# Car trailer needs a new floor



## jeromehdmc (Dec 31, 2011)

I have an old car trailer that is needing the floor replaced. I know someone can help me with a few questions.
It is 16' long and about 82" wide.
Should I go with 10" or 12" wide boards?
Should I get treated lumber or regular boards and waterproof it myself.
If I can find a sawmill locally would it be better to get them to cut me some boards?

Larry


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## Pallet Pete (Dec 31, 2011)

I built my trailer of similar size out of pressure treated decking boards that are 6" wide by 1" thick. The top is covered with deck stain to prevent sun cracking it has held up very well and is extreamly strong. I do not use it for cars however it is for firewood and my motorcycle.

Good luck 
Pete


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## rwhite (Dec 31, 2011)

If your going to use treated I would use the brown treated rather than the green. Don't completly understand the chemical difference (or if there is one) but it does seem to be a higher grade lumber, maybe doug fir instead of spruce or w-fir. But I really don't see the need for treated. It is designed for constant contact with soil or concrete to prevent rot or insects exposed wood may grey but rarely rots where it can get air. Iwould use 10" board and that should give you enough room to allow 1/4 or so between board so water can drain and expansion.


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## shmodaddy (Dec 31, 2011)

rwhite said:
			
		

> If your going to use treated I would use the brown treated rather than the green. Don't completly understand the chemical difference (or if there is one) but it does seem to be a higher grade lumber, maybe doug fir instead of spruce or w-fir. But I really don't see the need for treated. It is designed for constant contact with soil or concrete to prevent rot or insects exposed wood may grey but rarely rots where it can get air. Iwould use 10" board and that should give you enough room to allow 1/4 or so between board so water can drain and expansion.



I have never seen treated wood expand. Most SHRINKS dramatically while drying.  Water sealer will help you get the longest life out if your lumber on a trailer.


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## Pallet Pete (Dec 31, 2011)

The green and brown are rated for something like 100 years and the blue is 40 I believe this is why they use for home foundations now. It also shrinks a bit from sun light shmodaddy is correct about that it is the reason I use decking sealer on the top of mine. You wont need to worry about the bottom as it dosent see sun and it is alredy water treated.

Pete


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## Dix (Dec 31, 2011)

I've got pressure treated in the horse trailer.

I figure if it can take that urine/manure beating, it's good


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## rwhite (Dec 31, 2011)

shmodaddy said:
			
		

> rwhite said:
> 
> 
> 
> ...



Not real clear in my first post: You should leave a gap for untreated wood. If it is tight together and gets wet it will expand and the edges swell up or the board bows in the middle. 

Just read up a little on pressure treated wood and from what I can gather I have never used or seen #1 structure grade treated. Apparently what is sold in most stores is #2 and is made from the sapwood of pine, spruce, or w-fir due to the ease of chemical absorbtion. Also most of this wood is not kiln dries after treatment hence the warping etc. It stated the there is #1 structure grade treated lumber made from doug fir or hemock that is available just finding it may be more difficult. So I would say that given a choice of the cheaper treated wood or untreated I would go with untreated or even cedar if you could find it. The structural grade #1 seems like it would be a good choice if you can get it.


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## Pallet Pete (Dec 31, 2011)

rwhite treated lumber is full of moisture from the treatment chemicals you have to let it dry after install for a month or so in the sun some of the moister then evaporates away and it shrinks a little. The slimy feel on the lumber when you go to a lumber yard is actually excess moister from the treatment process.  After it shrinks a little you can seal it and then you have to seal every couple of years so it will be protected from the sun and last longer.

Pete


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## semipro (Dec 31, 2011)

ACQ (alkaline copper quaternary) treated wood can be very corrosive to metals, that is, your trailer rails and fasteners.


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## EatenByLimestone (Dec 31, 2011)

I would just get roughsawn wood.  Pine or whatever.  Just vary thickness to whatever your need is.  I wouldn't worry about treating it since spaces between the boards will allow them to dry out.  How may dock decks and barn sides have lasted decades without any coatings when exposed to the sun and weather.  Pressure treated will only add to the weight of the trailer which lowers the weight you can carry.  Also, the air moving around the trailer makes the PT unnecessary.  

Matt


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## Agent (Dec 31, 2011)

Ditto on the roughsawn if it's available.  I'd also stick with something in the 8-10" width.  Any wider and you'd be dealing with alot of boards cupping or splitting.  
You can also oil soak your floor for a waterproofing, just make sure it's dry first.


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## jeromehdmc (Jan 1, 2012)

You're right about the treated lumber being heavy, I didn't think about it.
I might try and see if there are any mills around that I can get the boards from.
If I do get them from a mill should I fit them tight because they aren't "seasoned" yet and will shrink up?


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## EatenByLimestone (Jan 1, 2012)

Never fit them tight.  The air movement around the wood is what keeps the boards in good shape.  If water and pine needles, etc can get jammed between the boards it will eventually lead to rot.  Shrinkage will depend on wood species and how the grain is oriented.  Vertical grain will shrink less in width than horizantal grain.   Also, if you fit them tight you will need more wood to cover the space.







Matt


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## JustWood (Jan 1, 2012)

Roughsawn for sure.
You can get oak now for the price of soft wood. Oak markets are terrible now.
 That trailer isn't going to make it 40 years anyway.


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## Deuce95ci (Jan 1, 2012)

Rough sawn on my trailer, the wider the board the more chance in the board cupping.


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## EatenByLimestone (Jan 1, 2012)

Who is selling Oak for the price of rough sawn softwood?  

Matt


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## JustWood (Jan 1, 2012)

EatenByLimestone said:
			
		

> Who is selling Oak for the price of rough sawn softwood?
> 
> Matt


You shou;d be able to buy green 2 common 4/4 oak at any mill in the country right now for $.50/bd ft. Maybe even 1 common if you flashed cash.


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## Giles (Jan 1, 2012)

Five years ago, I installed a new floor in my 14' equipment/tractor trailer. I purchased more then enough rough sawn white oak. Six inches to twelve inches wide, in various lengths. Most was one inch to one and one eight thick.
I bought more then needed because I had other projects but could have figured what length I needed for the floor and just purchased that.
Once or twice a year, I saturate the floor with used motor oil--dont tell the EPA
My trailer has to set in the weather and the boards show no signs of deteration or deformation. After a couple of rains, no oil is visable and the boards don't seem to be slick.


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## amateur cutter (Jan 1, 2012)

Giles said:
			
		

> Five years ago, I installed a new floor in my 14' equipment/tractor trailer. I purchased more then enough rough sawn white oak. Six inches to twelve inches wide, in various lengths. Most was one inch to one and one eight thick.
> I bought more then needed because I had other projects but could have figured what length I needed for the floor and just purchased that.
> Once or twice a year, I saturate the floor with used motor oil--dont tell the EPA
> My trailer has to set in the weather and the boards show no signs of deteration or deformation. After a couple of rains, no oil is visable and the boards don't seem to be slick.



+ 1 on the rough sawn white oak. I used 2 X 10's 10' & 6' so the seam is nearer the rear & easy to swap boards if one goes bad. Had to trim the ends slightly to fit in the grooves as the trailer was built for finished lumber decking. Used oil coating thru an old 3 gallon garden sprayer once or twice a year. Note I do park it over a tarp so it doesn't drip onto the ground while spraying. Makes a very solid & long lasting deck. A C


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## Wooderson (Jan 2, 2012)

Talk about heavy... My FIL and Uncle installed a 16' floor from 3" oil soaked red wood that had been previously used for bridge trusses.  No telling how old and no signs of decay.  I bet I won't have to replace it in my lifetime.


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