Douglas fir or hardwood: Which decking board suits which project?

Those looking to select decking wood often face a fundamental decision: Douglas fir (softwood) or a heavy deciduous wood (hardwood) for the terrace? There is no one-size-fits-all answer. The desired look, processing on the construction site, the weight of the boards, the surface stress, and—where relevant—the available budget are all deciding factors.

It is important to note: The collective term "hardwood" in terrace construction usually refers to dense deciduous wood and does not stand for a single wood species with uniform properties. Garapa, Ipe, Cumaru, and Bangkirai differ in density, hardness, color effect, and processing, among other things. A comparison between Douglas fir and these hardwoods can therefore initially help with the fundamental material decision. Afterward, you can further differentiate between the various deciduous woods.

An overview of the available wood species and designs can be found in our wood decking boards section.

A brief decision-making guide

If you are wondering which wood is suitable for decking boards, you can narrow down the selection based on a few fundamental properties:

• Douglas fir is particularly worth considering if you are looking for a relatively lightweight and easy-to-process softwood. If price is an important selection criterion, the generally lower price level compared to the hardwoods considered here may also speak in favor of Douglas fir.
• Garapa, Ipe, Cumaru, and Bangkirai are dense hardwoods with a significantly higher bulk density than Douglas fir and are correspondingly heavier given the same dimensions and comparable wood moisture. The individual wood species also differ significantly in color, hardness, and processing.
• The desired look can further narrow down the selection: Douglas fir displays a distinct softwood structure, while the deciduous woods considered range from light Garapa to the darker brown tones of Ipe.
• Processing effort and surface hardness should be considered together. The denser and harder deciduous woods place greater demands on cutting and fastening, but at the same time, they possess a noticeably harder surface than Douglas fir.

However, the wood species is only one part of the planning. The board profile, substructure, fastening, drainage, and ventilation must also be coordinated with one another.

Douglas fir decking: Properties, pros and cons

Douglas fir is a softwood and is used for outdoor structures. It is available from both European and North American origins. A Douglas fir decking board should therefore not be broadly classified as "regional" or "German" based solely on the wood species.

Typical is a warm, yellowish-reddish to brown color effect with clearly visible annual rings. Depending on the grading and origin, the proportion of knots, annual ring structure, and color variation can vary. This creates a surface clearly characterized by the natural wood structure.

Due to its lower bulk density, Douglas fir can be sawn and drilled with less tool effort compared to hardwoods like Garapa, Ipe, Cumaru, and Bangkirai. Knots and annual ring structure can influence processing. Especially in the area of board ends and screw connections, pre-drilling can help prevent splitting.

As a softwood, the surface is less hard than that of the hardwoods mentioned. Dents, signs of wear, or minor mechanical damage may therefore be more visible. Whether this is relevant for your material selection depends on the intended use and the desired appearance.

Available profiles and designs can be found under the Douglas fir decking boards section.

What is meant by "hardwood" decking

Botanically, a distinction is made between softwood (like Douglas fir) and hardwood. In decking construction, the term "hardwood" is often used as a collective term for particularly dense, durable deciduous woods (usually from overseas). However, for specific material selection, this classification is too general, as the individual deciduous wood species differ significantly from one another in some cases:

• Garapa: Usually shows a relatively light, yellowish to golden-brown color and has a dense, hard surface.
• Ipe: Is extremely dense and hard, and its color generally falls within the medium- to dark-brown range.
• Cumaru: Also possesses very high density and hardness. The coloring can include yellowish, reddish-brown to darker areas and color streaks.
• Bangkirai: Comprises various species within a wood group in the trade. Yellowish-brown to olive-brown shades are typical; properties and appearance can vary within the group.

Therefore, the term "hardwood decking board" alone does not indicate exactly what kind of look, processing, or material properties to expect, either botanically or technically. If you would like to compare the individual species more closely after making the fundamental decision for a heavy deciduous wood, you can find further information in the hardwood decking board comparison.

Material properties in comparison

Workability

For construction sites with many cuts, connections, or special details, workability can be an important selection criterion. Due to its lower bulk density, Douglas fir—as a softwood—can be sawn and drilled with less tool effort than Garapa, Ipe, Cumaru, and Bangkirai.

The hardwoods mentioned place more strain on tools due to their high density and hardness. Sharp blades, suitable drill bits, and careful preparation of screw connections are therefore particularly important. The specific processing effort differs between the individual wood species.

High hardness is not automatically a quality advantage: it can be a relevant material property for surfaces subject to higher mechanical stress, but at the same time increases the effort involved in cutting and installation.

Weight and handling

Douglas fir has a lower bulk density than Garapa, Ipe, Cumaru, and Bangkirai and is correspondingly lighter given the same dimensions and comparable wood moisture. This is noticeable during transport, cutting to length, and laying.

For balconies, roof terraces, or other structures where the dead weight of the entire structure is relevant, the static situation must be assessed professionally regardless of the wood species.

Look and surface

Douglas fir shows clearly pronounced annual rings and—depending on the grading—a visible knot pattern. This makes the structure typical of softwood clearly recognizable.

The range of visual options is greater with the deciduous woods considered. Garapa, for example, allows for a light, warm surface effect, while Ipe usually appears much darker. Cumaru can show yellowish, reddish-brown to darker areas and color streaks. Bangkirai often falls within the yellowish to medium-brown range.

The surface hardness also differs. Douglas fir is noticeably softer than Garapa, Ipe, Cumaru, and Bangkirai. When selecting, you should therefore not simply distinguish between "softwood" and "hardwood," but also take the desired look and stress into account.

Weathering and color change

Untreated wood surfaces change outdoors under the influence of UV radiation and weather. The original colors fade over time, and the surface develops a gray to silver-gray patina.

This graying is not a quality defect, but a typical visual change in weathered wood surfaces. How quickly and evenly it occurs depends, among other things, on orientation, roofing, and the intensity of weathering. Partially covered areas may therefore gray differently.

In addition, wood-typical changes such as fine surface cracks can occur in outdoor wood. With certain deciduous wood species, ingredients can also be washed out. For adjacent light-colored components, drainage should therefore be considered during the planning stage.

Care

Regardless of the wood species, dirt, leaves, and long-lasting accumulations of moisture should be regularly removed from the terrace. A construction that allows rainwater to run off and the wood to dry out again is also crucial.

Whether a surface is additionally oiled depends primarily on the desired appearance. If you want the original wood color to remain visible for longer, a terrace oil suitable for the respective wood species can be used. Without such treatment, the typical graying develops with weathering.

Even a terrace that is graying untreated should be regularly cleaned and inspected.

Material costs

Douglas fir is usually priced lower than the hardwoods considered here. However, the price level can vary depending on dimensions, profile, grading, origin, availability, and the general market situation.

There is no uniform price level even within the hardwoods. Garapa, Ipe, Cumaru, and Bangkirai can differ from one another in price. If material price is an important selection criterion, the respective available versions should be compared.

Profiles and fastening

In addition to the wood species, the profile influences the effect and processing of a decking board. Smooth, grooved, or otherwise profiled surfaces differ visually as well as in terms of cleaning and maintenance. Side grooves can be part of a planned concealed fastening system.

The choice of profile should therefore be considered together with the type of fastening. Not every fastening system is suitable for every board.

The substructure is equally important. Material, spacing, and fastening must match the selected decking board and the construction. You can learn more about this in the article Choosing a substructure for decking boards.

Overview: Douglas fir vs. deciduous wood / hardwood

Have you already made your fundamental decision? Then you can view the available Douglas fir decking boards directly or compare different wood species and designs via the wood decking boards section. If a dense hardwood is an option, the hardwood comparison will help with further selection.

Which wood species suits which project?

For the decision between Douglas fir or a heavy deciduous wood for the terrace, one should consider which properties are prioritized for the respective application.

• If a relatively lightweight decking wood is required, Douglas fir may be of interest. The lower weight is particularly noticeable during transport, handling, and processing.
• With many cuts or complex connections, the easier processing of Douglas fir can also be a selection criterion. Its lower surface hardness should, however, be taken into account for areas subject to higher mechanical stress.
• If the material price is an important selection criterion, Douglas fir may also be an option, as its price level is usually below that of the hardwoods considered here. The decisive factors are the respective available designs and the current market situation.
• For a light hardwood look, Garapa may be a suitable direction. The yellowish to golden-brown color effect differs significantly from many darker hardwoods.
• For a darker hardwood surface, Ipe may be interesting. The higher weight and more demanding processing should be considered during planning.
• Anyone looking for a very dense hardwood board with a warm and variable color effect can include Cumaru in their selection. The high hardness requires appropriately prepared processing.
• Bangkirai is worth considering if a yellowish to brown hardwood look is desired. Since various species are grouped together under this trade name, the specific product properties and the respective grading should be taken into account.

For balcony and roof terraces, the dead weight of the construction can additionally be relevant. For terraces close to the ground, however, processing, budget, look, and structural details may take precedence.

Regardless of the wood species, the rule applies: sub-surface, substructure, joints, fastening, ventilation, and drainage should be coordinated with the selected decking board and the respective construction.

Conclusion

Whether Douglas fir or a heavy hardwood is the more suitable choice for your patio does not depend on a general ranking of the materials. As a softwood, Douglas fir has a lower bulk density, is lighter, and is easier to work with than Garapa, Ipe, Cumaru, and Bangkirai, requiring less intensive tooling. It is also usually at a lower price point. Its lower surface hardness and pronounced softwood grain should also be taken into account when making your selection.

For hardwoods, further differentiation is required. Garapa, Ipe, Cumaru, and Bangkirai differ in color, density, weight, and processing. Anyone who has decided in principle on a dense hardwood should therefore compare the specific wood species in the next step.

Graying is also not a suitable criterion for rating one group of materials higher than the other: Both Douglas fir and hardwoods change color when exposed to the elements. If you wish to preserve the original color effect for longer, you can adjust your surface care accordingly. Otherwise, the typical gray to silver-gray patina of weathered wood will develop over time.

For your selection, you should therefore first clarify which requirements regarding weight, appearance, processing, surface hardness, maintenance, and—if relevant—budget are most important to you. You can then select the appropriate wooden decking boards by wood species and finish.