Calculating Project Board Footage Usage?

[Scott Hildenbrand]

Anyone have any resources or sites that I can check out that will help calculate the amount of lumber I might need to buy for a project?

Working on the plans for a few projects now and trying to work out the budget sheet to see where my costs are.

Nothing complex. Just working with FAS 4/4 poplar, assuming 20% loss.

Thanks!

[Mitchell Andrus]

Keep in mind that 20bf in 3' long pieces is useless if you're building 4' x 4' bookcases. Likewise, don't buy 8' lengths if you need 5' long parts. The 3' left over is a lot more than your 20% waste allowance.

Calculating board footage is only part of the process.

If you don't do this a lot and aren't likely to use the scraps on another project, ballpark the waste at 35%. This may seem like a lot, but it isn't. Ripping 2, 4" wide parts out of a 10" wide board and having a thin strip left over is about 20% waste when counting the saw kerfs. Cutting a few inches off each end....
.

[Scott Hildenbrand]

I figure the cutlist software that I have will aid in keeping waste down to a minimum.. I'd used it in the past on sheet material, just not rough milled.

I suppose the best thing to do would be to figure out the lumber needed @ +35% and then mill it into usable stock.. THEN run the cutlist software off of the final sizes of stock available?

Just want to make sure that I 1.) Don't cut myself short on materials.. and 2.) Don't end up with piles left over.

Though I can always use what's left.. Have projects of several calibers in the wings.

[David DeCristoforo]

There are several methods for calculating the amount of material needed for a project. The problem is that hardwoods are not generally sold in ideal lengths and widths. Also, the calculations do not account for figure and tone matching which often conflicts with cutting for best yield. Actual surface area plus 20% is "typical" if all you need to consider is having enough wood. But you may end up short if you start paying attention to aesthetics.

[Rod Sheridan]

I would use 30 to 50% more board feet than finished surface area.

Planing and jointing take at least 25%, another 25% for grain/colour and defects isn't unreasonable for one off projects.

Now if you start making an entire house full of furniture from one species, you can reduce your waste because some of it can be used on other pieces of furniture.

Regards, Rod.

[Scott Hildenbrand]

Oh I don't doubt that some will be tossed around to various projects.. One substantial project is going to be paint grade, but another I'm wanting to go ahead and have stain grade.

I think 25-30 sounds fine for paint grade then and for stain will be upwards of 50% more board foot.

Seems like I'll have to pay attention to material and part lengths.. Shouldn't be too bad though..

Thanks for all the input! :D

[Steve Rozmiarek]

Scott, if you use your Cutlist software to do a bill of materials, and your supplier has exactly what you need in stock, you can nail this extremely close. Chances are though, that Cutlist will call for a particular board, say 8'x8", 4/4, and the board that you can buy closest to that will actually be 9" wide, and have a knot to work around. Point is, if you want to get it exactly right, do a Cutlist bill of materials, then go look to see what you can actually get, then redo the Cutlist to see if the tweaking of available stock can minimize the waste. Better yet, just bring your laptop to the lumber yard to tweak on the fly!

You can also work Cutlist from an inventory angle, and enter the suppliers inventory, then let the software pick from the available boards.

Or do my approach, and buy way too much to begin with, and always have some inventory on hand. Or maybe a lot of inventory...:o