What is a Live-Edge Slab?
Definition of Slab
Hardwood lumber typically has four square edges and is sold in random widths and random lengths. Commercial grading rules may be applied. By contrast, construction, or softwood lumber, is manufactured and sold in specified widths, thicknesses and lengths such as a 2-inches by 4-inches by 8-feet long. The words "slabs" or "live-edge slabs" have become common terminology that has developed in the last few years. These terms refer to pieces of lumber with the irregular edges left on, often with the bark. A square-edge piece of lumber is created by removing the irregular edges from a slab.
Lumber is referred to as softwoods, such as construction lumber, or hardwoods which have applications such as furniture, flooring, cabinets, and millwork. Some hardwoods are lighter and softer than some softwoods. For example, basswood, a hardwood, is much lighter than Southern yellow pine, a softwood. The hardwoods contain numerous species with exceptional beauty. Currently, American black walnut (pictured) is the most popular for slabs. It has rich brown-colored heartwood and white sapwood and many people prefer these natural colors in a slab. Commercial walnut lumber is steamed which makes each piece more uniform in color. I am not aware of anyone steaming slabs. Other poplar species include cherry, hard maple, oak and ash. For details on each species, please refer to the hardwood species publications listed at the bottom of this page.
Size and Weight
Hardwood lumber is sold in quarter-inch increments. Thus "4/4" means a rough, dry board is about 1 inch or 15/16 inches thick and "8/4" is about 1 and 15/16 inches thick. Most slabs are irregular in shape and contain various characteristics such as knots, cross grain, and irregular grain patterns. As this type of material dries, it is prone to warping and twisting. Be sure to select pieces thick enough that they will be uniformly flat when finished. Our larger slabs are mostly 8/4 and that allows the piece to finish up at a minimum of 1 1/2 inches thick, and mostly likely it will be 1 3/4 inches thick.
Walnut weighs 37.9 pounds per cubic foot, cherry 34.6, and the oaks, hickories, maples, and ash are in the 40 to 50 pounds per cubic foot range. These weights can vary greatly. A slab of walnut 2-inches thick, 12 inches wide, and 6 feet long will contain one cubic foot and, thus, weigh about 38 pounds. A table top 2-inches thick, 4-feet wide, and 12-feet long will contain 8 cubic feet and weigh over 300 pounds.
Most consumers want a slab that is at least 12 inches wide, if not over 20 inches in width. For a 20-inch wide slab the log will need to be at least 20 inches inside the bark on the small end. The large end could easily be 26 inches. That is large for a walnut log and most woods-grown trees of this size are going to the large commercial lumber or veneer manufacturers. For the slab market, that leaves woods-grown logs that are not suitable for the commercial industry or urban logs. To obtain the wide widths desired, the log is "live sawn". The sawyer starts on one face and saws piece after piece until he gets to the opposite side of the log. The widest pieces are from the center of the log and these will also have the most character. Pieces that are cut side-by-side can be opened like a book. This is called book matching and results in beautiful patterns. End matching is also possible to achieve longer lengths. We keep our logs intact and numbered so that at least one good book match can be obtained from a log. Book matched slabs are most commonly used for tables to achieve wide surfaces with a beautiful, natural pattern. The narrow outer slabs are good for benches.
Hardwood lumber for interior use is dried to 6 to 8 percent moisture content. Slabs should be at the same moisture content. It is important to make sure that the core of the piece is dry as lumber dries from the surface and 8/4 lumber takes time to dry all of the way through. Thick 8/4 lumber or slabs may take up to a year to dry to the 6 to 8 percent moisture content. Once dried, the material has to be stored in climate-controlled condititions. Lumber or slabs that are just dried outside in prevailing atmospheric conditions is called air dried. Lumber or slabs thought to be dry because they have been "sitting for years in a barn, unheated garage, or damp basement" will commonly be between 12 to 18 percent moisture content and will not be acceptable for interior use. It will likely dry once moved inside and warp, twist or end check.
The unique use of slabs is limited only by your imagination. Typical uses include commercial and residential dining room tables and bar tops, kitchen counter tops, mantles, coffee and sofa tables, computer tables, book shelves, headboards, benches, chairs, or any other application where the natural beauty and uniqueness of each piece of wood is desired. Some people simply choose to put up live- edge slabs as art. One unusual application that I have is seen, is a set of four slabs with brackets mounted horizontally on the wall to serve as a 8-foot by 12-foot wine rack behind a commercial bar.
Machining and Finishing
There is a substantial amount of work to convert a live-edge slab into a finished product. Professional custom woodworkers will generally use a jointer to remove any twist from a board. The piece is then run through a planer to smooth both sides and to produce a uniform piece of the desired thickness. The problem with this approach is that jointers and, to some extent, planners are not wide enough to accommodate the wide widths of many slabs. Another option is to use a wide belt sander. These machines can usually accommodate slabs two-to-three feet wide and sometimes up to four feet. Another option is to use a computer numeric controlled (CNC) router which can be programmed to route the surface of the slab flat. Yet another option is to use one of the new scaled down table-sized routers to flatten the slab. Resourceful woodworkers can also select a fairly uniform flat slab and work it by hand. It takes some hard work but it can be done just like before all of our current automated equipment was developed. I have seen some really nice work done, all with hand tools. Congratulations to you talented woodworkers.
Virtue Hardwoods is a local company that does machining of live-edge slabs that we have worked with quite often. Company owner, Mitch Jozefowski, can be reached by phone at 765-245-3323. Particularly if you are wanting to have live-edge slabs shipped, there can a substantial benefit to have the machining done prior to the slabs being shipped. Virtue Hardwoods is able to ship directly to their customers.
The finish applied to a slab is a matter of personal preference. Many, many options are available. Stains, penetrating wipe on finishes, and surface-forming finishes are all options. Stains are used to change or slightly modify the color of a wood surface and to enhance the grain and other characteristics. Penetrating stains are preferred as they do not leave a surface coating that obscures the natural beauty of the wood. Stains are not a final finish. Stains are not necessary on woods like walnut and cherry where the natural color is generally preferred. Wipe-on finishes are easy to apply and penetrate into the wood without leaving a surface film. Surface coatings probably provide the most protection and are applied by brushing or spraying. These are usually available in satin finish or different degrees of gloss. More recently, consumers have begun finishing slabs from a more artistic viewpoint. They form "rivers" between slab edges filled by colored or clear epoxy. These rivers can be quite elaborate and can contain lights, landscape stones, plastic plants or fish, etc. If you have not used a particular finish before, be sure to try it on some scrap wood first.
The fair value of a slab is a difficult thing to determine. Each one is unique and no published common pricing is available. Some web sites, such as ours, post prices. Most do not. Species such as walnut command a premium price just as standard walnut lumber does. For the more preferred hardwood species, widths over about 20 inches command a premium price, just because the large logs are hard to obtain and handle. On the other hand, a wide slab of soft maple would be relatively common and much less expensive than walnut. Many of the portable-type band mills cannot cut anything over about 24 inches maximum. The slab will not average this width because of the flare or other irregularities in the log that the mill has to reach around. Live-edge slab lumber is also hard to handle as the irregularities are constantly catching on other slabs and the material takes up more room in the air-drying stacks, as well as in the kilns.
On our larger pieces, we calculate the board-foot content from the average width on the face that we think should be used. We use commercial wholesale hardwood lumber prices as a base. Walnut slabs in the 16-to-18 inch width range will be priced at about $8 per board foot. Slabs 20-to-24 inches in width are currently around $10 per board foot. Adjustments are made based on various characteristics of each piece and how well we think the slab will be accepted. Cherry and white hard maple will be about two-thirds the price of walnut. Other species will be roughly one-half the cost of walnut. These board foot prices are similar to what you would pay at a retail lot for square-edge lumber. Unique items such as walnut crotch wood, cross sections, etc., are priced on an individual piece basis.
We prefer not to ship inexpensive slabs as the cost can easily exceed $200 and we need to make arrangements with another party for crating and arranging for the freight. If you find exceptional slabs on our web site and are willing to pay the cost of shipping, please call me at 765-412-6844 and we can discuss options.