Trestlewood II "Salty Fir" Weathered C-S Timbers

Trestlewood II "Salty Fir" Weathered C-S Timbers

Specification Sheet #1103 - Trestlewood II Weathered Timbers

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Trestlewood II Salty Fir Weathered

Specification Sheet #1103 - Trestlewood II Weathered Timbers


Douglas Fir


Piling of Lucin Cutoff Railroad Trestle--Great Salt Lake


Heart Center (HC)


Some Trestlewood II timbers (especially larger and longer ones) contain a few 1" diameter holes where metal has been removed. Such holes are generally surrounded by streaking black stains.

Moisture Content/Stability

Water saturated (often with significant air drying)


Trestlewood II Weathered timbers are circlesawn and then weathered. The resulting surface is rough like standard circlesawn Trestlewood II, but with gray/brown faces rather than the fresh-sawn faces of standard Trestlewood II timbers.

Standard Dimensions

a) Cross-sections: 8x8 to 10x10; b) Lengths: to 16'; c) Target Dimensions: circle-sawn timbers are targeted at full-sawn dimensions; d) Tolerances: circle-sawn timbers are originally cut to targeted dimensions +/- 1/4"; the weathering process can impact dimensions somewhat.

Available Dimensions

a) Cross-sections: to 14x16; b) Lengths: to 32' (longer lengths may be possible on a case-by-case basis);
c) Target Dimensions: circle-sawn timbers are targeted at full-sawn dimensions for dimensions to 12" and 1/2" nominal dimensions for dimensions over 12"; d) Tolerances: circle-sawn timbers are originally cut to the stated dimensions +/- 1/4"; the weathering process can impact timber dimensions somewhat. Tolerances can be somewhat greater for timbers wider than 12" and/or longer than 20'.


Typically, approximately 4 pounds per board foot


Weathered Trestlewood II timbers can be graded (WLCB or WWPA) upon request. Timbers are graded with exception taken for any holes, notches, etc. Weathered Trestlewood II timbers are often somewhat more rustic / rougher in nature than standard resawn Trestlewood II timbers, which will impact how individual timbers will grade out. It is highly recommended that any Trestlewood II timbers that are to be used in a structural application be graded. It is also recommended that standard size Trestlewood II timbers be used whenever possible. Checking, holes (where metal has been removed) and wane tend to be more pronounced in Trestlewood II timbers wider and/or thicker than 10" than in standard size Trestlewood II timbers. A high moisture content should be assumed when consulting design value tables. See also: "Strength" section of Trestlewood II Features/Issues summary.


Trestlewood II timbers have proven to be stable. Like all wood, undried Trestlewood II will experience some shrinkage and develop seasoning checks as it dries. The drying process also often widens any "prior use checking" associated with Trestlewood II's life of service as railroad trestle piling. Trestlewood II does not, in general, twist or warp as much as green timbers.


Trestlewood contains significant amounts of salt and other minerals (often 20%+ by weight), creating special characteristics and/or considerations like those described in the following items.


The coloring of individual Trestlewood II timbers varies widely, from normal Douglas Fir coloring to color combinations unique to Trestlewood II. Surfacing and finishes impact final timber coloring. Color variations are more noticeable in planed timbers than in circle-sawn or band-sawn timbers.


Certain finishes and glues do not work well with Trestlewood II. Most importantly, DO NOT USE WATER-BASED FINISHES. We tend to favor penetrating oil finishes on Trestlewood II timbers and other non-kiln-dried Trestlewood II products because they allow the wood to breathe, thereby facilitating efficient air drying.

Fire Retardance

Schuller International performed an ASTM E-84 Flame Spread test on a Trestlewood II piling sample in January, 1995. The resulting index value was 16, well below the maximum index value of 25 for a Class I fire retardant. Normal Douglas Fir has a flame spread index of 70 to 100. Only a few wood species have flame spread index values less than 75. Fire retardant treatments are generally necessary to meet Class I (and often to meet Class II.)

Metal Corrosiveness

Trestlewood II can have a corrosive effect on metal fasteners, machinery and saw blades. High grade stainless steel fasteners should be used in lieu of regular steel fasteners, especially in applications involving the likely mixing of Trestlewood II, moisture and oxygen.


Trestlewood II absorbs moisture more readily than typical Douglas Fir. Trestlewood II timbers (especially timbers with air dry time) should be handled, stored and transported carefully to minimize any unnecessary reabsorption of moisture. Trestlewood II products should only be used in humid environments after you have carefully considered Trestlewood II characteristics and the implications of those characteristics for your application.


Wet Trestlewood II timbers often have a Great Salt Lake and/or musty smell to them. This odor is especially strong as wet timbers are being cut or otherwise processed. It tends to become less and less of an issue as timbers are allowed to air dry and are kept dry. Our experience suggests that a Trestlewood II odor is most likely to be noticeable in situations involving moisture or high humidity; limited ventilation / air circulation; and/or uncoated/unsealed Trestlewood II products. We believe the most important step in minimizing Trestlewood II odor issues is to control moisture by facilitating the efficient air drying of non-kiln-dried Trestlewood II products and minimizing any reintroduction of moisture.

Salt Leaching

As moisture is drawn out of Trestlewood II timbers, it brings salt with it. Salt leaching tends to be the most concentrated at knots and timber ends, but can happen anywhere. Air dry time reduces, but does not eliminate, salt leaching. Approaches to salt leaching include sanding and refinishing impacted areas to doing nothing (and letting the salt serve as one of the most visible evidences of the history and reclaimed nature of Trestlewood II timbers.) Salt is more visible on planed timbers than on circle-sawn or band-sawn timbers.

Appearance Variation

Weathered timbers will generally vary in appearance from piece to piece and even within a piece. The weathering (amount, mix of colors, etc) and other characteristics of one face can be substantially different than the weathering and other characteristics of another face. Some weathered timbers are cut from larger weathered timbers, giving them one or more fresh-sawn faces.

Trestlewood sometimes uses one or more "juicing" processes to help fresh-sawn and/or less weathered/aged faces blend in with weathered/aged faces. All else being equal, juicing is more likely to be used in situations where (a) timbers are cut from larger timbers (thereby creating fresh-cut faces); (b) Buyer wants all (or most) faces to look weathered/aged; and/or (c) Buyer desires to increase the consistency of the weathered/aged look from face to face.

Additional Information

See the current Trestlewood II Features/Issues summary for additional information about Trestlewood II characteristics and their practical implications. This summary is for informational purposes only and is not a part of the Trestlewood II timbers specification sheet.