Black Locust Lumber for sale – Ultimate Guide

Black Locust lumber has become increasingly popular over the last 10 years as the demand for green building has increased. Environmentally conscious architects, engineers and contractors are all trying to appeal to the sustainable markets. Black Locust, also known as Robinia, has become a sought after hardwood product in the design world. 

Traditionally, you could obtain most hardwood lumber at local sources of lumberyards and retail outlets. Nowadays,  E-Bay and other online platforms could be good choices if you are looking for these hardwoods. The best treasures though are found while driving down an old country road. If you see a little handmade sign with “Black Locust Lumber for Sale”, pull in. You may be pleasantly surprised and our grade guide will help you make it a great experience. 

The more traditional ways of obtaining lumber are definitely not the norm, when it comes to procuring Black Locust hardwood. Black Locust or Robinia is now a globally recognized Hardwood resource. Its natural rot resistance, longevity, and non-toxic qualities with no chemicals or oils required, makes this an excellent choice for sustainable projects!

They say the greatest knowledge comes from experience. This article will give you some of my best advice from the past 45 years in the wood industry.

The Nature of the Tree


Trees are nature’s gift to us, just as we as humans are a gift to the world. All trees are significant but there are differences between Black Locust trees and other hardwood species, just as humans are individuals in their own way. Black Locust trees are commonly distinguished as relatively small in diameter. These trees, from the experience of a sawmiller,  will produce a much smaller log. The average length of Black Locust sawlogs falls predominantly into a  range of 8 to 12 feet. Your production becomes more limited in anything longer than 12 feet. It is still possible to produce longer length boards but the challenge then becomes maintaining board quality standards

My best advice when pre-planning your built project, would be to stay within the 8’ through 12’ lengths. This will help you to get the best quality black locust wood possible. This same metric would apply to Black Locust Lumber Decking, Black Locust Lumber Pedestrian Bridges, Rainscreens, Brise Soleil and Black Locust Lumber Siding. Shorter quality boards can be an excellent use for creating Black Locust Site Furnishings for Urban Open Space And Nature Based Playgrounds. I have also utilized these shorter lengths to design our patent pending Proflow Permeable Paver systems that are an excellent sustainable choice for Green rooftop spaces and outdoor landscaping.

Black Locust Lumber board widths should follow these suggested guidelines.  Since these boards are being produced from the smaller diameter sawlogs the ideal widths of black locust boards are between 4” -7” inches. 

 The Black Locust tree is phototropic, which means it grows toward the sun. In nature, this is the Black Locust trees way of survival.  These trees will grow between other majestic hardwoods reaching towards sunlight. As a result, it is not unusual to see very crooked and gnarly branches as these trees will struggle and compete for the most significant sunlight amongst the others. This is why it’s extremely important for you to buy Black Locust from a knowledgeable source. 

You will need to seek viable, experienced wood professionals who understand the availability, the limitations and the quality that is vital for successful outcomes.

The longevity of the sawn Black Locust wood,  with its natural rot resistance, will far surpass the lifespan of the actual Tree.  Compared to other durable woods, with exception to tropical’s,  the lifespan of a sawn Black Locust board can exceed 50+ years. This is the reason many people prefer Black Locust decking because it will rarely need to be replaced. I personally have seen black locust posts that have been in service for over 80 years. This helps to explain black locust lumber prices because you are not replacing your boards every 5-10 years like other woods. 

Meeting the Grade

Grading of Black Locust Lumber, and most hardwood lumber, is classified by the National Hardwood Lumber Association. The NHLA’s  purpose is to establish uniform standards on appearance and grade of hardwood lumber. Black Locust Lumber, with its durability and longevity makes this process unique. The early settlers and the Indigenous peoples of the Americas, they had a saying….” Black Locust was harder than granite!”

With the historical dating proving that black locust wood will last more than 50+ years, makes this saying an understatement!   If you ever tried to drive a nail into a ten year old, Black Locust post, you may believe that the older generations were absolutely correct.

These early lumbermen established the NHLA in 1898, as a lumber grading agency. Their main goal was to create a uniform metric that became the standard as today’s lumber grading rules. That same grading standard was the backbone and growth of furniture manufacturing in the United States. The importance of these grade rules for Black Locust Lumber and other hardwood species allowed distant sawmills and the furniture manufacturers to find a common ground in the buying and selling of hardwood lumber. So if you see black locust lumber for sale be sure to check the grading guidelines before making a purchase.

It is common for a lot of trade jargon to be tossed around. People will use terms such as FAS, Select and 1 Common, 2 Common. It is enough to make your head spin. I don’t want to bore you with a bunch of complex explanations and rules. This will give you a good basic overview to help you in your purchase.

These established grading guidelines were based on a percentage of clear cuttings in a single board. What does the percentage of clear cuttings mean? This term represents how many clear pieces that could be recovered from one single board. Furniture manufacturers, whose primary focus depended heavily on this lumber grading standard, developed this strict metric that set the standard for smaller lumber parts. These parts would ultimately be produced and utilized for the manufacturing of tables and chairs. Although this grading guide works for furniture it should not be applied to Black Locust lumber decking boards for the following reasons.

The NHLA grading rules allow the following characteristics in the clear cutting percentages for all grades and they are therefore, NOT considered defects.

Rot
Wormhole
Unsound knot

In attempting to give a brief and clear summation about grading, here are some of the most common grades that most people are familiar with but may not fully understand.

FAS Lumber Grade

For A Board to be described under NHLA Grade rules it must meet the following requirements. A Board that is 6 inches wide with a minimum length of 8 feet, FAS boards must yield a minimum of 83-1/3%, clear wood cuttings over the entire surface of the board.

Select Grade

Select Grade is virtually the same as FAS, but allows for narrower boards also with a minimum of 83-1/3% of clear wood cuttings also over the entire surface of the board.

1 Common

An unsound knot, a lumberman term for a hole, can be right in the middle of a board and still be called FAS. Can you imagine having a huge whole right in the middle of your deck board? To take it one step further an even larger hole can be in a #1 Common board. In my opinion this is totally unacceptable. When you see what is considered “acceptable” you can quickly understand why I had to come up with my own grade guidelines.

In both examples, there still will be enough of clear cuttings to make the grade. We cannot recall that any of our clients or potential clients would want a new Black Locust Deck that would be littered with holes. Many people who have Black Locust lumber for sale use the NHLA grade guide and the quality of the material does not make the mark. It’s unfortunate for buyers who do not understand the difference. This is why after 45 years in the industry I came up with my own grade guide that has been published and used for over 20 years.

As an innovative company, not an imitator in this Black Locust Lumber industry, we created and further developed our Grade Rules focusing not only the unique characteristics of Black Locust, but for the limitations it has unlike most hardwood trees. My guide is specific only to the Black Locust trees.  These specific rules help to clarify and assist in the purchasing and selling Black Locust wood.  Just as the early Lumberman did in 1898, we have continued to help our clients in making their choices. But, more importantly, it allows us as a manufacturer to maintain quality controls.

The Takeoff

One other trick of the trade is the takeoff. I take great pride in our suggested trim allowance of 3%. Many other producers suggest a trim allowance of upwards of 15%. This allows them to lure you in with a lower board cost but requiring you to purchase much more lumber. The net result, your project costs will be much higher!  Watch out for the cheap price when you meet someone with black locust for sale

As you can see, the NHLA Grade Rules are clearly created for the Furniture Industry. They are not designed for black locust decking, siding and site furnishings. For more examples of Black Locust wood uses please see our portfolio page and the amazing projects we have been apart of over the years.

With that being said, Black Locust lumber does not have a structural grade rule. Black Locust can be used for decks and boardwalks, but it’s not allowed to be used for structural (load bearing) purposes. This is a building code rule. Even though Black Locust Lumber is almost like Steel, there has never been a structural grade rule established by a recognized Lumber Grading Agency. What does this mean? The simple fact is, NO Black Locust Lumber stringers or Black Locust support posts can be utilized for a Black Locust decking application.

As you can see from this article there is much to know when purchasing black locust lumber. Black Locust is an amazing material to work with and finishes to a beautiful smooth surface. The longevity of the wood is a major selling point as well. I hope this article has laid out some of the details that you need to know when sourcing material for your next project.  

So, on your next journey out in the countryside, should you see a road sign for Black Locust Lumber for sale, or you find a potential source of Black Locust Lumber, hopefully you will be a much more informed consumer with understanding some of the most important highlights of the amazing Black Locust tree.

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