Hardwood decking: ipe, cumaru and garapa
Tropical hardwood is the longest-lasting decking sold and the most demanding to install. The boards are twice the weight of cedar, they must be pre-drilled, and the dust is a health hazard rather than an annoyance.
The three species you will be quoted
| Ipe | Cumaru | Garapa | |
|---|---|---|---|
| Density (lb/ft³) | ~69 | ~68 | ~55 |
| Weight, 1×6 × 16 ft | ~46 lb | ~45 lb | ~37 lb |
| Janka hardness | 3,680 | 3,540 | 1,650 |
| Colour | Olive to black, fine grain | Warm brown, orange tint | Pale yellow, greys evenly |
| Material cost per sq ft | $9–16 | $7–13 | $5–9 |
| Fastening | Hidden clip, pre-drilled | Hidden clip, pre-drilled | Hidden clip or face screw |
All three are denser than water at the high end — an ipe board sinks. That single fact drives most of the installation differences below.
Weight changes the job
A 16 ft ipe board weighs about as much as a bag of concrete. Two people can carry it; one person cannot carry it safely on a ladder. On an elevated deck this is the difference between a two-person job and a four-person job with a lift.
It also loads the structure more than the design assumed if the frame was sized for cedar. A 240 sq ft deck in 1×6 ipe adds roughly 900 lb of decking compared with cedar — spread over the joists, usually fine, but worth checking on a long cantilever.
Pre-drilling is not optional
Ipe and cumaru split when a screw is driven without a pilot hole, and the split runs the length of the board. The rule of thumb is a pilot hole 75–80% of the screw's minor diameter, drilled through the board and countersunk for a plug or a clip.
Most installers use stainless clips that hold the board from the edge, which means one screw per clip and two clips per joist crossing. That is roughly 3.5 clips per square foot on a 16″ layout — about 840 clips and 840 pre-drilled holes on a 240 sq ft deck.
The dust is a real hazard
Ipe and cumaru dust is a documented respiratory sensitiser. People who work it without protection develop reactions that get worse with each exposure, and the reaction can become systemic. Cutting outdoors with a respirator is the minimum; a dust extractor on the saw is better.
What you get for the cost
- Life. 30–50 years is realistic, and the material does not need a finish to survive — it greys and keeps going.
- Stability. Very low movement compared with composite or PVC, so tight joints stay tight.
- Appearance. Nothing else looks like it, which is the actual reason most buyers choose it.
What you do not get: a cheap installation. Labour on hardwood runs 30–50% higher than on pine because of pre-drilling and weight, and the clips cost $1.50–3 each. Budget installed cost of $35–60 per square foot.
What this guide does not cover
- Legality and sourcing. Ask for FSC certification; the difference between a legal and an illegal board is paperwork you have to request.
- Finishing schedules. Oiling every year keeps the colour; letting it grey is a legitimate choice, not neglect.
- Structural sizing. The extra dead load is real and this guide does not check your frame.
- Alternatives such as thermally modified ash or domestic black locust, which behave differently again.
Questions people actually ask
Is ipe decking worth the cost?
If the deck is a permanent feature and the look matters, yes — 30 to 50 years with no finish required is a genuine advantage. If you are comparing on first cost, it is roughly three times treated pine installed.
Why does hardwood decking need pre-drilling?
Ipe and cumaru are dense enough that a screw will split the board rather than enter it. A pilot hole 75–80% of the screw's minor diameter prevents the split, and the split would otherwise run the full length of the board.
Does ipe decking need to be oiled?
No, but it will grey within a season if it is not. Oiling once a year keeps the colour; letting it weather to silver-grey does not reduce the lifespan.
Is tropical hardwood decking sustainable?
It can be. Look for FSC-certified stock and ask for the chain-of-custody documentation. The species themselves are not the problem; unmanaged harvesting is.