Square Edge Profiles (S4S, E4E, S1S2E)
These are the building blocks of carpentry. Whether you need smooth trim for a modern window, eased-edge decking for a barefoot-friendly surface, or rough-sawn boards for a rustic look, the profile determines the finish.
S4S (Surfaced 4 Sides)
The Standard Smooth Board.
“S4S” means the board has been planed smooth on all four sides (both faces and both edges). It has crisp, square corners.
Best Uses:
- Interior Trim: Baseboards, casings, and window jambs.
- Cabinetry & Shelving: Where a smooth, furniture-grade finish is required.
- Modern Siding: For a clean, gap-style siding installation.
E4E (Eased 4 Edges)
The Decking Standard.
This is identical to S4S (smooth on all sides), but the sharp 90-degree corners are slightly rounded over (“eased”).
Why It Matters: If you use sharp-cornered S4S for decking, the edges can splinter and feel sharp on bare feet. E4E prevents splinters and creates a soft, finished look between deck boards.
S1S2E (Surfaced 1 Side, 2 Edges)
The Rustic Choice.
This board has one Rough Sawn face (for texture) and one Smooth face (the back). Crucially, the Edges are planed smooth.
Why Not Just Rough Sawn? If you buy “Rough Sawn” lumber, the edges are fuzzy and uneven. They won’t butt together cleanly. S1S2E gives you the rustic texture you want on the face, but the straight, clean edges you need for a tight install.
Dimensions Reference Guide
Don’t get caught by the “Nominal” vs. “Actual” trap. Boards are sold by their rough name (Nominal), but they are milled to a smaller finished size (Actual).
| Nominal Name | Actual Thickness | Actual Width |
|---|---|---|
| 1×4 | 3/4″ | 3-1/2″ |
| 1×6 | 3/4″ | 5-1/2″ |
| 1×8 | 3/4″ | 7-1/4″ |
| 1×10 | 3/4″ | 9-1/4″ |
| 1×12 | 3/4″ | 11-1/4″ |
| 5/4 x 6 (Decking) | 1″ | 5-1/2″ |