# square ft to board feet



## dub560 (Jun 4, 2010)

hey guys, 
i'm having problems converting square ft to bd ft, can you tell me the formula? i would like to install some hardwood in the upstairs of my home but it's going to cost me about five grand. I'm trying to do it myself because it's only about 900 square ft altogether?( i think). so, how much wood do I need to purchase(rough lumber)??? thanks for your help in advance


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## TrBlu (Mar 19, 2011)

A Board Foot is 144 cubic inches. It is the equivalent of 12 inches wide x 12 inches long x 1 inch thick.

Therefore a board that is 2" thick, 12" long and 6" wide is one board foot. 2" x 12" x 6" = 144 cubic inches

The board foot measure is a rough lumber measure. It is the board measured before being plained.

In your example, you would likely use 3/4" thick finished lumber, which was probably 1" unfinished. That would mean 900 bdft would closely cover the space. I highly recommend you allow at least an additional 10% - 30% for cuts, kerfs and scrap.

If you order exactly 900 bdft, I guarantee you will come up short in the end.


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## cabmaker (Sep 16, 2010)

For all practical purposes you will need 900 bd ft to floor 900 sq ft. If buying rough youll be buying nominal one inch material (1 1/8 to 1 1/4 ). If you buy preped material in 3/4 youll be paying for the waste that went to the dust bin. Are you tonge and grooving or what ? Sounds alittle scary when you say your going to try and do it ! Your waste factor will need to be added depending on species, grade, floor layout,etc. Could be nything form 15% to 20%. Good luck with it and charge the hill.


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## longgone (May 5, 2009)

A board foot is a square foot…both have 144 square inches. If your flooring is 4 inches wide then you will need a 36"x4" piece to make the square ft. If you use ther formula of 144 sq inches you can easily calculate by whatever width you select. Simple and easy math. You will probably need to order 10-15% extra because of random lengths that will need to be cut to fit against your wallls.


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## Sawkerf (Dec 31, 2009)

A board foot is 12" x 12" x 1" thick. Since 4/4 lumber is ~1" thick, you'll need 900 sq ft of 4/4. Don't forget to add ~10% to deal with bad spots in the lumber.

Are you sure that you want to DIY the flooring? Unless you're going with basic strip flooring, you're looking at a lot of milling work to make your own. The store bought stuff is already dried and milled. All you gotta do is lay it, sand it, and finish it.


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## jmos (Nov 30, 2011)

The basic formula is 1 BF = 1 ft long x 1ft wide x 1 inch thick. 1 inch thick lumber, or 4/4, is about 1" rough, but only ~3/4" if you buy it S2S or S4S. Different lumber yards have different policies about rounding, but it is usually in their favor. If the board is 5.5" thick, they will probably call it 6" for the BF calc.

For flooring, if you buy pre-made flooring, you'll just be buying by the square foot, not the BF.

If you're going to make the flooring, you'll probably want 3/4" thick stock, so your 900sq ft number would be equal to the BF you'll need in S2S 4/4 stock. You will also need to add something for waste; you'll loose something in length and width milling the stock, and there will be some defects you'll probably want to cut out. For furniture I use 30 to 50% waste. For flooring you might want to estimate less waste.


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## dub560 (Jun 4, 2010)

Well i have this tongue and groove molding set for the table saw and I figure It should be a lot cheaper for me to do it myself(save a few bucks)

_Are you sure that you want to DIY the flooring? Unless you're going with basic strip flooring, you're looking at a lot of milling work to make your own. The store bought stuff is already dried and milled. All you gotta do is lay it, sand it, and finish it._

I might reconsider this journey


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## killerb (Nov 1, 2011)

Figure 50 % over what you want. Doing all that flooring on a table saw and flattening all the stock on a jointer and thickness planing all the stock- that is a lot of time and work. Maybe you want to look at buying the lumber , planed and ripped to size, then take it to a millwork shop and have flooring made. I have made flooring and I have a large shop. Its not as easy as you may be thinking. I can have flooring run for 20 cents a foot if I get the stock to a millwork shop. That is rough sized and square edged. Good luck. bob


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