Home / Wood Compare / Spruce-Pine-Fir SPF vs Paulownia
Professional Comparison · Verified Engineering Data · Updated 19 July 2026
Spruce-Pine-Fir SPF VS Paulownia
Which wood is better for your project? Scores are computed from the verified figures on each species page — how we score.
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Spruce-Pine-Fir SPF
26/100 Library Score
🌲Softwood💧Moisture Stable
- Harder wear surface (Janka 510 vs 300 lbf)
- Stronger in bending (MOR 63.0 vs 38.0 MPa)
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Paulownia
14/100 Library Score
🪵Hardwood💧Moisture Stable🌿Sustainable
- Easier to machine and fasten
- Lighter (0.28 vs 0.42 g/cm³)
- Solid choice where its profile fits the project
Visual comparison
Spruce-Pine-Fir SPFPaulownia
Winner by category
There isn't one universally best wood — there's a best wood for each purpose.
| Category | Winner |
|---|---|
| Durability | Tie |
| Stability | Tie |
| Hardness | Spruce-Pine-Fir SPF |
| Strength (MOR) | Spruce-Pine-Fir SPF |
| Stiffness (MOE) | Spruce-Pine-Fir SPF |
| Flame spread | Tie |
| Machining ease | Paulownia |
| Lightness | Paulownia |
Engineering data
| Property | Spruce-Pine-Fir SPF | Paulownia |
|---|---|---|
| Janka Hardness | 510grade lbf | 300WD lbf |
| Density | 0.42grade g/cm³ | 0.28WD g/cm³ |
| MOE | 9.5grade GPa | 4.38WD GPa |
| MOR | 63.0grade MPa | 38.0WD MPa |
| Durability | Class 4 Slightly Durable | Class 4 Slightly Durable |
| Stability | Excellent | Excellent |
| Fire (E84) | Class C indicative | Class C indicative |
| Radial Shrink | 4.4grade % | 2.4WD % |
| Tangential Shrink | 7.4grade % | 3.9WD % |
| T/R Ratio | 1.68 | 1.62 |
Figures carry the same source status as the species pages they come from — verified where cited, indicative where marked.
Best for
| Application | Recommended | Suitability |
|---|---|---|
| Exterior cladding | 🥇 Paulownia | ★★★☆☆ |
| Flooring / wear surfaces | 🥇 Spruce-Pine-Fir SPF | ★★☆☆☆ |
| Furniture / interior joinery | 🥇 Paulownia | ★★★★★ |
| Structural / load-bearing | 🥇 Spruce-Pine-Fir SPF | ★☆☆☆☆ |
Advantages & limitations
Spruce-Pine-Fir SPF
Advantages
- Very low movement in service
- Easy to machine, glue and fasten
- Lightweight — easy handling and installation
Limitations
- Not durable outdoors untreated (Class 4)
- Soft surface — dents under point loads
Paulownia
Advantages
- Very low movement in service
- Easy to machine, glue and fasten
- Lightweight — easy handling and installation
Limitations
- Not durable outdoors untreated (Class 4)
- Soft surface — dents under point loads
Recommendation
Choose Spruce-Pine-Fir SPF if…
- The surface takes traffic or impact
Choose Paulownia if…
- Ease of working and fastening matters
- Weight matters — ceilings, wall panels, transport
- Its profile matches the application better than a single overall score
Frequently asked questions
Which is more durable, Spruce-Pine-Fir SPF or Paulownia?
Neither — both carry the same EN 350 rating (Class 4, Slightly Durable). For outdoor decisions between them, weigh dimensional stability and hardness instead.
Which wood is better for outdoor use?
They are closely matched outdoors — durability and stability come out almost level. Let the application decide: harder surface for decking traffic, lighter weight for cladding.
Is Spruce-Pine-Fir SPF harder than Paulownia?
Yes — Janka 510 lbf vs 300 lbf.
How we score. Each wood gets a weighted composite of the verified figures shown above: durability 22%, stability 18%, hardness 12%, bending strength 12%, machining ease 12%, stiffness 8%, flame spread 8%, lightness 8%. The Library Score is that composite's percentile rank within our 60-species library — 50 means the library median, 90 means it outperforms nine of every ten species we cover. No price data is scored — cost guidance is qualitative. The score summarises the data; it does not replace judgement about your specific application.