Like many crafts, woodworking comes with its own dialect. Some of the language of lumber can be tricky to get used to. But many terms that seem technical – such as S2S or S4S – are actually simple to understand and use as you plan your next woodworking project.
What does S2S, S3S, and S4S lumber mean?
Designations S2S, S3S, and S4S tell you the level of milling that has taken place on a board.
In these terms, the first S means “surfaced” and the second “S” means sides. The number tells you how many sides have been surfaced.
What does “surfaced” mean, when referring to lumber? It means that the board has been milled or planed to create a smooth surface, free of saw marks or rough edges.
What Does S2S Lumber Mean?
“S2S” lumber means “surfaced two sides.” S2S boards have two finished surfaces, usually the widths (faces) of the board opposite each other, with the edges left rough. They are ideal for projects that may have a requirement for variable-width boards.
S2S lumber can be used to exploit a rustic look to the edges, or you could use a bandsaw to follow an uneven, natural shape along the length of the grain. When a project only has one or two finished sides to be visible, and you’re okay with some variance in width and length, S2S lumber is the type to choose.
To use S2S lumber in fine woodworking projects, you’ll need to do some of your own milling or planing in your home or shop.
Where to Use S2S Lumber
S2S is great for construction or structural work. If you like to do a little bit of your own milling, then S2S is a great time-saver over using rough cut lumber. You get to see the figure and grain straight off without the back-breaking work required to take it from rough to finished.
What Does S3S Lumber Mean?
It follows then that S3S lumber has been finished on three sides, with one edge ripped nice and straight. One edge may still be rough cut, but in many woodworking projects, some surfaces are never seen, so S3S becomes a practical and economic choice.
S3S boards give a woodworker the choice of flexibility when it comes to custom widths or shapes. Why pay more for a finished edge that will end up in the off-cuts bin? At North Castle Hardwoods, we offer S3S lumber packs in two grades: clear one face (C1F) and clear two face (C2F) to help you maximize efficiency on your project.
Where to Use S3S Lumber
Shelves and bookcases, which have one face against a wall, are ideal projects for S3S lumber. With one rough edge, adjustments for depth are easy: for example, scribing a shelf to an uneven stone, or a brick-finish wall.
What does S4S Lumber Mean?
S4S lumber has been finished on both faces and both edges, which should mean that the boards have four perfectly square corners. The length and width of the board can vary, of course. S4S lumber is different from a lumber square, where the width and thickness of the board are the same measurement.
S4S is a popular choice among hardwood woodworkers. The lumber is ready for use in a wide range of standard projects and is of a consistent shape and size.
Where to Use S4S Lumber
Dimensional S4S lumber is ready to use with a minimal amount of preparation or work. Use it on furniture and cabinetry projects, or for cutting boards and any fine woodworking project.
If your time is limited, or you don’t have the necessary milling hardware of a planer or jointer, then S4S lumber is the way to go.
Why Can’t You Buy S1S Lumber?
Surfacing just the one side of a board sounds like the economic thing to do if you only want a finish on say the top of a cabinet, or on the face of wall paneling. However, lumber is a natural material that reacts to changes in humidity.
By finishing just the one side, the rate of drying becomes unequal, and the board will likely cup and bow.
Is Big-Box Store S4S Lumber Worth It?
Most of the lumber on the racks at your local DIY store will be S4S milled wood. It’s easier to handle, cleaner to move and set out for customers than rough cut lumber or S2S. The problem is that the transport and storage of much of this low-grade lumber sometimes leaves a lot to be desired.
Oftentimes it has been exposed to humidity, and it has not been stacked properly. This is why it will show up cupped, warped, and twisted. Finding a nice, straight piece of wood with minimal defects can be a challenge, especially if you’re shopping for hardwood species.
The North Castle Difference
At North Castle Hardwoods, we have generations of experience in selecting, seasoning, and milling American lumber. All of the S4S lumber on our racks has been meticulously sorted for quality and stored with utmost care. Call or visit us today to pick out premium S2S, S3S, or S4S hardwood lumber you can rely on.
