S2S and S4S?? What Gives?

This week’s question of the week comes from Skee.
He writes, “In your show dedicated to the lumber store, the nice lady at the counter mentioned some terms you didn’t cover. Specifically, S2S and S4S. Yet another stumbling block for the newbie. Could you demystify these terms as well?”

And here was my reply:
“Hi Skee. I knew someone would nail me with that one. I had plans on including a discussion about that, but didn’t want to make the video any longer than it already was. So, in answer to your question, the S2S designation simply refers to how many sides have been pre-surfaced. So S2S= Surfaced 2 Sides. That means the board has been run through the planer on both sides and the original 1′ board (if you are buying 4/4) will now be 3/4″. Keep in mind, when you purchase this board you will still pay as if you have a full 1″. This is exactly why I like to buy my wood in the roughest form possible. Usually I can get a 1″ board perfectly flat and parallel without going all the way down to 3/4″. So I try to avoid the letting the lumber yard do me any “favors”.

An S4S board is fully surfaced on all 4 sides. This is what you will usually find for sale in the small hardwood section at Home Depot. These boards are really for people who don’t have the equipment or means to plane and surface the materials themselves. And you will pay a very high premium for these boards.

In my experience, most hardwood dealers will sell either S2S or rough lumber. If you walk up and simply order 4/4 alder, you will most likely get S2S. It never hurts to ask for clarification. And if you want the material as rough as possible, be sure to ask if they carry rough stock in the species you are looking for.”

Category: Techniques


  1. Michael Carnright March 21, 2007

    I find this website to be very help in today’s world


    I put in s2s and bam :-)

  2. Steve (http://) November 16, 2007

    You can also add other lumber yard talk like SLR1E, FAS&SEL, B and Better, and the various common grades you can purchase. A discussion on kiln dried vs air dried lumber might be appropriate here too. Gee, should I make this a question of the week?

    As a kid we always had wide, long FAS&SEL boards, and kind of became wood snoobs. In my 20’s when I was in my first teaching career I learned to appreciate all of the marvelous defects that can appear in wood. We made a lot of small projects and the wild grain and knots really added a lot to the projects.

  3. Jed March 15, 2012

    Wait – how can S2S be planed on both faces if one of the edges isn’t jointed? Doesn’t that mean 3 sides need to have been surfaced (if the procedure is to joint a face, joint and edge, then plane the other face)? I thought both faces could not be guaranteed to be parallel if this was not the procedure.


      Hey Jed. Faces can be made flat and parallel independent of the edges. Yes we usually do plane one face, then an edge, then the other face, then the other edge, but that’s only because we are trying to surface the wood on all 4 sides in preparation for our project. To make s2s, all you need to do is joint one face, then send that board through the planer with the jointed face down. When its said and done, you have S2S with two parallel and flat surfaces.

  4. Justin Stokes December 8, 2013

    Thanks Marc! Find myself coming back to your site more and more often.

Leave a reply

XHTML: You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Image Map