Bountiful sunshine makes our gardens grow, but all living things need a little shade sometimes — especially people. These step-by-step plans will show you how to build a pergola to create your own backyard shade. The finished product will add stylish definition and shape to your yard and garden. If you’re looking to increase the amount of outdoor space you have, as well as the amount of time you can spend enjoying your outdoor space, then exterior folding arm awnings are exactly what you are looking for.
A pergola (also known as an arbor) can be an elegant entranceway over a path, a quiet place to sit, or a frame for vines to climb over a deck or patio. Our pergola plans create a structure that’s large enough to span a picnic table, but you can make the dimensions narrower and shorter so yours can serve as a garden entrance. The 6-by-6 and 2-by-8 lumber used in these plans looks great and is more than strong enough for the job. You can use thicker or thinner planks, or even peeled poles you’ve foraged. (For instructions on how to build a pergola using logs and poles, see How to Build a Pergola Using Peeled Poles.[link to sidebar])
Step 1: Install the Pergola Posts
Building our pergola begins with the same challenge encountered in many outdoor projects: installing a series of vertical posts at exactly the same height. The cardinal rule is to bury first and cut later. This is the best way to install your pergola posts, because it’s nearly impossible to dig a set of holes to the identical depths required for pre-cut poles.
Begin building your pergola by marking six posthole locations using spikes pushed into the ground, then dig oversized postholes that are 24 to 48 inches deep. Hoist your 6-by-6 posts — each of them 12 to 14 feet long — and tip them up and into the holes. Plumb the poles temporarily with 2-by-4 braces and, when all of the posts are in alignment, fill the holes with soil. Compact the soil around the posts using a long piece of wood. I’ve found the end of a sledgehammer handle to be ideal for this type of tamping. There’s no need to set your posts in concrete, because this pergola is self-supporting. The posts will stand solidly so long as you firm the soil all the way to the bottom of each posthole. (Want to cut your own posts and boards for this project? See Use a Portable Sawmill to Make Your Own Lumber.) 
Step 2: Make Pyramid Cuts
After all of the 6-by-6 posts are set solidly into the ground, you’ll need to mark and cut the tops to exactly the same height. You’ll probably appreciate some extra hands to help with this step. Start by measuring and marking the first post about 8 feet above the highest area of soil. Grab a 2-by-4 that’s long enough to span the space between the posts, turn it on its edge, and hold it parallel to the ground at the first pole’s 8-foot mark. Set a level on the top edge of the 2-by-4, maneuvering it into a level position, and then mark the second post where it’s crossed by the 2-by-4. Repeat until all of the posts are marked. This approach is the only way to get their tops perfectly level.
Post tops that have been cut square look surprisingly ugly. For improved aesthetics, trim each post with four angled cuts — 15 to 20 degrees from square — using a hand-held circular saw. You’ll find 6-by-6s too thick for a standard circular saw to chew all the way through, but that’s OK. Just make four angled cuts — one from each side of each post — then complete the cut with a handsaw. Your post top will then have a pyramid shape. Saw marks look ragged, so refine them with a belt sander spinning an 80-grit abrasive. Tedious? Yes. But trust me — it’s worth the results. 
Step 3: Place the Crossbeams
Now that your pergola posts are up and trimmed, it’s time to fasten the three 6-by-6 crossbeams to them. At this point, you can remove the 2-by-4 braces from the posts. Measure the distance between the outer faces of the posts, then cut the three main crossbeams you’ll need to span them. Allow 12 1/2 inches for overhang on each end (see our lap joint drawing under Step 4 for precise measurements). Cut the crossbeams to length and trim the ends with pyramid cuts (as you did with the post tops).
Use the helping hands you’ve recruited plus props to temporarily hold up the crossbeams with scrap lumber, make sure the beams are level, and mark the place where the posts and the crossbeams overlap on the outer faces of both. You could just mark the spot using a tape measure and level, but beware — bows or bends in the beams could prevent the joints from fitting together well.
Step 4: Shape the Lap Joints
Lap joints are the way you’ll connect the posts and crossbeams. A lap joint is simply a pair of interlocking notches that fit together like Lincoln Logs. Wherever your posts and beams overlap, that’s where you’ll need a lap joint for support. Prepare these joints by making multiple cuts with a circular saw every quarter-inch or so, then knocking out the remaining chunks of wood using a mallet and chisel (see the illustration in Step 2). You’ll need to do this work with the posts installed in the ground, of course, and that won’t be easy. Preparing the joints on the crossbeams will be much simpler, because you can support them on sawhorses while you’re sawing and chiseling.
Note that a standard, 7 1/4-inch circular saw makes cuts only about 2 1/4 to 2 1/2 inches deep — too shallow to produce a lap joint groove halfway through a 6-by-6. A better and easier approach is to make offset lap joints that aren’t flush but have about a seven-eighths-inch offset. The effect looks pretty good when you position the overhanging faces of the crossbeams on the outside faces of the posts. (Study the lap joint diagram here.)
How to Build a Pergola for Backyard Shade – Do It Yourself – MOTHER EARTH NEWS.