Redwood has been a staple of West Coast construction for more than a century, yet builders outside its home region often treat it as a specialty material. Recent industry promotions show that starting to change. At a wholesale lumber tradeshow, a sawmill displayed a full truckload of redwood timbers on the show floor and drew a winner from the attendees to take the load home, part of a campaign to reacquaint the industry with the species. The pitch from mill sales representatives is direct: redwood can be used almost anywhere western red cedar or tropical hardwoods are used, and it performs as well or better in many of the same applications.
That claim is worth testing against the material’s real properties before it goes into a specification. For owners who already work with the species, the practical questions are about upkeep. Redwood that has grayed outdoors can be brought back with the right preparation, using the same sequence of cleaning, sanding, and finishing recommended for restoring weathered redwood siding, and the approach carries over to timbers, posts, and deck boards.
What Makes Redwood a Reliable Building Material
Redwood’s reputation rests on the natural chemistry of its heartwood. The extractives that give the wood its reddish-brown color are the same compounds that resist decay and insect attack. Old-growth redwood is famously durable, with documented service lives measured in decades. Second-growth plantation stock grows faster and contains more sapwood, but it still delivers meaningful resistance when the heartwood percentage is high, which is why grade matters more than the species label alone.
- Natural decay resistance in the heartwood, with extractives that deter fungal growth and termites
- Dimensional stability, so timbers move less with moisture swings than many softwoods
- Low density and weight, which simplify handling, cutting, and fastening on site
- Excellent workability with standard carbide-tipped tools
- Good paint and stain holdout, with a surface that accepts finishes readily
Heartwood vs. Sapwood: What You Are Buying
The proportion of heartwood determines how long a timber lasts, especially in damp conditions. Heartwood is the darker, extractive-rich core of the log. Sapwood is the pale outer band that grew most recently, and it offers little natural protection. A timber sold as heart redwood contains mostly heartwood; a grade that permits sapwood can look identical at a glance while performing very differently in the field. For ground contact and exposed exterior work, specifying heart grades removes the guesswork.
Reading the Grade Stamp
Every bundle should carry a grade stamp from an accredited grading agency. The stamp identifies the mill, the grade, the moisture content at the time of grading, and sometimes the species mix. Learn to read it before accepting delivery. A stamp that reads Construction Heart tells you the piece is suitable for general construction; other grades carry different allowances for knots, checks, and wane.
Condition also changes how the material behaves. A timber that has sat in the weather for a season develops surface checks and gray oxidation, and refinishing goes smoother when you follow the same preparation steps used for cleaning and staining weathered redwood siding, including washing, brightening, and letting the surface dry completely before any coating goes on.
Redwood vs. Western Red Cedar vs. Tropical Hardwoods
Redwood competes directly with western red cedar and with tropical hardwoods for decks, exterior structures, and trim. The three material families overlap in the jobs they can handle, but they differ in weight, cost, stability, and ease of fabrication. The table below summarizes the differences that matter at the plan table and on the jobsite.
| Property | Redwood | Western Red Cedar | Tropical Hardwood |
|---|---|---|---|
| Natural decay resistance | High in heartwood | High | Very high |
| Dimensional stability | Excellent | Good | Varies by species |
| Weight | Light | Light | Heavy |
| Workability | Easy with standard tools | Easy | Dulls tooling quickly |
| Relative cost | Moderate | Moderate | High |
| Supply profile | Plantation and managed forests | Managed forests | Mixed, some contentious sources |
Where Redwood Pulls Ahead
Redwood’s combination of light weight and stability gives it an edge in above-ground work where tropical hardwoods are overkill and cedar is roughly equivalent. It cuts cleanly, holds fasteners well when predrilled, and resists the twisting and cupping that plague other softwoods in wide timbers. The species also finishes well, taking transparent oils and film-forming finishes without the blotching common on some cedars. For a deck, pergola, or exposed timber frame, redwood delivers the appearance of a premium hardwood at a lower cost per board foot.
Project examples from the building press show the range. A detailed build feature on making a memorable redwood arbor walks through post sizing, joinery, and finish selection for an outdoor structure intended to last, and the same detailing principles scale up to porches, carports, and timber-framed additions.
Practical Applications for Redwood Timbers
Redwood timbers earn their keep across the building envelope and around the site. Common applications include:
- Decks and porches, where decking, railings, and structural posts all benefit from the same species
- Pergolas, arbors, and trellises that stay outdoors year-round
- Fences, gates, and privacy screens
- Outdoor furniture, from benches to dining tables
- Structural framing and post-and-beam work, including timber-framed additions
- Siding, fascia, and trim details
Indoors, redwood shows up in ceilings, paneling, and millwork, often paired with other character woods. Many builders combine new redwood with salvaged stock, such as reclaimed barn timbers, for dining tables and mantels where mixed textures are part of the design. That way the project budget concentrates on structural redwood and leaves the decorative pieces to the reclaimed material.
Timber Sizing for Outdoor Structures
Nominal sizes describe rough dimensions; actual sizes run smaller. A nominal 6×6 redwood post measures about 5.5 by 5.5 inches, and a nominal 4×6 timber measures about 3.5 by 5.5 inches. Design loads and spans determine the size you need, so confirm the species’ published design values with the supplier rather than assuming a size from a cedar chart. For posts and beams, specify heart grades and check that all four faces are sound.
Fastener and Connector Notes
Use stainless steel or hot-dipped galvanized fasteners and connectors in exposed exterior redwood. The extractives that protect the wood can corrode plain steel over time, leaving black streaks and weakened connections. Predrill for nails and screws near timber ends to avoid splitting, and size connectors to the actual timber dimensions after surfacing.
Sizing, Grading, and Buying Redwood Timbers
Buying timbers is different from buying dimension lumber. You are ordering by piece count, grade, and moisture content, and the differences show up in price and performance. Moisture content matters most: kiln-dried stock at 15 percent or less moves less after installation than air-dried material, which can shrink and check as it equilibrates indoors.
Site-built landscape structures follow the same buying logic. Projects like building durable steps with landscape timbers depend on consistent sizing and naturally durable or treated stock, because an uneven run of timbers forces shimming and creates trip hazards that no finish will fix.
Estimating How Much You Need
Work through the takeoff in four steps:
- Draw the structure and label every member with nominal size and length
- Tally pieces by size, then add 10 percent for waste, cutting, and defects
- Convert to board feet: nominal width in inches times nominal thickness in inches times length in feet, divided by 12
- Round up to the nearest bundle or truckload quantity
A full truckload is a practical ordering unit for large projects. The load given away at the wholesale tradeshow is roughly what a substantial deck and pergola package consumes, and dealers who order by the truckload typically pay noticeably less per board foot than buyers who order piece by piece.
Common Timber Sizes and Uses
| Nominal size | Actual size | Typical use |
|---|---|---|
| 4×4 | 3.5 x 3.5 in | Posts, railings, furniture |
| 6×6 | 5.5 x 5.5 in | Deck and structure posts |
| 4×6 | 3.5 x 5.5 in | Beams, girders, ledgers |
| 4×8 | 3.5 x 7.25 in | Heavy beams and headers |
Working With Redwood on the Job Site
Redwood machines well, but it rewards a few habits. Keep blades sharp to avoid tear-out on the soft earlywood. Predrill near ends and edges. When cutting freshly milled stock, wear a dust mask and wash up afterward, since the dust can irritate skin and airways. Store timbers off the ground, stickered and covered, so they arrive at the installation point as close to their final moisture content as possible.
On-site milling extends the same material strategy. Contractors with access to logs, whether from a land clearing job or a storm, can turn a fallen tree into lumber with a portable sawmill, producing custom timber sizes that match a project without waiting on a mill order. The economics work best when the log is sound and the volume justifies the setup time.
Finishing and Long-Term Maintenance
Unfinished redwood weathers to a silver-gray, which many owners accept. To keep the warm color, apply a UV-blocking finish soon after installation and renew it on the manufacturer’s schedule. For grayed surfaces, a brightener restores the tone before refinishing. Check fasteners, end grain, and ground-contact points each spring, because those are where decay starts when it starts at all.
Redwood’s renewed push into the market gives specifiers a wider choice of sizes and grades than they had a few years ago. The material performs best when the supply chain is handled with care, from the mill through the yard to the jobsite, and understanding how milling decisions affect quality helps buyers ask the right questions. For anyone considering cutting their own stock, reviewing the key factors for on-site lumber milling clarifies the equipment, log selection, and drying steps involved, and the same diligence that produces good lumber produces good buildings.