Utility Trailer Floor Replacement


We all have those projects that we want to do or need to do, but never make the time to do them for whatever reason. For me, replacing the wood floor in my utility trailer was on that never ending list. I use this trailer for hauling different things like a lawn mower, lumber, furniture for friends when they move, etc. I was always careful not to park the mower on a rotten board and made sure the tires were positioned over the angle iron supports. I had to take extra precaution with some of the boards being partially rotten. I even fell through one of the boards once, not too long ago, while walking on the trailer. I still have a messed up pinky finger because of it. So, it’s time to make the necessary improvements before something worse happens. Watch the full project build video above. Subscribe to our YouTube channel so you don’t miss any future videos from us.

New trailer deck completed

Out with the old

Before doing anything, the first thing I had to do was to take off a piece of angle iron at the back of the trailer that is used to hold the boards down. The way this works is there a bolt that runs through the top angle iron piece, through the board, and also through the angle iron on the underside of the trailer.

Angle iron end cap

I removed the top angle iron by cutting a bolt that was rusted into the trailer. I needed to get rid of the old and rotten wood and also the bolts that were used to hold the boards down in the center of the trailer.

Cutting rusted bolt

Some of the boards broke away very easily and some were so rotten they just crumbled. I did have a couple of boards that were in decent shape and I probably could’ve left them, but I wanted to replace the entire floor at once.

Old wood trailer deck

I started by ripping out what I could and spraying WD40 on all the bolts that were rusted to the trailer frame.

Rusted bolts with wd40

The floor support construction of this trailer is angle iron and the center cross support is where the boards are attached with a bolt through the board and also through the angle iron. Over time the bolts have become rusted and were very difficult to remove. So, I sprayed all the bolts with WD40 in hopes of the rust giving away to remove them. Some bolts came out, but there were a few that broke off.

Rusted bolt

Once all the old wood was removed and all the bolts were out of the way, I cleaned the frame to get it ready to install the new floor.

Clean trailer frame

Preparing the new wood

The overall size of my trailer is five feet wide by fourteen feet long, so I had to buy sixteen feet boards. I went with treated two inch by eight inch boards and like I mentioned sixteen feet long. Selecting the right boards is important because you want to make sure the boards are free of any defects as with any project.

One thing to note as you’re selecting the individual boards is to try not to get boards with double knots. Boards that have knots side by side are going to be weaker than a board with just one knot. If you were to remove the double knots on a board, especially on a eight inch wide board, you’ll notice that the amount you’re left with is probably less than a couple of inches. That doesn’t leave much support in that particular area on that board.

Knots aren’t necessarily bad just the ones with double knots can be problematic over time. I knew I would be cutting a couple of feet off the end of each board, so I could be a little less selective on one end or the other.

board with a double knot

Treated sixteen foot boards can be heavy, especially after lifting eight of them, so I moved the boards back onto the trailer after cleaning it off to get them ready for installation. I lined all the boards up and cut off each end at the desired length. My system was to prop the board up with a scrap piece of two by four, measure, strike a line, and cut it with a circular saw. Now that the boards were all cut to the correct length I could start on the installation of the new floor.

Cutting wood to size

In with the new

As I mentioned, this trailer is made up of angle iron cross supports for the floor, but really the entire trailer is nothing more than a bunch of angle iron welded together. So, since I had all the boards cut to length I just had to put them in place and secure them. Starting with one of the outside boards I slid it into place and secured it from the underside through existing holes in the angle iron with a screw in the center.

Remember, the back of the trailer will have a piece of angle iron that will basically cap off all the boards at that end so they can’t move and a screw from the under side in the center of the trailer will keep the middle of the board from bouncing around. The front of the trailer is made a little different than the back, instead of the board resting on a piece of angle iron and capped with another piece of angle iron there’s a U channel that each board slips into.

If you’re not familiar with what a U channel is, hold up your pointer finger and thumb on each hand and make your thumbs touch, that is what a U channel looks like.

Front channel for deck boards

When installing the boards, the front of the board slips into that U channel and the rest of the board is laid in place and is secured with screws or bolts and capped at the back with angle iron. The front and back of the boards are secured and can’t move or bounce around and the center of the board is also secured, so this makes for a solid floor in the trailer.

New trailer deck completed 2

As each board is installed I use my speed square to space them evenly across the trailer. Allowing the wood to move is important, as with any outdoor project the weather will cause movement in the boards. The center of each board is secured to prevent the board from sliding around, but the ends of each board are free to move side to side.

spacing the deck boards

When it came time to install the last board the space left over was less than the full width of the board, so I had to rip the entire board at six inches. To accomplish this I took my speed square and referenced the edge of the board as I moved down the board with a pencil at the six inch mark.

Marking the last board for a rip cut

This gave me a nice straight line the full length of the board to follow as I ripped it with a circular saw. The last board fit the final space with the same spacing as the rest of the trailer floor.

Installing the last board

The last step to complete this project is to reinstall the angle iron at the back of the trailer to cap off the ends of the boards. This is done by securing it with a few screws from the top side. Adding screws and washers on the underside made sure the boards were fastened to the angle iron below.

Back angle iron cap

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Tools used in this post

Power Tools:

• Circular saw: http://amzn.to/2nj39MQ

• Reciprocating saw, Porter Cable: http://amzn.to/2snzxU3

Drilling and Accessories:

• Drill and impact 20v, Porter Cable: http://amzn.to/2txekak

• Drill and drive bit set, Kobalt: http://amzn.to/2stIbf6

• Drill bit set 21 piece, Kobalt: http://amzn.to/2urlY2G

Jig Accessories and Fixtures:

• Saw horses (similar): http://amzn.to/2q6Qjo9

Measuring, Marking and Layout:

• Nylon 16′ tape measure, Milwaukee: http://amzn.to/2txJfDN

• 8″ plastic speed square, Swanson: http://amzn.to/2urfvVn

• 7″ metal speed square, Swanson: http://amzn.to/2ts6JJI


• Safety glasses, 3M: http://amzn.to/2txHtT7

• Hearing protection with Bluetooth, ISOTunes Pro: http://amzn.to/2x1otdR

• Work framer gloves, (similar): http://amzn.to/2yXBxoh

• Fire extinguisher: http://amzn.to/2ururTy

• First aid kit: http://amzn.to/2urwR4B

Video Equipment and Electronics:

• DSLR camera and mic, Canon/Rode: http://amzn.to/2urN0qA

• Camera battery pack, Canon: http://amzn.to/2sudLcx

• Mic wind muff: http://amzn.to/2urLqoy

• Tripod, Manfrotto: http://amzn.to/2s9MHjB

• Mic for voiceover, Snowball: http://amzn.to/2spgI2K

• Backpack for laptop (modified for camera): http://amzn.to/2sppNsC

• Memory card, 64gb: http://amzn.to/2s9hPzC

• Memory card waterproof case: http://amzn.to/2suLliC

• Laptop, MacBook: http://amzn.to/2urnDFx

• Network Attached Storage, 6TB: http://amzn.to/2suvRLu

Other tools I use


*Most of the links listed above are Amazon Affiliate links

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  1. Liked the video, the first thing I did was yell use “viceGrips on the nut, with penetrating oil” but you explained after I yelled!!
    I do not use a trailer, after bending my boat trailer I gave up on Backing-up, put ball on the front bumper and never had a problem put the trailer where I wanted it. Still hate driving with a trailer!!


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