What is the best wood for exterior siding?

Thermo wood is considered the best overall choice for modern exterior cladding due to its excellent dimensional stability, low maintenance, and chemical-free production. Ipe is best for maximum durability, while cedar suits traditional designs.

Is thermally modified wood good for exterior siding?

Yes. Thermally modified wood (thermo wood) is specifically designed for exterior applications. The heat treatment process improves decay resistance and dimensional stability, making it ideal for cladding.

How long does wood cladding last?

Lifespan varies by species: thermo wood lasts 25–30+ years, cedar 15–25 years, and ipe 50+ years. Proper installation with ventilation and drainage extends the life of any wood cladding system.

Does wood cladding need a rainscreen?

Yes. A ventilated rainscreen gap behind wood cladding is recommended for all species. This allows moisture to drain and air to circulate, preventing decay and extending the lifespan of the cladding.

What is the most sustainable wood cladding?

Thermo wood from FSC-certified sources is among the most sustainable cladding options. The chemical-free modification process, renewable forestry, and biodegradability at end of life give it strong environmental credentials.

Can wood cladding be used in fire zones?

Ipe (Class A fire rating) is suitable for fire-prone areas. Thermo wood and cedar may require fire-retardant treatment in some jurisdictions. Always check local building codes.

Best Wood for Exterior Cladding in 2025 | Material Guide

Choosing the right wood for exterior cladding affects the appearance, durability, and maintenance cost of your building for decades. This guide compares the top wood species used in modern cladding projects, including thermally modified wood, tropical hardwoods, and traditional softwoods.

Why Wood Cladding?

Wood cladding remains one of the most popular exterior finishing materials worldwide. Its natural warmth, design flexibility, and sustainability credentials make it the preferred choice for architects and homeowners seeking an authentic aesthetic that synthetic materials cannot replicate.

Natural insulation properties improve building energy efficiency
Carbon sequestration — wood stores CO2 throughout its service life
Design versatility with horizontal, vertical, diagonal, and mixed orientations
Can be combined with other materials for contemporary mixed-material facades

Thermo Wood (Thermally Modified Wood)

Thermo wood is produced by heating wood to 180–230°C in a controlled environment, permanently altering its cellular structure. This chemical-free process dramatically improves decay resistance and dimensional stability.

Best for: Residential cladding, commercial facades, soffits, and feature walls

Pros:

Excellent dimensional stability — minimal warping or cupping
Class 1–2 decay resistance without chemicals
Lightweight (Ayous species) for easy installation
Consistent quality and color across boards
FSC/PEFC certified options available

Cons:

Reduced structural strength (not for load-bearing applications)
Can be more brittle than untreated wood

Western Red Cedar

A traditional cladding favorite, western red cedar offers natural beauty and moderate decay resistance from its natural oils.

Best for: Traditional residential cladding, shingle-style homes, rustic designs

Pros:

Beautiful natural grain and warm color
Natural decay and insect resistance
Lightweight and easy to work with
Long track record in North American construction

Cons:

Requires regular staining/sealing (every 2–3 years)
Quality varies significantly by grade
Old-growth supplies diminishing, increasing cost
Shorter lifespan than thermo wood in exterior applications

Planning a decking or cladding project?

Use our material estimator or explore our premium hardwood and thermo wood materials.

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Ipe (Brazilian Walnut)

Ipe is the gold standard for exterior wood applications that demand maximum durability. While primarily known for decking, ipe also makes exceptional cladding.

Best for: High-end residential, commercial facades, coastal environments

Pros:

Janka hardness of 3,680 lbf — extremely durable
Class A fire rating
50+ year lifespan
Natural rot and insect resistance

Cons:

Heavy — requires robust fastening systems
Requires pre-drilling
Higher material cost
Darkens or grays without oil treatment

Material Comparison Table

Factor	Thermo Wood	Cedar	Ipe
Lifespan	25–30+ years	15–25 years	50+ years
Maintenance	Low	Moderate–High	Low
Cost (per sq ft)	$4–$8	$3–$12	$8–$14
Fire Rating	Class B	Class C	Class A
Stability	Excellent	Good	Excellent
Weight	Light	Light	Heavy
Chemical-Free	Yes	Yes	Yes

Installation Considerations

Each material has different installation requirements:

Thermo Wood: Easy to cut and fasten. Available in T&G, shiplap, and channel profiles. Clip systems available for hidden fastening.
Cedar: Easy to work with standard tools. Face-nailing or hidden clips. Allow for seasonal movement.
Ipe: Requires pre-drilling and specialized fasteners. Heavier — ensure substructure can support the weight.

All wood cladding requires proper ventilation behind the boards (rainscreen principle) to prevent moisture buildup and ensure long-term performance.

Conclusion

For most modern cladding projects, thermo wood offers the best balance of durability, aesthetics, sustainability, and cost. Its chemical-free modification process, consistent quality, and low maintenance requirements make it the top choice for architects and builders seeking long-term performance.

For projects where maximum durability is essential, ipe remains unmatched. And for those who prefer a traditional softwood aesthetic, clear-grade cedar delivers timeless beauty — with the understanding that regular maintenance is required.