Rough, Planed and Finished Lumber Dimensions
Understand how surfacing and machining change the dimensions used for volume.
Dimensions change through processing
Rough lumber retains sawing variation and has not been planed to a uniform finished surface. Surfaced or planed lumber has material removed from faces or edges. Finished parts may be smaller again after jointing, thicknessing, ripping and sanding. A volume statement should identify the stage its dimensions describe.
Nominal thickness classes and product names can persist even after physical dimensions change. The label is not a substitute for measurement when calculating actual solid volume.
Worked thickness change
A rough board measuring 1.125 × 8 inches and 8 feet contains 6 BF. After surfacing to 0.875 × 7.5 inches at the same length, it contains 4.375 BF. The lost 1.625 BF represents removed material in this geometric comparison, not automatically waste charged under a supplier tally.
Planning purchased versus finished yield
A cut list based on finished parts usually understates the rough stock that must be purchased. Defects, straightening, width selection, grain matching and kerf require separate planning. Keep rough purchase volume, process allowance and finished-part volume as distinct figures.
Recording the basis
Write rough, S2S, S3S, S4S or other supplier notation only when its meaning is known in that transaction. Record measured thickness and width for physical volume. If a seller tallies under a trade rule, retain that tally alongside rather than overwriting it with finished dimensions.
Questions about this topic
Does S4S have one universal actual size?
No. Confirm the supplier specification or measure the stock.
Should I price finished dimensions?
Use the basis of the quotation and keep finished yield as a separate planning figure.
Can machining loss be recovered from BF alone?
No. It depends on the starting and ending geometry and process.
Related BoardFoot Bench pages
Method and content reviewed 3 September 2026.