Andiroba and cumaru are both South American hardwoods, both classified as durable outdoor timbers, and both positioned as alternatives to ipe in the premium decking market. They are not interchangeable. Understanding where they differ — density, workability, colour, price, and supply chain — will help you choose the right species for your project.
Density and Hardness
Cumaru is one of the densest decking species commercially available. Its Janka hardness is 3,540 lbf and specific gravity runs around 0.94 — it barely floats in water. Andiroba is hard, but in a different league: Janka hardness 1,220–1,430 lbf and specific gravity around 0.62. Both exceed cedar dramatically, but cumaru is roughly 2.5 times harder than andiroba. That density gives cumaru excellent dent resistance underfoot but makes it harder to cut, drill, and fasten.
For decking, cumaru's extreme hardness is both an asset and a challenge. It will not dent under furniture or heavy foot traffic. It requires pre-drilling for every fastener to avoid splitting. Andiroba is more workable — carbide-tipped tools are still recommended, but it behaves more like a high-end domestic hardwood than an ultra-dense tropical species.
Rot Resistance and Durability Class
Both species are rated Durability Class I–II. In practice, cumaru's higher density gives it a slight edge in longevity under sustained moisture exposure — expect 30–50 years for cumaru decking vs. 25–40 years for andiroba in comparable above-ground conditions. Neither requires chemical treatment for outdoor use. See our andiroba durability guide for a full breakdown of andiroba's lifespan factors.
Colour and Appearance
Cumaru is sometimes sold as Brazilian teak, and the resemblance is intentional — it has warm golden-brown tones with fine, straight grain and occasional reddish streaks. It is visually striking and consistent in appearance. Andiroba has a more subdued appearance: medium reddish-brown heartwood, interlocked grain that creates a subtle ribbon figure on quartersawn faces, and a texture that is more variable than cumaru. Both weather to silver-gray if left unfinished.
For a deck where appearance is a primary driver, cumaru's warmer, more uniform colour is often preferred. Andiroba suits projects where durability and value matter more than a premium visual statement.
Price Comparison
Pricing shifts with market conditions and FSC certification requirements, but as of 2026 typical ranges are: cumaru decking $12–$20 per board foot, andiroba $8–$14 per board foot. For a 400-square-foot deck, that difference adds up to $800–$2,400 depending on material thickness and waste factor. Cumaru's density also means it is heavier to handle and ship, which adds to delivered cost.
Sustainability and Supply Chain
Both species can be sourced with FSC certification, though availability varies by supplier and region. Andiroba has an additional sustainability credential: its seeds produce andiroba oil, a significant non-timber forest product in Amazonian communities. Sustainable andiroba forestry supports both timber and oil extraction, creating stronger economic incentives for forest conservation than timber-only operations. Cumaru is well-established in FSC-certified operations but does not carry the same multi-product supply chain dynamic.
Which to Choose
Choose cumaru if you want maximum density and longevity and are comfortable with the additional workability demands and cost. Choose andiroba if you want a highly durable tropical hardwood that is easier to work with and more budget-friendly, and where a 25–40 year outdoor lifespan is more than sufficient. For raised bed and structural garden applications rather than decking, see our overview of andiroba for outdoor garden use.
Frequently Asked Questions
- Is cumaru harder to install than andiroba?
- Yes. Cumaru's extreme density (3,540 lbf Janka) requires pre-drilling every fastener location and dulls saw blades faster. Andiroba at 1,220–1,430 lbf is more workable while still requiring carbide-tipped tooling.
- Which species holds up better near a pool or coastal environment?
- Both perform well in high-moisture environments. Cumaru's higher density gives it a marginal edge in sustained wet conditions, but andiroba's natural oil content makes it a capable choice for poolside or coastal installations.
- Can I mix andiroba and cumaru on the same deck?
- Technically yes, but the significant density difference means they will move differently with seasonal moisture changes. Mixing species on a single deck surface is generally not recommended without consulting a structural designer.
- Which species is more widely available?
- Cumaru has a larger established market in North America and is more consistently available through hardwood decking suppliers. Andiroba is more commonly available through specialty tropical hardwood importers.