Outdoor wood: a complete guide

Introduction

Choosing the right outdoor wood is key to ensuring durability, beauty and low maintenance. In this extensive guide you will discover:

1. Essential features.
2. Precautions and treatments.
3. 13 species compared.
4. Frequently asked questions for search engine optimization.

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1. Essential characteristics of an outdoor wood

a) Natural durability

Outdoor wood is classified according to its resistance to rot and insect attacks. The most recommended for soil or ground contact are:

• Class 1 (very durable): Teak, Ipe, Cumaru — durability ≥25 years.
• Class 2 (durable): Western Red Cedar, Oak, Iroko — durability between 15-25 years.

b) Dimensional stability

Exposure to weather can cause swelling or contraction. Woods such as ipé, teak and iroko have low variation with humidity.

c) Natural oils and resins of outdoor wood

Teak, cedar and redwood contain substances that repel insects and resist rot without the need for chemical treatments.

d) Density and hardness

Denser woods tend to withstand wear and tear better. For example, the ipe reaches ~1,000 kg/m³, ideal for high-traffic areas: parquet floors, pool areas, stairs, etc.

e) Sustainability of outdoor wood

Choose wood that is FSC certified or comes from managed plantations. Example: Plantation teak has similar yield to natural growth in these applications.

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2. Treatments and precautions

Treatment	Purpose	Typical Frequency
Natural oils (teak, linen, tung)	Nourish, retain moisture, protect without sealing.	1-2 times/year
UV Sealants / Varnishes	Preserve the original tone, block UV rays.	Annual or according to wear
Autoclave (pine, eucalyptus)	Inject preservatives to prevent fungus.	Initial + annual maintenance
Heat-treated/furfurylated	Stabilize wood without chemicals.	No special maintenance
Hardware maintenance	Avoid corrosion by tannins.	Inspection together with wood maintenance

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3. Comparison of 15 outdoor woods

Species	Durability	Stability	Maintenance	Typical use	Remarks
Teak	Class 1	★★★★★	Low	Furniture, decks, nautical	Naturally oiled; Gray patina socket
Ipe	Class 1	★★★★★	Low-Medium	Floors, flooring	Very hard, high wear tools.
Cumaru (jatoba)	Class 1	★★★★★	Half	Decks, Outdoor	Similar to ipe, deep red color
Merbau	Class 1-2	★★★★1/2	Half	Decks, furniture	High strength, good aesthetics.
Western Red Cedar	Class 2	★★★★1/2	Low-medium	Furniture, Coatings	Insect repellent resin.
Iroko	Class 2	★★★★1/2	Half	Decks, structures	Good as an alternative to teak
Oak	Class 2	★★★★1/2	Half	Terraces, doors	Effective water resistance. Requires maintenance.
Sequoia	Class 2	★★★★	Half	Coatings, furniture	Rot resistant. Rare.
Acacia	Class 2	★★★★1/2	Half	Outdoor furniture	Good economic alternative. Hard to find for the individual.
Heat-treated alder	Class 2	★★★★	Low-medium	Cladding, furniture	Chemical-free stability.
Treated eucalyptus	Class 2-3	★★★★	Half	Decks, structures	Economical and sustainable.
Treated pine	Class 2-3	★★★★	Depends on use	Structures, pergolas	Requires preservative maintenance.
Walnut	Class 3	★★★★	Half	Furniture, exterior finishes	Beautiful, requires stain protection and frequent maintenance.
Cherry	Class 3	★★★★	High	Exposed furniture, protected areas	Not recommended for outdoor use

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4. Outdoor wood with less maintenance

• Very low need (natural oils, without frequent sealing): teak, ipe, cumaru, merbau, cedar and redwood.
• Moderate maintenance (annual sealing): iroko, oak, heat-treated alder, acacia, treated eucalyptus.
• Frequent (annual) treatment is required for treated pine, eucalyptus, cherry and walnut.

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5. General precautions for outdoor wood

• Confirm sustainable certification (FSC, plantations).
• Use AISI 316 stainless steel hardware to prevent corrosion by tannins.
• Install with slope and ventilation, preventing the wood from touching the floor permanently.

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6. FAQs – Frequently Asked Questions

What is the best wood for exteriors?

Teak, ipe and cumaru (Class 1) offer exceptional natural durability for flooring or direct contact with the outdoors, resisting weather and wear well.

Does teak need outdoor oil?

It’s not strictly necessary, as teak holds up well on its own, but applying oil helps retain its golden hue and reduce the appearance of the inevitable gray patina over time.

What is the difference between ipe and iroko?

IPE is denser (1 000–1 050 kg/m³) and extremely resistant (Class 1), while iroko is semi-heavy (640–660 kg/m³), less hard (Class 2) but more economical and easier to work with.

Can teak be left untreated?

Yes, it can be left untreated, and it will develop a silvery-gray patina with outdoor exposure, just like IPE.

Does cedar withstand rain without varnish?

Yes, cedar is naturally resilient thanks to its resin, but applying a regular sealant helps maintain its original color and appearance.

What maintenance does the IPE require?

IPE requires very little functional maintenance, although annual sealing is recommended if you want to retain its original color and prevent natural grayish aging.

Is autoclaved pine safe?

Yes, autoclaved pine is safe, especially for exterior structures, as long as the treatment (preservatives) is renewed every year to maintain its protection.

Is tropical wood sustainable?

Yes, as long as it is FSC certified or comes from managed plantations, ensuring responsible exploitation.

How often should a teak deck be sanded and oiled?

It is recommended to sand and oil every 1–2 years, depending on weather exposure and wear and tear.

Which outdoor wood prevents fungi and termites?

Ipe, teak, cumaru and cedar stand out for their natural resistance to fungi and termites.

How to prevent wood from fading to the outside?

Applying varnishes or oils with UV protection and performing regular washes to remove residues and maintain protection.

Is oak wood sun-resistant?

Yes, oak has good UV resistance, although it is improved with a sealant to prevent cracks and maintain its integrity.

What chemical-free treatment is available for outdoor wood?

Heat treating and furfurylating stabilize the wood without adding harmful chemical additives.

What type of screws to use on outdoor wood?

It is recommended to use AISI 316 stainless screws, which prevent corrosion and rust marks on the wood.

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7. Conclusion

To build terraces, decks or garden furniture, the best outdoor wood options are class 1 (teak, ipe, cumaru) due to their high durability.

If you are looking for a balance between beauty, price and maintenance, opt for class 2 woods such as iroko, cedar or oak. Economical or domestic woods (treated pine, cherry, walnut) require frequent treatment and specific care.