I have two trailers, a small one about 8 feet long and a larger 18 ft long that have rotting wood. I thought I would begin with the small one to learn how to do this. Both of them have the wood locked into metal C channel at each end. I have my own idea how I might do this. But I am looking for a voice of experience. I do own a welder, grinders, and plenty tools.

Can anyone give advice on this job?

Got to use Pressure-treated wood.

Look at the growth rings on the end of the lumber you are installing.... they'll form a "C" shape.
You want the C pointed face down. As the lumber ages, it has a tendency to cup or curl in on itself.
If you put the C facing up, it will hold water & rot out much faster.

Same thing goes when installing lumber on decks. Drives me crazy when I see it done wrong.

Wait until lumber prices come down unless they are completely unusable.

I've heard of people coating the deck with a mix of used motor oil and diesel to protect from rot. Poor mans creosote.

Here's a pic that shows what I was trying to say:

No cutting or grinding should be required. Pry up in the center of each board and you should be able to get enough flex to remove. Install the same way. Lock one end in its channel, then put a 2x4 or pry bar in the middle so you can bend the board down. Have a buddy knock the 2x4 out or let the pry bar down while you hold the bent end down far enough to fit in the channel.

Edit:
A 2x4 probably won't be tall enough (been awhile since I've done this. Here is a still shot video of what I'm trying to describe: [url] [/url]

Where is best place to purchase 18'+ treated boards? Any of the big box stores carry?

We have a 32 ft cattle trailer and we have boards milled from telephone poles. I expect my children to replace after I die.

There's a sawmill in Sanger that custom cuts Creosote (telephone poles). I have them on my trailer. Not sure if your location. But I'm sure there's mills around the state that can custom cut lengths.

Thanks for all the quick and handy replies.

I think I can bend the 18 ft boards but on the short 8 footers I thought I might have to use a cutting wheel to cut out a slot in the rear end at the middle board.

Medina county... I work in San Antonio

Home Depot shows 18 ft treated lumber on their website

Lumberman refer to that as " bark side out". Very important in anything to be painted too. Bark side out holds the paint much better . Also treated decks.... bark side up eliminates almost all grain shell out and splintering.

Allen76 said:

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Thanks for all the quick and handy replies.

I think I can bend the 18 ft boards but on the short 8 footers I thought I might have to use a cutting wheel to cut out a slot in the rear end at the middle board.

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Anchor the first end in the C channel. Anchor the other end with a board or heavy strap. Use a floor jack or bottle jack to bend them. I'm thinking on the loose-end anchor you'll have trouble getting a firm anchor in the middle... Work on one side only, and once they're in the channel slide them to the other side, then you work with just one jack setup.

If you're positive it's a C-channel, and not just angle iron, then maybe the bowing and bending board method might be needed.
Me? With a grinder, cutting torch, and welder, I would sure look into removing the obstacle for board replacement, and re-installing. That's been my solution for a couple of small trailers.

Apitong shiplap decking. No worries for 25-30 years

I just did this on my trailer last year. The back piece holding the wood in place on the trailer is most likely removable, at least it is on my two trailers. The only tools you should need are a Skil saw, a drill to drill holes and screw in floor screws, an angle grinder or oscillating saw, crowbar and hammer. My 14' trailer took about 3 hours to get the old floor out and a new floor in, this was with at least 50% of the screws needing to be cut off. If most of your screws come out easily then you should be able to get this done in less than two hours. One thing you may consider is using wider boards than what was originally used on the trailer, I used 12" boards instead of the 8" boards it came with.

If the bend the board method doesn't work easily after 5 minutes(it never has for me on any of the countless trailers I've done or helped with) just removed the end C channel & weld it back on after you replace the boards.

if you have a McCoys near, they have better selection of long treated lumber with better prices than Home Depot.

Good stuff in here. I've got this project on my list for the spring as well. How do you fix the open end with a board or strap? I was planning on having my wife or buddy stand on it while I worked the jack?

The bend the board method is what I used to replace all of the boards on my 20' decked Big Tex trailer. Once I figured it out it went pretty easily. I would think you could do it on the 18' but not on the 8' trailer. On smaller trailers I've always cut the piece of angle iron off the back and put the floor in and then welded the angle back on.

Edit to add: I did in fact actually put the boards in correctly despite the picture looking like the C is facing the wrong way. I didn't know that was actually a thing but my paw paw taught me to do that years ago and I've always done it without really knowing why.

Edit to add: After looking again I apparently I did in fact put them in "incorrectly." My knowledge was to always put them in facing the same direction not necessarily with the C facing down. At least this was on a trailer that will pretty much always be sloped to the back unlike a deck that should be level.

mdt_2001 said:

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Where is best place to purchase 18'+ treated boards? Any of the big box stores carry?

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For things like this I get my wood from McCoys. I just find they have better quality pressure treated wood with less knots than other places

I just cut a board width tab in the side of one C channel where a section of it could be bent up, then dropped the boards in one at a time there and slid them to the side either way until the last board went down at the tab location, then bent it back down and drilled a hole and put one screw in there to keep it secure. In the future I can repeat the process to quickly replace the boards again.

Super easy.

MouthBQ98 said:

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I just cut a board width tab in the side of one C channel where a section of it could be bent up, then dropped the boards in one at a time there and slid them to the side either way until the last board went down at the tab location, then bent it back down and drilled a hole and put one screw in there to keep it secure. In the future I can repeat the process to quickly replace the boards again.

Super easy.

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yes, may already find this situation toward the middle of the bed at the rear. Makes it workable on the shorter trailers where there's not enough length on the board to flex.

AgySkeet06 said:

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mdt_2001 said:

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Where is best place to purchase 18'+ treated boards? Any of the big box stores carry?

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For things like this I get my wood from McCoys. I just find they have better quality pressure treated wood with less knots than other places

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A couple of thoughts for whatever they are worth... I own a lumberyard. Agree that McCoy's carries a good product if you are near one. They are a good company.

For the 18' trailer, if you can break it up to using a 10' and 8', you will save money. Usually, lumber over 16' carries quite a premium. Not always but it is normally higher than combining a 10' and 8'.

Finally, and this goes against most thought -- many times I do not use treated lumber for my trailer beds. Treated tends to crack a lot more than yellow pine and I choose to just use yellow pine for trailers. (Also for the picnic tables we sell. I just don't want food on treated products.) You will get some more use with treated. But, I don't like the cracking. That, along with the higher price of treated, and I just use dimensional yellow pine for most of my trailer beds.

I used to think that way until I literally fell through a trailer trying to walk across it from dry rotted boards that looked ok on top.

Just replaced the deck on my 14' trailer. Used the bend method with a hydraulic jack and a short section of a 2x4. Took me about an hour total, was way easier than I ever thought it would be.

Get new pressure treated wood - you want wood that is still good and wet as it is far easier to bend than wood that has had time to dry out some. My trailer was 10 boards wide with 2x8x14's, I think the first 6 I was able to get in without having to bend and the last 4 were the ones I had to bend. But they went in easy.

On an 8 foot trailer it may be more difficult and you might have to remove the flat bar on one side that holds the end in and re-weld it, but I'd at leas try to bend first and save yourself some work.

I looked at both when I bought my wood. Using treated over regular yellow pine cost me I believe $9 more.

My old deck was untreated yellow pine with some type of paint on it. My tractor fell through one of the rotted parts, and when I took the old deck off I was able to remove 3 or 4 boards without cutting them due to the extensive rot.

BrazosBull said:

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Lumberman refer to that as " bark side out". Very important in anything to be painted too. Bark side out holds the paint much better . Also treated decks.... bark side up eliminates almost all grain shell out and splintering.

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For us more simple folk we always said you don't want your boards to be smiling they need to be very sad!

Thanks for the pics on the 'bending the board' method. I've got this job in my future and I was wondering how they got those boards in there.

One question -- Can you do this by yourself? I'm wondering, after I've got the board bent and ready to insert into rear channel, whether I can slide it enough to 'catch' it inside that channel.

If so, are you just using your hands to slide it in, or some kind of gripper? It seems that the 4" x 4" piece in the center that is bending it upward would be putting a lot of friction on it and making it difficult to slide by yourself.

Obviously, it's no big deal, cause you've done it, but I'm unclear on that point. Thanks.

I replaced an 18 ' utility trailer floor with 6" c purling. easy with welder and cutting tools.

Ribeye-Rare said:

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Thanks for the pics on the 'bending the board' method. I've got this job in my future and I was wondering how they got those boards in there.

One question -- Can you do this by yourself? I'm wondering, after I've got the board bent and ready to insert into rear channel, whether I can slide it enough to 'catch' it inside that channel.

If so, are you just using your hands to slide it in, or some kind of gripper? It seems that the 4" x 4" piece in the center that is bending it upward would be putting a lot of friction on it and making it difficult to slide by yourself.

Obviously, it's no big deal, cause you've done it, but I'm unclear on that point. Thanks.

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Yes, i did mine by myself