Sq. Ft. vs. Bd Ft prices

[Sean Troy]

Hi all, I was looking for some rough sawn lumber and found some nice wood but the man selling it was charging by the sq. ft. not bd. ft. I never heard of that. Is this common practice? is there any advantage to buying that way? thanks, Sean

[Lee Schierer]

It's not common, but they are almost the same and less confusing for non-lumber oriented folks. One square foot as you know has no depth or thickness associated with it while a board foot implies that there is a thickness of 1 inch or multiples of 1 " below the surface.

Check the board thickness before you buy and do your calculations in board feet to see if the square foot price is a good deal or not. Remember that rough lumber 12" x 12" x 1" thick will finish up at 11.25" x 12" x .75".

[Gene Howe]

In my experience, Sq. Ft. measures apply to thinner than 3/4" woods. Now, if the guy isn't all that knowledgeable about wood, you may or may not be getting a deal. Measure the thickness(es) first.

[Prashun Patel]

I predict you'll get a million responses that will make this a beaten dead horse.

So let me begin:

For 1" thick stock, sqft = bdft.

[Will Overton]

is a thickness of 1 inch or multiples of 1 " below the surface

Actually it can be any thickness and doesn't have to be multiples of anything.

In inches;

W x L x T / 144 = bf

6 x 144 x 1.666 / 144 = 9.996 bf

[Sean Troy]

Thanks for the help. I'll make sure and check thickness and see if I can get 4/4 out of the wood after planeing at least before deciding. Thanks, Sean

[Frank Drew]

Sean

If the wood is roughsawn, it should have dried to the nominal thickness (4/4, 5/4, whatever), and you'll often luck out and find it a bit thicker. So if the wood is reasonably flat you might not get a full 1" after machining but probably more than 3/4". If it has to dress out at 1" for whatever you're working on, you'll be safer specifying, and paying for, 5/4.

[Chip Lindley]

Originally Posted by Lee Schierer http://sawmillcreek.org/images/buttons/viewpost.gif (http://sawmillcreek.org/showthread.php?p=1492035#post1492035)
is a thickness of 1 inch or multiples of 1 " below the surface


Actually it can be any thickness and doesn't have to be multiples of anything.
In inches;
W x L x T / 144 = bf
6 x 144 x 1.666 / 144 = 9.996 bf

Actually, I beg to differ Will! Lumber is sawed as 4/4, 5/4, 6/4, 8/4, etc. There is enough additional thickness in rough lumber to allow for milling and yield the above finished dimensions. Anything sawed too thin or tapered, to yield 4/4, is usually used to feed the kiln boiler. But, sometimes it is dried anyway, and sold with "shorts" which did not grade.

Doubtful any sawmill operator will calculate thickness as 1.666" Board foot! That is 6/4 lumber. Each 144 sq.in. (sq.ft.) of surface area yields 1.5 bd.ft.

4/4 lumber can be 1-1/8" thick, but you are only charged for 1" thickness, or 1 bd.ft. for every 144" or 1 sq.ft.

To the OP: If the lumber sold by sq.ft. is 2" thick, you may get a heck of a deal! If all is nominally 1" thick, then bd.ft. and sq.ft. will be the same. You will have to know the going price per bd.ft of the species locally, to know if you are getting a deal or not.

[Phillip Ngan]

Lineal feet is a unit of length.
Square feet is a unit of area.
Board feet is a unit of volume.


Square feet and board feet are equal when the lumber is 1" thick (rough). 3/4" milled is usually treated as being the same as 1" rough when calculating board feet.

[Scott T Smith]

And to further complicate things...

Some lumber is sold as "green" measure, which means that it was milled at 5/4 and the dried thickness will be less, but you're paying for the thickness that it was milled at.

Some lumber is sold as "dry" measure, which means that you pay for the exact thickness that you're getting.

Dry measure prices are usually higher per bd ft than green measure prices. The type of measure depends upon the seller - retail stores usually use dry measure, sawmiller operators usually use green measure.

Depending upon the species and type of cut, lumber will dry to different thicknesses. As an example, flat-sawn pecan that is milled at exactly 5/4 green will be about 1-3/16" after kiln drying.

As a comparison, quartersawn oak that is milled at exactly 5/4 green will be around 1-1/16" to 1-1/18" thick after kiln drying.