Choosing lumber can be tricky! Even after you've decided on a type of wood and calculated the dimensions you'll need, every board is different and it takes time and patience to get lumber that will really make your finished project sing.

The Three Biggest Tips

Unless you're just looking for material inspiration, always go lumber shopping with a plan! Lists and sketches are both great.
Always get to the lumber yard or hardware store with plenty of time- spending an extra 30 minutes now can save you hours of project time later!
Prepare to be flexible! Based on the availably in the lumber yard, you might want to choose a different kind of hardwood or adjust some dimensions. Be open to creative opportunities and don't be disappointed if you can't find exactly what you had in mind.

You will need-

A plan, list, or sketch
Tape Measure
Means of Transportation

Optional-

Gloves
Washi Tape

Step 1: Write Down What You Need

Everyone has experienced the overwhelming feeling of going to the grocery store on an empty stomach- going to the lumber store without a plan can be similarly paralzying!

Write down a detailed list of the boards you need or draft a quick annotated sketch. Think about organizing boards into "like groups". For example, if you're building a very simple bookshelf you'll need a set of boards for the shelves, top and bottom and a set of two boards for the sides. Creating groups will help you make better decisions in the lumber yard. You'll know which dimensions are flexible and which are fixed. For example, certain dimensions can be flexible as long as they are consistent- it wouldn't matter for your bookshelf if all the boards you buy are 8.5 inches or 9 inches wide but they do all need to be the same width.

Note: This is a great time to think about how you're going to transport your lumber. If you drive a Honda Civic you might be able to squeeze in 8ft trim boards but only fit 6ft full sized boards. Mentally think through the path you'll have to carry your lumber. If you need to take it into an apartment elevator you might have to get several shorter boards instead of a single 12ft board.

Step 2: Decide on a Type of Wood

The first step is to decide what type of wood you'll be using for your project. If you're building interior furniture and want to have exposed wood, oak and maple are good choices. Oak and maple are strong and stay relative straight while you're working with them. If you're building interior furniture that will be painted, medium density fiberboard (MDF) is solid and uniform. MDF is often available in wider boards than hardwood boards. If you're building garage shelves or framing projects that will be covered in another material (drywall, paint, ect.) then save money by going with pine or fir. Pine and fir boards will be rougher and are great for projects where perfection isn't the highest priority. If your project is outdoors (garden fencing, decking), consider using redwood or cedar which will hold up against the elements.

Step 3: Check Your Dimensions

Never assume the stated dimensions are accurate!

Boards are sold by either their cross sectional dimensions and their length (for example, 1"x2" red oak trim boards are $2 per ft) or by volume, measured in board-feet or BF (for example, red oak boards are $24 per BF). One BF is the volume of a board 1 ft long, 1 ft wide, and 1 inch thick.

Certain kinds of lumber are sold by their pre-milling dimensions- for example the most commonly used board- a "2x4" or "two by four"- is usually actually 1.75 inches by 3.5 inches. The two inches by four inches refers to the dimensions before the board was finished to a relatively smooth rectangle.

Some lumber yards will report board thickness in inches (2 inch) while others use quarter inch increments (a 2 inch thick board would be labeled 8/4).

Almost all boards will be smaller than the stated dimensions so it's important to measure all critical dimensions yourself to prevent any unpleasant surprises later in your project.

Step 4: Check for Spot Defects

Inspect your boards for spot defects (knots and cracks).

The most common lumber defect is a knot- this is where a branch was connected to the main trunk causes the wood grain to spiral in a circular pattern. The center of the circular pattern is a different type of wood from the rest of the board and will frequently rot, shrink, or fall out- leaving an unsightly hole and weak point in the board.

The other defect to look for are cracks. Cracks can go all the way through the board (pay careful attention to the ends of the boards) or only partially through the board (splits will usually run parallel to the wood grain along a particular growth line).

Step 5: Sight Your Edges

No board is a perfect rectangle but your projects will go much more smoothly when you use boards that are close to rectangular. If you imagine a board as a rectangle with three dimensions (width, thickness, and length) you can picture how a board could warp along any of those three dimensions.

The best way to check for a curved board is by "sighting" several edges. Rest one end of the board on the floor and hold the other end at about face level. Close one eye and look along the nearest edge- it should look straight (don't worry about perfection, if you think it looks straight you're good to go). Rotate the board 90 degrees and sight along another edge. Check both ends for cupping.

Note: Cupping can actually be desired in certain decking configurations to prevent the edges of the boards from causing trip points as they age.

Pull boards out from the racks, sight the edges, and create easily accessible piles of acceptable and reject boards. Be conscious of other shoppers and employees! Double check that you're not blocking an aisle or going to clock some poor unsuspecting soul if you spin around with a 10ft 2x4.

Step 6:

Note: Cupping can actually be desired in certain decking configurations to prevent the edges of the boards from causing trip points as they age.

Pull boards out from the racks, sight the edges, and create easily accessible piles of acceptable and reject boards. Be conscious of other shoppers and employees! Double check that you're not blocking an aisle or going to clock some poor unsuspecting soul if you spin around with a 10ft 2x4.

Step 7: Check Coloration and Mentally Plan What Goes Next to What

Remember your handy-dandy plan? This stage of buying lumber is where it really shines!

You should now be facing a pile of straight, defect-free, dimensionally correct lumber. NOW you're ready to start putting boards in your shopping flat. Using your groups, choose boards that visually complement each other. For example, you might need 8 9"x1" by 6ft boards but looking at your plan you'll know you need to choose 6 boards that are close to each other in tone and grain pattern and 2 boards where coloration doesn't matter.

Note: If you're buying more than 10 boards, label any critical groups with a quick stripe of washi tape. I can't count the number of times I've pulled a perfectly matched set of trim boards in the lumber yard only to accidentally cut one of them up into hidden spacers in the heat of the moment.

If you're buying a lot of boards, buy extras. Especially if you're framing out a large project with 40 2x4s, insure yourself with 3-5 extra boards. You'll be seamlessly prepared if you missed a major defect or warped board or if you need an extra piece you forgot to count in your original plan. Even when planning hardwood furniture, get an extra trim board. Even if it doesn't make it into the final project you'll love having a unquestionable sample to test the look of stains and finish options.

Before you head to checkout - sort and re-stack your rejected boards back into their appropriate bins!

Step 8: Go Forth and Build!

Armed with wood selection knowledge you can make informed choices when at the lumber yard.

Giving yourself extra time to shop for the best wood definitely pays off, but also allow yourself to be a little flexible as you're not always going to find perfect cuts every time. Just like grocery shopping on an empty stomach is a bad idea, shopping for lumber without a plan is sure to end in missed items or too much of something you don't need.

I hope this helps you on your next woodworking project. Happy woodworking!