How Much Extra Lumber Should You Buy for Waste?

Buying exactly the amount of lumber shown on your cut list may look like an efficient way of handling things, but reality is that woodworking and construction jobs rarely make full use of all the materials that they get. To begin with, you will have to trim, square, and cut the materials. Besides that, there is a possibility that certain joints will be discarded due to knots in the wood, warping, or even damage that the lumber had already incurred before you got your hands on it.

This is why including a lumber waste allowance should be part of your overall plan when ordering your materials.

A general rule of thumb, for example, would be adding 10-15 % extra lumber to the cut list for many of the basic projects. However, it would be wise for you to increase the allowance in case you are working with unusual shapes, very defective, lower-grade pieces of wood.

Why Do You Need Extra Lumber?

Well, lumber waste doesn’t necessarily mean that you have taken a wrong step. Some waste is just a fact of the building process.

Generally contributing factors to wood waste may be:

• Cutting boards to match measurements
• Eliminating rotten or warped regions
• Making rough-edged boards smooth and square
• Smoothening and shaping the lumber
• Trimming lumber along walls and windows
• Selecting wood with the same grain or color
• Allowing room for imperfect cuts\
• Rejecting pieces that have knots or damage

So, it is better to consider such losses in your estimate of lumber needs and not just rely on the assumption that every board purchased will be the one finally used for the project.

How Much Extra Lumber Should You Buy?

So, are you worried about how much extra lumber you should buy for your woodworking project?

Deciding the right proportion largely depends on the kind of project.

5% to 10% Extra

A 5% to 10% waste allowance will be enough to cover simple projects if it involves cutting, using standard dimensions, and the lumber is of high quality.

Examples include basic framing, shelves, or projects where board lengths match almost perfectly to the cutting length.

10% to 15% Extra

Well, a general rule for most woodcraft and homebuilding jobs is to purchase 10% to 15% more lumber than needed for the project. This gives a little extra lumber allowance for errors in measurement and cutting waste without ordering too much

15% to 30+ % Extra

The allowance of lumber needs to be much larger when the project requires difficult cuts, exotic shapes, diagonal layouts, handcut logs, or fine hardwoods that call for the selection of right grains. Also, the cheaper the lumber is, the higher the probability of defects and the need for extra material, since in such a case it may be necessary to remove the bad part.

How to Calculate Lumber Including Waste?

Before anything else, get the required amounts of lumber for your project, considering no waste. After that, you can determine the waste percentage and add it.

Imagine your project needs 100 board feet of lumber with 15% added for waste.

• 100 × 0.15 = 15 Board Feet

So, adding this percentage to the original requirement will give you the final calculation:

• 100 + 15 = 115 Board Feet

Therefore, the total amount that you need to buy would be 115 board feet.

However, using a board foot calculator will make the procedure easier, especially for projects containing boards of various dimensions, including width, thickness, and length. Moreover, for projects that are mostly estimated based on the length of the wood used, a linear foot calculator will assist in calculating the total linear footage.

Don’t Forget Board Lengths:

The quantity of wood is not the only factor affecting the amount of waste. The lengths of the boards and the cuts can play an important role.

For example, in case you need 6 feet of wood but purchase 8-foot wood boards, then the extra material may or may not be usable in another section of your project. So, a cutting plan will enable you to utilize all leftover wood for the next project.

It is especially true for decks, floors, trim, and other projects which include repetitive components.

Rough Lumber Needs More Planning:

Well, dealing with rough lumber requires extra processes in order to bring it to its final dimensions. These processes include jointing, planing, ripping, and trimming. As a result, you are likely to have some portion of the material as waste.

Therefore, you must know that the dimension that you obtain in the end does not determine the quantity of rough material that you require. So, allow some extra for the lumbering process and for possible defects, especially when you buy boards that have knots, cracks, or wavy edges.

With a Log Board Foot Calculator and its formula to estimate how many feet of board can be acquired from a log, you can easily calculate the potential yield of lumber from logs before they even get to the mill. In the end, the actual amount of lumber as well as its quality is dependent on the nature of the log and the lumbering process.

How to Reduce Lumber Waste?

Sometimes, it is not always necessary to solve problems of waste by simply buying more material; good planning may help to minimize the waste.

Try these approaches:

• A cut list is necessary before going shopping.
• Match available lengths of board against the required cuts.
• Shorter off-cuts can be used for smaller parts.
• Lumber should be checked before purchase.
• Consider the direction of grain before cutting.
• Eliminate unnecessary oversized cuts.
• Utilize usable scraps for future use.

Closing Thoughts: Extra Lumber for Waste

A single amount of waste does not suit every woodworking project. A margin of 10% to 15% can be considered adequate for most basic projects, but some projects need additional waste allowance, such as intricate cutting, poor quality lumber, and defective lumber. It would be prudent to have an allowance for waste together with a cut list.

Frequently Asked Questions (FAQS)

How much extra lumber do I need for a woodworking project?

The calculation for how much extra lumber you need for a woodworking project depends on having about 10% to 15% extra lumber for a simple project. However, add more for complex projects that require more cuts.

How much extra wood do I need for a DIY woodworking project?

Well, the lumber needed for a DIY woodworking project calculation depends on how complex the project will be and how good the wood is. 10% to 15% can be a good starting point.

Do I need to include waste in my board foot calculations?

Yes. The calculation of how many board feet of lumber with waste depends on determining how many board feet you need before adding your percentage of waste.