What Does S2s Mean
Surfaced on two sides (the two faces, edges left rough)
- S2S = a board planed smooth on both wide faces only
Methodcommon for rough hardwood sold with a clean reference face and back but un-jointed edges, left for the buyer to rip and joint to final width.
Buy S2S stock to a rough width slightly over your final cut width to allow for edge-jointing.
S2S means "surfaced on two sides" — a board planed smooth on its two wide faces, with the edges left rough and un-jointed for the buyer to rip and true up later.
Why this one specifically
Rough hardwood is commonly sold S2S rather than fully surfaced, because leaving the edges untouched lets the buyer decide their own final width — jointing an edge and ripping to width happens as part of dimensioning the specific parts a project needs, not before the board even leaves the mill. That's the opposite priority from construction-grade S4S lumber, which is milled to one exact, universal final size at the mill because virtually every buyer wants the same standard stud dimension regardless of what they're building.
What moves the number
There's no dimension to compute here — S2S describes which faces got surfaced, not a specific thickness or width. The practical consequence is buying width: an S2S board's stated width is its rough, pre-jointed width, so a project needing a true 5" finished part should buy S2S stock at least a little wider than 5" to allow for squaring the edge.