Time, tools and materials
Building this timber bench is surprisingly fast. If you have some experience with power tools, you’ll have it built in just a few hours, though staining it may add a couple hours more. You can build it with just a drill/driver, circular saw and basic hand tools, but you’ll get faster, better results if you also have a router and a random orbit sander.
All the materials are available at home centers. When you’re choosing timbers, take the time to pick through the pile for the straightest ones. They’ll twist a little after you build the bench (see “One Year Later” at the end of this project), but they need to be nice and straight when you’re cutting the joints and assembling the bench.
3 basic parts
This bench is made entirely from pressure-treated landscape timbers and a few galvanized lag screws and washers. Add black spray paint and exterior stain and you’ll have a beautiful, low-maintenance bench. The hardest part of the project is picking through the pile of heavy landscape timbers at the home center to find the best ones.
1. Mark the lengths of the parts
Three of the landscape timbers will become the “beams” for the bench’s seat. The timbers are slightly longer than 8 ft. when you buy them, so you’ll need to cut a little off each end to make them exactly 96 in. long. Set each timber on a pair of sawhorses and use a Speed Square to draw a pencil line on all four sides (Photo above).
2. Cut three times
Set your circular saw blade for a full-depth cut. Then, using your square as a guide, make the first cut on one of the wide “faces” of the timber. You won’t be able to cut all the way through in one pass; doing three passes works well (Photo above).
When you finish the first cut, flip the timber on edge, start the saw and slip your saw’s blade partway into the “kerf” (slit) you just made to align the blade for your second cut. Guide the saw with your square again, finish the second cut, then flip the timber one more time and do the same thing to make the third and final cut. Now cut the rest of the parts to length the same way.
3. Sand off saw marks
Remove any saw marks left behind with a random orbit sander and 60-grit sandpaper.
4. Mark the notches
The joinery that connects the legs to the seat beams looks complicated, but it’s really simple. The outside beams of the bench’s seat are supported by L-shape notches in the legs. U-shape notches are also cut into the seat beams so the leg’s faces can sit about 1/4 in. proud of the beams. The notches are all formed the same way using a circular saw, a square and a sharp wood chisel.
Tip each of the outside beams on end and, using a pencil and your square, mark layout lines for the sides and bottoms of the notches (Photo above). Make X’s to remind yourself where to cut.
5. Make the shoulder cuts
Set your circular saw blade to the proper depth and then, using the square as a guide (clamp it down if needed), make a perfectly straight cut on each side of the notch (Photo above). This will define the outsides of the notches in the legs and beams (Figure A, in project PDFs below). The beams get two shoulder cuts per notch. The legs get one shoulder cut per notch.
6. Make the kerf cuts
Cut a series of freehand kerfs between the shoulder cuts you made for the notches in the beams. The legs have only one shoulder cut per notch, so start your kerf cuts at the ends and work toward the shoulder cut.
7. Knock away the slivers
When you’re done cutting, knock out the thin slivers of wood with the claw of your hammer.
8. Chisel the notches smooth
Smooth the “cheek” of each notch (Figure A, in project PFDs below) with a sharp wood chisel.
9. Round over the edges
The edges of the seat beams and legs are sharp and can give you splinters, so deal with them now before you assemble the bench. Lay the beams and legs on sawhorses and knock off all the sharp edges with a router and 1/4-in. round-over bit (Photo above). Be sure to go counterclockwise with the router. If you don’t have a router, you can do the job with a block plane, a sanding block or a random orbit sander. Don’t round over the edges of the notches.
10. Drill pilot holes for lag screws
If you’re planning to stain your bench, do it now before you assemble all the parts. You might need to let the wood dry out a bit before staining because pressure-treated lumber is very wet when you buy it. Be sure to read the directions on the can.
Set the outside beams for the seat upside down across your sawhorses with the U-shape notches facing out and fit the L-shape notches of the legs into each of the U-shape notches. The L-shape notches should fit snugly into the U-shape notches and the tops of the legs should be flush with the tops of the seat beams. The faces of the legs will sit a little proud of the seat beams—about 1/4 in. If the joints won’t go together by hand, knock them together with a rubber mallet or dead blow hammer. If they still won’t go together, you might have to fine-tune the fit of each joint with your chisel.
Set the third beam (the one without notches) between the other two beams, making sure the spaces are even—about 1/2 in. Now set the ledgers between the legs, pull everything together tightly and use long clamps to hold it temporarily. Drill pilot holes through the tops of the legs for lag screws (photo above)—two through each L-shape notch and one below each notch’s shoulder (Figure A) and drill one hole in the center of each ledger.
11. Paint the lag screws and washers
Next, spray-paint the heads of the lag screws and washers and let them dry before driving (Photo 11). Save the car for future touch-ups.
12. Drive the lag screws
Once they’re dry, drive the lag screws with washers through all the pilot holes you drilled (Photo above). An impact driver with a socket works great for this, but you can also use a wrench or ratchet. Touch up the tops of the lag screws with more paint if they get scuffed up (spray a little on a disposable brush).
One year later…
This timber bench sat outside, completely unsheltered, through a hot summer and a hard Minnesota winter and it still looks great! The timbers twisted a little, but that just added to the rustic look. The joints on this timber bench loosened up a bit from wood shrinkage, but that was easily fixed by tightening the lag screws.