Repainting Trailer and Replacing Trailer Deck

[BoylermanCT]

Since I am stuck at home for a while and the weather is turning nice, I've decided to repaint and replace the deck on my 6x10 trailer. My question is do I simply use 2x pressure treated wood for the deck, or would untreated douglas fir that I coat with preservative be better or something else like red or white oak? Its a single axle trailer rated at 3500 lbs, so I'm leaning towards pressure treated lumber. My other question is does it matter if I use 2x6, 2x8 or 2x10 for the deck? The current deck is 7 2x10's and one 2x6. I could do the same, or I could use 13 2x6's or a combination of any of them. Are 2x10's stronger that 2x6's or 2x8's? Or does it not matter. Using all 2x6's would cost $90. Using 2x10's with 1 2x6 would be $110. All tips or advice welcome. Thanks!

 

[i7win7]

I would use treated lumber the same size as the original wood. Then place the old board on the new one and use it as a pattern for the bolt holes. Also use new carriage bolts.

 

[redman135]

Hello BoylermanCT, In terms of deck strength, the limiting factors are timber thickness AND distance btween the cross members.
Cost wise you will notice that 6x2 timber is cheaper than 10x2 timber for the same area.
When you say "preassure treated" I assume you mean pine. If it is straight out of the teatment, there can be significant shrinkage leaving gaps between the boards. If you carry fine product like morter sand it may be a nuisance. If possible try to select drier boards to minimise the gaps between boards.

I can't comment on non pine board decking.
On my trailer I have gone for 2 thicknesses of plywood(pine) on the floor. How would this cost out for you?

 

[denchen]

If you want it to last, then I like many farmers use Keruing. (we pronounce it Kero-win). Its often used for cart bottoms or window sills. A word of warning, if you get a splinter, it WILL go septic, and, it soon takes the edge off tools. Other than that it should last for years. Or, although I`ve never used it, there are `boards` made out of reprocessed plastic waste. They last years without treatment, are easy to use and will outlive the bolts that hold them in.

 

[Hay Dude]

Doug Fir oozes sap. It may get on items you put in trailer or the bottoms of your shoes.
#1 PT pine is excellent. It doesnt have the larger, looser knots of #2 which tend to fall out, exposing the wood to weakening or further decay.

 

[Egon]

Treated lumber at whatever width. Suits you.

When it’s disassembled make sure it’s all cleaned up & painted with a rust coat paint. Also isolate the rails and deck boards with strips of rubber ??

Do not paint the finished wood product but stain if colour is required.

 

[KennyG]

Use PT and be prepared to do some clamping, wedging, or whatever to get them close to straight. I installed mine as tight as possible and, after drying, they have small gaps. Of course, I store my trailer inside. If you store it outside, you might want larger gaps. Look at the ring pattern and install all of them crown up. I used 2x6 and they are easier to fit. Technically, a larger board will have more load carrying capability for point loads, but that really isn't a concern for most people. One of the best things I did was install recessed D-Rings in the deck, bolted through to the frame cross members.

On mine I cleaned up the rust and primed and painted with Rustoleum. All brushed on on the frame and sprayed on the exposed parts.

 

[GLyford]

PT yellow pine or white oak. Red oak has pores that make it hold water and starts to rot quickly.

Since you are laying flat, the strength comes from the the thickness, not the width. When on edge like a joist or rafter, wider is stronger (think of it as very narrow and super thick).

I have used the urethane window flashing to separate steel from the PT chemicals with pretty good results. Comes in a 6" wide roll, usually in the same aisle as all the roofing stuff.

And same as for decks, use either hot dipped galvanized, stainless, or coated "PT rated" bolts or screws. The make a self-drilling, self tapping screw just for trailer decks.

 

[fried1765]

I would use treated lumber the same size as the original wood. Then place the old board on the new one and use it as a pattern for the bolt holes. Also use new carriage bolts.

The OP should use marine grade PT Southern Yellow Pine.
Material width dimension does not matter.
Standard grade (Lowe's/HD) PT is treated to .06 retention level.
Marine grade is treated to .60 retention level, TEN times the retention level of that sold at Lowe's & HD.

 

[s219]

I redid a trailer last year. It had used 2x6 "above ground" treated, but I changed to 2x10 "ground contact" treated. The wider boards worked out better for spacing -- was able to get the gap I wanted and did not need to rip any boards (when you cut or rip treated lumber, the exposed wood is no longer rot-resistant). So do the math on that to get the ideal board size among 2x6, 2x8, etc. Wider boards tend to be stiffer even when laid on the flat, which may be another consideration.

The trailer originally had the 2x6 boards jammed tight. I assume they had dry lumber in order to do that, since wet treated wood normally shrinks a lot when it dries. Despite my perceived benefit of having a tight deck, I found that it seemed to trap water and I think that contributed to rot. So when I put on the new boards I specifically put a 1/4" gap between boards and I am sure it opened up more as the lumber dried. I want that deck to drain.

I was able to find the self-tapping trailer deck screws at Lowes, which made it easy to put on the new decking. These screws are meant to self-drill through the wood, then self tap through the metal. I think they have a 1/4-20 thread. These screws had a nice coating on them and are supposed to be corrosion resistant and rated for treated lumber (the original screws were raw steel and had rusted badly).

After taking off the old rotten deck and all the old screws, I used rust converter on any parts of the frame with rust, then primer, then paint. Before I put the new deck down, I put strips of roofing felt (tar paper) over the top of the frame cross members. So that would prevent direct contact between the lumber and frame.

Here are some pics. This was a small 4x8 trailer, but I plan to do the same with my larger tandem-axle 7x16 soon.





Here's one of the old screws:

 

[BoylermanCT]

Thank you all for the info and advice. The trailer was originally built with self tapping trailer screws, and I plan to do the same with the new deck. Will be interesting to see what condition the metal underframe is in once the existing deck is removed.

Fried1765, where do you get marine grade PT pine? I am guessing the big box stores won't have it. Not sure local lumber yards will unless I call some down by the coast. I know the typical pressure treated boards are not very impressive. I had a pile of PT landscape timbers rot out in a few year as they were stacked in a pile resting on 2 cross 2x4's so they weren't touching the ground!

 

[two_bit_score]

I would use treated lumber the same size as the original wood. Then place the old board on the new one and use it as a pattern for the bolt holes. Also use new carriage bolts.

I would add to be sure to use the proper coated faster, galvanized or stainless as the case may be depending on the type of preservatives used on the boards. Recommend POR as a rust treatment then paint with any good topcoat.


Enjoy your project!

 

[sandman2234]

I am going a different route with my Big Tex 20 plus 5 trailer. The wooden deck has soft and rotten spots from being stored outside, and will need replacing very soon, if not before I use it again. I did some inquiring at places that I go to for tractor trailer repair and have found enough (combined with what I had already) to deck out my trailer in aluminum deck. Since I am still working 6 days a week, taking the time to strip it and replace it hasn't happened, and may not for a while but I have most of what I need. Hopefully this will be the last time I have to replace the deck! I may add a strip of wood between the aluminum for traction and occasional nailing of dunnage.
David from jax

 

[3Ts]

You don't need marine grade pressure treatment. And you're not likely to get it unless you are near the coast. You do need more preservative than typically found at a big box store - get the ground contact rated treatment level. As for fastners, just be sure they are ACQ rated and you'll be fine, these are typically hot dipped galvanized (not regular galvanizing), stainless steel, and many ceramic or proprietary coatings. The new chemicals in pressure treated wood are quite corrosive so do use a separator between the wood and frame. I would use something like the new window flashings that are self adhesive, have a type of rubberized material. They are self healing and provide better protection than tar paper.

 

[Hay Dude]

You don't need marine grade pressure treatment. And you're not likely to get it unless you are near the coast. You do need more preservative than typically found at a big box store - get the ground contact rated treatment level. As for fastners, just be sure they are ACQ rated and you'll be fine, these are typically hot dipped galvanized (not regular galvanizing), stainless steel, and many ceramic or proprietary coatings. The new chemicals in pressure treated wood are quite corrosive so do use a separator between the wood and frame. I would use something like the new window flashings that are self adhesive, have a type of rubberized material. They are self healing and provide better protection than tar paper.

Agree.
#1 PT is a real nice affordable option
Marine grade is for water submerged application

 

[Peter 315]

Any PT will work I just spray the deck down with boiled linseed oil and mineral spirits 50/50 mix once a year before winter I leave the trailers outside spray with ff and try to shovel the snow off ..... All the trailers I have seen don't have anything between the wood and steel .........

 

[fried1765]

Agree.
#1 PT is a real nice affordable option
Marine grade is for water submerged application

Depends on the definition of Marine grade.
Marine "splash" is .6 %
Marine "submersion" is 2.5%

Here are the ratings:

(#1 PT refers to the grade of the lumber, and has nothing to do with the level of preservative.)

Above ground .25%
Ground contact .4%
Salt water splash .6%
Wood foundation .6%
Salt water immersion/submersion 2.5%

In CT the OP should be able to find .6% at a dock install contractor (they would be using it for decking).
At the very least, "ground contact" material should be used for trailer decking.

 

[chim]

Speaking of pressure treated lumber, here are a couple pics from Saturday. I completed a new shed for the l4240 late in 2019. The wood deck pictured is from the oldest shed that we bought new in 1989. It sat there on a crushed stone pad till I pulled it out of the way to set a new shed around 2002. It's been sitting on dirt ever since. At that time I planned to burn the old shed, but came upon enough used steel to re-roof it and give it a few more years for overflow from the new shed. Last year we pulled it out of the way again. This time it was to build the newest shed that the L4240 would fit into:

https://www.tractorbynet.com/forums/projects/420084-found-piece-lawn-mower-shed.html

The unplanned vacation caused by CV-19 is giving me a great opportunity to catch up with work here. Last Friday I had all the stuff removed from the old shed and either tossed it or got it into storage. By Saturday all that remained of the oldest shed was the floor and its framing. By the end of the day even that was gone. Remarkably, the 4x4 sleepers that were under the shed looked as good as new. The closeup is the underside of one of them after a quick scrape with a flat shovel to get some mud off of it.

 

[herm0016]

I did my 16 ft. car hauler last year. 2x6 ground contact, and made it all tight. it has very nice 1/8 or less gaps now. used the coated self tapping screws and chalk lined across each of the frames. installed wood, used a ratchet strap at the frame to straighten up, drilled the 2 holes and then ran the self tapping screw in with a brace. most of the old screws were rusted in and broke off. so i drilled all new holes. the frames were cleaned up with a flap wheel and primed and painted. i had to rip an inch or so off of the 2 center boards.

 

[Sawyer Rob]

. I had a pile of PT landscape timbers rot out in a few year as they were stacked in a pile resting on 2 cross 2x4's so they weren't touching the ground!

Landscaping timbers are "dipped" , not pressure treated and that's why they rot fairly fast.

Check the tag on PT lumber, you want .60 treat, .40 won't last near as long, as it's not rated for ground contact.

You can spl. order .80 or 1.0 but have a FAT wallet to pay for them! (marine rating)

SR