Except for the seat cushions, all the materials you need are available at home centers. I chose cedar-colored treated lumber. Naturally rot-resistant woods like cedar and cypress would also be good choices, though they’ll cost you an extra $80 or so.
Treated lumber is notorious for warping as it dries, but I’ve had good luck with this approach: I buy treated lumber about three weeks before I plan to build. I carefully select goodlooking boards and buy about 25 percent extra so I can cut out large knots and other imperfections. At home, I stack the lumber on sawhorses in the shade. I don’t want the sun to bake the wood—fast, uneven drying leads to warping. Every few days, I rearrange the stack so that all boards get some surface air exposure.
Just the Basics
This project requires only the most basic tools and materials: a few hand tools, three power tools and standard dimensional lumber. The skills needed are basic too: Just cut parts and screw them together. There are a few tricky cuts, but they don’t have to be perfect. And if you make a mistake during assembly, you can remove a few screws and try again.
If you don’t find any seat cushions you like, look online. I bought bullnose rectangular 18-in.-deep cushions at homedecorators.com. I picked a 48-in. cushion (about $60) for the short sofa and a 59-in. cushion (about $75) for the long one. If you find a style you love but it isn’t quite the right size, you can adjust the sofa dimensions. Notice that parts D, K, L and H can be customized to any size you’d like.
Self-drilling screws work great for this project. The screws drill a pilot hole into the soft wood as they turn, allowing for quick assembly. Use the slim 2-in. trim-head screws for the seat and back slats and the taper-head 2-3/4-in. and 3-1/8-in. construction screws for the thicker lumber. You can hide the screw heads with filler or leave them exposed. Be sure to use exterior screws that are rated for treated woods.
This is one of the simplest furniture projects I’ve ever designed. Still, it has a few steps that might challenge beginning builders. Follow these tips to get yourself over those hurdles:
- Here’s how to avoid mistakes when making the legs (Photo 1): Mark and cut one leg, then doublecheck the measurements and use that first leg as a template to mark the other three.
- Don’t worry about getting exact bevel cuts on the seat struts (Photo 3); they’ll be covered by the seat slats. So even if they’re not perfectly straight or smooth, they’ll still allow the seat slats to lie flat.
- If you’re not using a miter saw to make angled cuts on parts E, F and G, you’ll need a protractor or similar tool to mark the angles. You’ll find various angle marking tools at home centers, starting at about $10.
- When you’re assembling the seat frame (Photo 4), install the two seat braces at the ends first. Then make sure the seat frame fits easily inside the tables. If not, you can easily cut all the seat braces just a bit shorter. The exact dimensions of treated lumber can vary slightly, so the brace measurements in the Cutting List may need to be altered.
- The back braces look complicated. But like the seat struts, they don’t have to be perfect. Cut one brace, use it to mark the other two, and then cut 3/4 in. off the middle brace.
- If it’s difficult to slide the seat frame into the tables, back out two of the screws that fasten the bottom shelf to the legs. That will allow the legs to spread slightly. Then, when the frame is in place, retighten the screws.
- When you mark the seat slats for notching, don’t determine the notch locations by measuring. Instead, set the slats in place and mark the notch positions along the back braces or table.
The cedar-tone treated wood needed a bit more color, so I used a closely matching waterborne semitransparent outdoor stain. The slight pigment evened out the appearance.
Use long, even brushstrokes and stain the boards and panels one at a time to keep the stain from pooling or blotching. I set the bench on a drop cloth and rotated it to brush the back and undersides as I went.
Let the finish dry at least two days. Finally, nail a pair of plastic furniture guides onto the bottom of each leg to help keep the legs dry.