How Much Plywood for a 10x12 Shed Floor?

How that number is worked out

These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.

Floor size compared

The common ten foot wide shed floors. The middle column is what the area divides into before the waste allowance, and the gap between it and the sheet count is what you pay for and cut off.

What else matters here

Five sheets, 90 ft of joist and 2 tubes of adhesive. Twelve is the friendly number in this pair, and it is worth knowing why before choosing a shed size.

Twelve divides by four exactly, so three sheets stood on their four foot edge cover the full 12 ft run with no cut at all. Twelve also equals eight plus four, so sheets laid the long way cover 8 ft and a clean 4 ft strip finishes it, again with no ragged cut. Every dimension that is a multiple of four behaves like this, and almost nothing else does.

Which is the argument for picking shed dimensions off the sheet rather than off a round number. An 8x12 floor and a 10x12 floor are both easy in one direction; a 10x10 is awkward in both. If the shed size is still open, a dimension that is a multiple of four in at least one direction will save cutting, save offcut, and put the joints where they belong without any thought.

What this calculator assumes

• A sheet is 4 by 8, which is 32 square feet, so three and an eighth sheets cover a square.
• Openings come off in full here, not at half. A window hole in a sheathed wall is a real hole and the offcut around it is what the waste line is for.
• The nail count is the fastener schedule rather than a rule of thumb: six inches around every edge and twelve inches into the framing in the field, so a sheet at 16 inch spacing takes 64 nails and one at 24 inch spacing takes 56. Eight penny common runs about 100 nails to the pound.
• Subfloor adhesive is figured on the linear feet of joist under the sheets, at about 84 feet of quarter inch bead from a 28 ounce tube, which is the size subfloor adhesive actually comes in.
• Roof sheathing wants H clips in each bay along the unsupported joint between rafters, which is four per sheet at 24 inches on center. At 16 inches most panel thicknesses do not need them, so the list leaves them off below 19.2 inch spacing.
• A subfloor gets screwed rather than nailed on most jobs, so the list carries the same fastener count in number eight screws at about ninety five to the pound and leaves the nail line under it as the alternative. Only one of those two lines gets bought.
• Thickness does not change the count, only the price and the span rating. Check the panel span rating against your framing spacing before you buy the thin one.

Questions people ask

Other common sizes