facing.

• Specs: #10 x 2 in., 304 stainless steel, coarse thread, Type 17 point, flat head with nibs, T25 star drive
• Pilot hole: 9/64 in. full depth, countersink 23/64 in. at 90 degrees
• Price: from $24.95, pack sizes up to 1,750 count
• Best for: 1x ipe, cumaru and garapa decking, fence pickets, and any tropical hardwood job over three miles from salt water
• Skip it when: you're fastening 5/4 boards. See the note below

About that length. A 2 in. screw through a 1x board leaves about 1-1/4 in. in the joist, which is what you want. Through a 5/4 board, which measures a full inch, you're down to about 1 in. of bite. The target most builders work to is 1-1/2 in., so on 5/4 stock step up to the 2-1/2 in. screw in the next section rather than settling for the shorter one.

Why Use Eagle Claw #10 304 Stainless Steel Deck Screws for Ipe Decking and Fencing

Because a #10 gives you shank to work with, and in ipe that matters more than it does anywhere else.

You'll see hardwood suppliers point people toward a #7 or #8 for the smaller head, and they're not wrong about how it looks. But stainless steel isn't heat treated the way a hardened coated screw is, so it's torsionally weaker to start with. Put that in a thin shank, drive it into wood five times harder than pine, and something has to give.

One deck builder working in tropical hardwood laid out his whole setup in a single line: a #10 screw, a 5/32 in. pilot hole, a combination countersink bit, and Eagle Claw stainless steel deck screws in a Torx drive. That's the pattern, and it's the same one the manufacturer documentation supports from the other direction.

The flat head with nibs also does something a plain trim head can't. The nibs cut the last bit of the countersink as the head seats, so the head draws down clean instead of stopping proud and shearing.

Best Deck Screw for Inland Ipe

#10 x 2" 304 Grade Stainless Steel Wood Screws

We reach for these on every inland ipe job that comes through the shop, 1x decking and fence pickets alike. Drill your 9/64 in. pilot, countersink it, and the nibs under the flat head clean out the last of the cone so the head pulls down flush instead of stopping proud. One crew we know ran a whole cumaru fence on these and never picked a snapped shank out of a picket.

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Best Screws for Ipe Decking and Fencing Near Salt Water: Eagle Claw #10 316 Stainless Steel Deck Screws

The best screws for ipe decking near salt water are #10 316 stainless steel deck screws, and the whole reason comes down to one element. 316 carries 2 to 3 percent molybdenum. 304 has essentially none. That's what stands between your deck and a rust streak under every screw head.

A builder who works on the North Carolina coast put it about as plainly as it can be put. Everything down there rusts within months unless it's stainless steel, so he builds the cost into the estimate rather than letting anyone talk him out of it.

• Specs: #10 x 2-1/2 in., 316 marine grade stainless steel, coarse thread, Type 17 point, flat head with nibs, T25 star drive
• Pilot hole: 9/64 in. full depth, countersink 23/64 in. at 90 degrees
• Price: from $37.95
• Best for: any tropical hardwood deck within about three miles of salt water, and 5/4 boards anywhere, since 2-1/2 in. is the right length for 1 in. stock
• Skip it when: you're well inland and fastening 1x. The 304 does the same job for less

Why Use Eagle Claw #10 316 Stainless Steel Deck Screws for Ipe Decking and Fencing

The difference between 304 and 316 deck screws is molybdenum, and it decides how the screw handles salt rather than how it handles the wood.

Chlorides attack stainless steel by pitting through the passive layer, and molybdenum is what slows that down. Inland, that extra element buys you nothing you can measure. Within three miles of the water it's the cheapest insurance on the job.

Both grades stop tannin staining equally, so this is a salt decision and nothing else. If you're two hours from the coast and worried about black streaks under the heads, 304 handles it.

The price gap runs about 5 to 6 cents a screw. A 300 square foot deck takes roughly 1,050 screws, so you're looking at something in the region of $60 across the whole job. Near the water, that's not a decision worth agonizing over.

Best 2-1/2 In. Screw for 5/4 Ipe

#10 x 2-1/2" 304 Grade Stainless Steel Deck Screws

We hand these over whenever somebody shows up with 5/4 ipe, because a 2 in. screw leaves you about an inch of bite and that is not enough on a board this expensive. The extra half inch puts you back at the 1-1/2 in. of thread in the joist that builders work to. Same T25 drive and the same flat head with nibs, so nothing changes about how you drill it or how you seat it.

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Best Screws for Ipe Rails, Posts and Fence Framing: Eagle Claw #10 x 3-1/2 in. 305 Stainless Steel Wood Screws

The best screws for ipe rails, posts and fence framing are #10 x 3-1/2 in. 305 stainless steel wood screws. This is a framing screw, not a deck surface screw, and buying it for your boards is a mistake worth heading off.

• Specs: #10 x 3-1/2 in., 305 stainless steel, coarse thread, T25 star drive
• Price: $46.95 per 100, also sold in 350 and 1,000 packs
• Best for: 2x4 rails into 4x4 posts, handrails, fence framing, 4x4 edging
• Skip it when: you're fastening deck boards. It'll punch straight through a 2x joist

Why Use Eagle Claw #10 x 3-1/2 in. 305 Stainless Steel Wood Screws for Ipe Decking and Fencing

Because a rail connection needs depth a deck board doesn't.

Fastening a 2x4 rail into a 4x4 post means getting through 1-1/2 in. of rail before you've engaged anything, and a 2-1/2 in. screw leaves you an inch. On a handrail somebody's going to lean their full weight against, that's not enough. The 3-1/2 in. screw puts 2 in. into the post.

Same pre-drilling rules apply. Ipe posts and rails are the same material as ipe boards, and a long screw in a tight hole snaps just as readily as a short one.

Best Screw for Ipe Rails and Posts

#10 x 3-1/2" 305 Grade Stainless Steel Wood Screws

We drive these into rails and posts, not into deck boards. Getting a 2x4 rail onto a 4x4 post burns 1-1/2 in. before the thread touches anything that matters, and the 3-1/2 in. leaves 2 in. in the post for whoever ends up leaning on that handrail. Pre-drill the post the same way you would a board, and keep the clutch low while the head seats.

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Best Screws for Ipe When You're Pulling Warped Boards Flat: GRK Stainless Steel R4

Named here because builders working in tropical hardwood bring them up constantly, and pretending otherwise wouldn't fool anyone who's spent an evening reading deck forums. We don't carry them.

A deck builder who runs ipe in a freeze and thaw climate uses the 3-1/8 in. GRK stainless steel R4 for exactly one reason. A warped ipe board doesn't cooperate, and a longer screw gives him something to pull against when he's dragging it down onto the joist.

Why Use GRK Stainless Steel R4 for Ipe Decking and Fencing

Because reach is a real advantage on boards that won't lie down, and it's worth knowing when that applies.

On flat 5/4 stock, a 3-1/8 in. screw buys you nothing over a 2-1/2 in. once you've got 1-1/2 in. in the joist. Past that point extra length adds drag through the joist and nothing else. Where it earns its place is a board with a bow in it, where you need the thread engaged deeper before the head starts pulling.

If that's your situation and you'd rather stay with what we carry, the 305 grade in 3-1/2 in. covers the same ground with more length again. Just check what's underneath before you drive it.

Best Screws for Ipe When Cam-Out Is Your Problem: SPAX Hardwood Screws

Named, not carried.

One carpenter went through four brands of small trim-head screws on a single ipe job. His problem wasn't the metal. It was that the drive recess was too small to carry the torque the wood demanded, so the bit kept slipping out of the head, rounding the recess and taking the screw with it. He found the SPAX hardwood line handled it. A second tradesman reports fifteen years on the brand with a handful of broken #8s and nothing else to complain about.

Why Use SPAX Hardwood Screws for Ipe Decking and Fencing

Because cam-out and snapping are the same problem at different stages, and a bigger drive recess is what interrupts it.

Here's the sequence. The bit slips under load, which rounds the recess. A rounded recess grips worse, so you lean harder on the driver. Leaning harder puts more torque through a shank that was already near its limit. The head shears off flush and now you've got a repair instead of a deck.

A larger recess breaks that chain at step one. It's the same reasoning behind running a T25 rather than a T10 or T15 in this material, and it's why we spec T25 across the range and put the bit in the box.

Tips on Choosing the Best Screws for Your Ipe, Cumaru and Tropical Hardwood Decks and Fences

Choose the grade first and the gauge second, then buy the pilot bit at the same time as the screws. In tropical hardwood those aren't two decisions, they're one.

Start With the Grade, Not the Brand

Use stainless steel and nothing below it. 304 or 305 away from salt water, 316 within about three miles of the coast.

Coated and galvanized fasteners stain tropical hardwood black. The tannins in ipe react with iron and moisture, and the mark bleeds into the wood around the head where it can't be sanded out. This isn't a fringe opinion either. One fastener manufacturer's own documentation tells you not to use its own epoxy coated carbon steel or coated 410 products on redwood, cedar or tropical hardwoods with high tannin content. A brand telling you not to buy its cheaper product is worth more than anything we could say on the subject.

Worth separating three brown marks that people all describe as rust, because the fixes are different:

• Tannin staining is the wood reacting with iron in the fastener. Stainless steel stops it
• Tea staining is cosmetic surface discoloration on stainless steel in coastal air. It looks bad and the fastener is fine
• Corrosion is the metal actually failing. That's a grade problem

One voice in the field argues that good quality coated screws won't stain either, and that staining is the only reason stainless steel gets recommended. It's a minority position, and the manufacturer carve-out above is the reason we don't take it.

Go #10, and Match the Length to the Board

Run a #10 in tropical hardwood. For length, 2 in. on 1x, 2-1/2 in. on 5/4, and 3 in. on 2x stock.

The target is about 1-1/2 in. of thread in the joist. Beyond that you're adding drag and nothing else, and a screw that's too long in thin decking punches through the bottom of a 2x joist where you can't see it.

The gauge argument is worth hearing out. Hardwood suppliers recommend #7 and #8 because a smaller head disappears better on an expensive board, and on a perfectly drilled hole they hold fine. Builders who install ipe for a living tend to step up. One put it in six words: it's dense hardwood, use a #10.

Buy the Screw and the Pilot Bit Together

This is the part everyone gets wrong, and it's why screws snap.

Look up a pilot hole size for ipe and you'll find 3/32 in., 7/64 in., 9/64 in. and 5/32 in. all presented as the answer. They aren't contradicting each other. They're describing two different systems, and nobody names them:

• One hole. A single bore through the board sized between the thread root and the outside of the threads, which is what a combination countersink bit cuts. For a #10 the published figure is 9/64 in.
• Two holes. A clearance hole through the board that the threads pass through without gripping, plus a smaller pilot into the joist underneath. That's where 3/32 in. and 7/64 in. come from, paired with a 3/16 in. clearance

Miss the clearance hole in a two-hole system and the threads grab the top board, jack it up off the joist and leave a gap you'll be chasing later.

Both systems land in the same place mathematically. The only manufacturer-published ratio in the category runs 71 to 73 percent of the screw's outside diameter across #7 through #12, and federal lab guidance for dense hardwood puts the pilot at 65 to 85 percent of shank diameter. The rule that falls out of both: drill one 64th larger than the thread root.

Builders arrive at the same answer from the opposite direction. They put calipers on the actual screws they're using, measure the smooth core between the threads, and size the bit to that, because they've learned charts don't account for the batch in their hand.

Field practice runs one size above the manufacturer number, at 5/32 in. for a #10. That's deliberate. They're trading a little holding power for not snapping screws, and on a board that costs what ipe costs, that's a reasonable trade.

Things to keep in mind: before you drill a single hole, put calipers on one screw and measure the core between the threads. Two minutes, and it tells you more than any chart.