There's no shortage of free treated lumber on Craigslist.

So if you end up rebuilding or tearing down part of a deck, you might find yourself in a predicament. What to do with all of that weathered-and-wavy-yet-still-decent deck wood?

Before you send your lumber pile to the dump, here's one project to consider. It's a DIY lawn mower dump cart made almost completely from deck wood.

Lawn tractor dump carts can cost about $140 new. Used carts can range from $40 to $100 on Craigslist, depending on your luck.

Meanwhile, this cart uses a mix of 4x4 and 2x6 deck-wood boards to make the frame, axles, and box. It rides on a split-axle design, which helps when crossing over uneven terrain. The hitch uses scrap angle iron from a bed frame. The 250-pound-capacity wheels were $6 specials from Northern Tool, though $4 equivalents can be had on sale from Harbor Freight right now. Add a mix of nuts, bolts, washers, hinges, and leftover deck screws, and the total comes in at less than $25.

Watch the attached video for a detailed breakdown.

Step 1: Parts

A lot of these parts were based on supplies that I had available. In a way, the dimensions are equally arbitrary: They are a balancing act between the width of my lawnmower, the size of commercial dump carts, and round numbers for easy figuring. You'll have to decide your dimensions to a certain degree, but I'll be as specific as possible when necessary and lay out your options when they're available.

A pile of treated lumber from a former deck. Treated because this thing will likely spend time outside in bad weather. Deck wood because it's readily available for free on Craigslist (at least in my area). This pile should consist of a small amount of 4x4 pieces, a large amount of 2x6 pieces, and a decent amount of 2x2 pieces, though the 2x2s can be ripped from a 2x6. If you can't score any of this for free, you'll likely be able to pick it up for cheap from a hardware store. If you're in that situation, I recommend making the walls of the box out of plywood instead of planks because it will be easier and lighter, yet still strong.
A pile of deck screws. I reused the 2½" screws that I took out of my old deck. As long as the heads are in good shape and they aren't too rusty, reusing them should be fine. If you are going to buy some, buy the Robertson aka square-drive screw head type. These heads are much less likely to strip.
2 x wheels. I chose cheapo $6 specials from Northern Tool. Harbor Freight and pretty much everyone else has the same kind, which regularly go on sale if you wait long enough. They each have a 250 pound capacity, giving the cart 500 pounds of hauling capability—in the wheels, at least. One way to save money here is by finding free wheels from Craigslist. For example, you could use bicycle wheels, as shown in a plan for a large human-powered wheel barrow from The Family Handyman. Instructables member tjdux's cart also uses bicycle wheels for a grass clippings trailer. Using bicycle wheels would take some significant modification to this plan, but hey, free is worth a little extra brain power.
Axle hardware: 2 bolts, 6 flat washers, 2 lock washers, 2 nuts, 2 cotter pins. The size will depend on your wheels. My wheels needed a 5/8" diameter axle, so I needed 5/8" bolts. For the bolt length, tally up the depths of the wheel, axle support board, and axle nut, then round up to to a length that will give you at least 1/2" beyond the wheel. I used 5½" long bolts. For the cotter pins, you can buy actual cotter pins, or you can bend up a steel nail. I used copper wire in the video, but I wouldn't recommend that. It's too soft for this purpose.
Frame hardware: 2 bolts, 4 flat washers, 2 lock washers, 2 nuts. These will hold together the two 4x4 beams that make up your frame. I used 4½" long 1/2" bolts, but I probably should have used 5/16" bolts instead. That would have left more wood in that critical crosspiece.
Hitch receiver metal: I used a piece of bed-frame angle iron cut down the middle lengthwise to make up the top and bottom of the hitch. You could do the same or buy some 1" x 1/8" flat stock steel from a hardware store. I used a 7" piece and cut it in half down the length to end up with two 7" long, 1" wide pieces.
Hitch hardware: 2 bolts, 4 flat washers, 2 lock washers, 2 nuts. These will clamp your hitch receiver metal to your hitch tongue. I should have used 2½" long 1/2" bolts, but I used longer ones and cut them down. Shorter bolts here would have saved money.
Hitch pin and cotter pin: I lucked out and found a 1/2" hitch pin in a bin of loose bolts in my garage. If you aren't so lucky, you could easily use a 2½"-long 1/2" bolt with a hole drilled for a cotter pin. My cotter pin was another piece of steel wire here.
2 x hinges: I used basic, hardy gate hinges and secured them with deck screws. Mine was 3" wide on the base and 4" long on the triangle.
Latch hardware: 1 long bolt, 1 cotter pin. This will secure the dump box in the down position when you're not actually dumping anything. I would recommend getting an actual cotter pin for this purpose, considering you'll be taking it on and off any time you want to dump the box.

Step 2: The Frame

Basically, you are going to turn two 4x4 boards into a T by cutting notch joints into each board to join them together. Then you'll drill two holes through that cross piece and use two bolts, lock washers and nuts to hold the two together.

For reference, my hitch "tongue" was 41" long. The cross member was 27".

For the notch joint, first, set your circular saw or table saw blade depth to half the depth of the board. Starting with the tongue, make your first mark 2" from the back end of the board. Use the other 4x4 as a pattern to determine the width of the notch for your second mark. Then carefully slice the beginning and the end of the notch, stopping the saw completely to precisely line up the blade. With those precise parts finished, you can saw away at the wood between those two marks. Either saw a bunch of slots that you can chisel out later or completely saw the wood away. Both ways work, though Option B takes more time and is more dusty.

For the cross member, you'll mark the center of the board, then line up the center of the other 4x4 again to use as a pattern for your marks.

You could even use a sliding miter saw for this. Here's one example.

Step 3: The Axles

Each side gets three boards: an end cap and two braces. My end cap was 10" long and 3 1/4" wide, but the width just needs to match up with the width of your 4x4. (What? A 4x4 isn't really 4x4? Shenanigans!) You can reference the end board to help cut the two braces out of one 2x6. Mark the depth of the end cap on the top right corner, then the bottom left, then use a ruler and draw a line between the two points. Now, when you cut along that line, you'll have two nice beveled support pieces.

Next, you can use your wheel to mark the axle hole on the end cap. I marked mine about 2" from the bottom of the end cap. This kept a good amount of ground clearance between the bottom of the end cap and the bottom of the wheel, and it kept the top of the wheel under the bottom of the dump box. (The top clearance wasn't necessary, but I did it just in case.) Drill the axle hole out. Then screw on the axle hardware. Here's the order of parts starting from the inside and installed: bolt, flat washer, end cap, flat washer, lock washer, nut. Now you can slide on the wheel and wheel flat washer. Mark the next thread away from the washer on the bolt, then remove the wheel and washer again.

Next, drill a hole through your bolt for a cotter pin. Use lots of oil, and take your time.

Reinstall the wheel washer and wheel with your cotter pin. Now you can screw the braces onto the end cap (you might have to pre drill these) and then screw the end cap/braces onto the frame. It's best to pound the axle assemblies onto the frame with a mallet, then set that on the ground to level it out before screwing everything together for good.

Now is also a good time to check the tire pressure and fill the tires if needed.

Step 4: The Bed

For reference, my box came out to be 25" wide x 12" tall (from bottom of base to top of wall) x 42" long. That was based on a combination of commercial carts, the width of my tractor, and the width of my boards. I used a 5-plank-wide design, so naturally, I cut my braces to be 5 planks long.

This is pretty simple. Square up your first bed board on the bed braces, putting the braces a couple of inches from each end, and putting the board flush with the end of the brace. Screw it on. Then place two spacers alongside that board and attach the next, repeating until you are finished. I used old washers as my spacers, but those got stuck. I would recommend using something long enough for you to pull out.

Next you'll set the bed aside and attach the hinges on the frame. I put my hinges halfway between edge of the frame tongue and the end of the end caps. Use a yardstick to keep the hinges parallel and some clamps to hold them tight while you screw. Then you can attach the 4x4 hinge beam. I clamped on some shelf brackets to hold up the beam while I screwed it on.

Next, you'll put a 4x4 latch beam down at the hitch end of the trailer tongue. I made mine about 1½' long so that there was both plenty of beam to support the bed and to create a latch to hold the box in the down position.

Square up the bed on the frame. The front of the box should be a little heavier than the back, to keep it from accidentally tipping back, so I mounted the bed with the center just a smidge forward of the hinge beam. Screw the bed to the hinge beam and the latch beam.

Cut up two 2x2s for the latch supports. Notch them if your latch bolt isn't long enough to go through both with the frame tongue between. Drill holes for the bolt and two screws you'll use to attach each piece. (These small boards will absolutely split otherwise.) Finally, drill a hole through the latch beam, feed your latch bolt through the three pieces, and screw the latch supports in place.

Step 5: The Hitch

Mark the end of the frame tongue into thirds. (Jimmy DiResta has a great trick for this.) Then use a circular saw or hand saw to cut slots on those third marks. (If you use the circular saw, be careful! My saw fought me a bit on the end grain.)

Slice up your hitch steel. I used angle iron from an old bed frame. You'll want to end up with two flat pieces, so you'll have to rip it in half along the length. For reference, I created two pieces that were 7" long and 1" wide. Then jam those pieces into the slots, drill some holes for the bolts and hitch pin, and bolt everything together. By drilling everything in place, you can be more sure that all of the holes will align.

Finally, hook it up to your tractor. Most tractors will have 1/2" hitch receivers, so a 1/2" bolt with a hole drilled at the end for a cotter pin will work in a pinch.

Step 6: The Box

We'll be finishing up by building the box mostly in place.

Start by cutting two 2x2 notches along the edge of the bed at the middle of the braces on each side for the box wall posts. (You could do this before you attach the bed, but it's doable either way.) Again, be careful here if you're using a circular saw. Don't be like me and cut into a screw! Then start screwing your box post brackets on the outside of those notches. Like before, these 2x2 pieces need to be pre drilled, or else they'll split.

Clamp some supports under the notch holes on the left side. Drop in your wall posts, which will rest on the support while you build. Then drill and screw away, attaching the box boards on the inside of the box supports. You'll need shims again here between the box boards. Use a speed square to keep everything square. Once built, you can pull the wall off and trim the box supports flush. Repeat on the right side.

Measure the final height of your walls, then cut 8 matching lengths of 2x2. Two will be used on the front, flush with the front edge of the box. Drill and screw two box wall boards on the inside of those 2x2s to make the front wall. Four will be attached in the back for a gate channel, with two screwed flush with the end of the box and the other two set far enough forward to make a gap that is a hair wider than the width of your wall boards. Finally, drop in your two back gate boards and drill and screw the remaining 2x2s in at the 1/3 points along the length, creating an easily removable gate. (Heads up: The width might be different between the front and the back. Be sure to measure both.)

Once you drop in that back gate, you're done!

Step 7: The Test

Head out! But be cautious at first. Watch for splits. Check on the wheels to make sure your cotter pins are holding up. Make sure no screws are ripping out. Mine has held together great.

If you want, give the cart a fresh coat of stain or paint. I'm leaving mine the way it is until I stain my deck this summer.

More importantly, send me some photos. I'd love to see how your cart turned out! Hit me up on Twitter, Instagram or email.

Thanks for reading, and good luck!