Treated wood....brush with oil?

Im repairing a flatbed with some treated wood. Im wondering if it will help in the long run if the wood is brushed with some oil before assembly? The flatbed sits outside and paint doesnt seem to last well. Now days treated wood isnt the same treated wood from years past. If it was, I would figure on leaving it as is.

That would hurt nothing. Jim

I've got an 18 and a 12 foot flatbed trailer with treated wood floors. I paint both of them with oil occasionally. Do it on a nice sunny day and it soaks right in. Can sure see a difference in the way water beads up on it.

I don't think it hurts at all. Just wait until the treated is dry. That may take a while...like several months.

You should be able to order or source copper chromated arsenate .40 or higher pressure treated wood for ag and industrial purposes. The EPA did away with it for consumer/residential purposes and is why you can't get it "off the shelf" today. Very effective wood preservative, except at some point it was frowned upon for playgrounds, picnic tables etc. I think most would have an opinion to share as to its safe use, myself included.

If this is new material, then you likely have ACQ or whatever the current ground contact treated wood there is available. You should be able to leave it alone if you use the ground contact type. Ideally, install it and let it dry out in place, then use a wood preservative as needed or oil.

The thing is this wood is kiln dried southern yellow pine (at least out here its been this species for as long as I can recall) then it's put into a pressure vessel for preservative treatment. When it comes out it is high moisture. I have hauled more trailer loads of the old stuff than I can recall. Heavy, wet and curls up drastically if left out to dry in hot weather individually.

Like was said, applying oil works, but it must be like kiln dry to wick in properly. I'v done it in addition to creosote, it works well on posts in well drained soils. How you achieve that low moisture content and not have it warp is beyond me. If it does not wick in, you will have a guaranteed slick surface that is dangerous to walk on and or haul things on.

Most people are under the misconception that "treated wood" means that it will resist water. This is not true. The word "treated" refers to the wood's resistance against wood-boring/wood-eating bugs, as well as against some forms of fungi that can cause rot. This applies not only to the modern method of treating wood, but the older ways as well. So, it would be advantageous to also treat your decking to resist water as well, and oil is an old, time-honored way of doing this. Obviously you wouldn't want to treat the deck of your home with oil, but the wood of a trailer needs to withstand not only weather, but also rocks, road tar, and oftentimes road salt as well.

Linseed oil

Wait a year for it to dry first tho, then it will help a lot.

It depends on how the trailer is made and what oil you use. The trailer I have there is a piece of metal you weld to the trailer to hold the wood down. You sure wouldn't want anything flammable on the wood if you are going to weld on it. The treatment the wood has will protect the underside. It's the top side that needs sealing. I would go ahead and put the deck on and use a deck finish on the top and as much as you can get to on the edges and not worry about the rest. What happens is the sun dries out the surface to where the wood gets small cracks in it which allows water to penetrate. Treating the wood once or twice a year and the treated wood deck should last forever.

whem i built my wagon deck i just poured hyd. all over it.and brushed it in with a broom.

I agree, get the wood on there and bolted down before it drys out and warps. You also want the crown of the end grain up so the wood will naturally shed water.

Then let it dry about a month before trying to put anything on it.

A lot of very good information, most I didnt know. Thank you all for your replies. It seems a lot of wood now days warps quicker than it used to.

My 6x16 flatbed trailer is pushing 40 years with it's second floor; sat outside all it's life. First was OEM yellow pine, 2x10's. Second was my doing and was 2x6 (way cheaper than 2x10 for the same area) treated and coated with Linseed and turpentine 50-50 (turpentine thins the oil and allows it to penetrate better then evaporates). Non-periodically....when I felt the need, I'd top dress it with more 50-50. Today it will resist a sharp knife after about ?" penetration if in heart wood and not a sap line.

Hi Steve, yes the crown up and I have done that but it doesn't seem to guarantee cupping won't happen in the other direction, at least that's my experience. A friend of mine builds decks for a living. When he uses 6' or 8" decking (not for 4" wide stuff probably), he cuts a saw kerf about 1/2 way through the board thickness (so say 3/4" into a 1 1/2" thick deck board) down it's length on the bottom side. Then he screws or nails the deck boards down. The saw kerf enables him to really anchor that board down flat and cupping never seems to happen regardless of crown up or down.

There was a time when it was common practice to lay decking boards with cup facing up, so as to have a natural runoff. That line of thinking was later ditched on the argument that if a board is "properly" secured in place, then the act of "properly" securing it would straighten out any cup-down boards and provide a flat deck. IMHO, I still believe it is better to take the time to place the boards with cup up. In "my" pea-brained mind, it's worth not having a truly flat and perfect deck if it means the deck will have a longer usable life. The more that water sits on lumber, the shorter the lifespan of that lumber - generally speaking, of course, as most people do not upkeep their wood as it's meant to be.

From the contractor/builder's point of view, it's best to just throw the boards down and get the job done as quickly as possible, then move on to the next job. Enough has been argued both for and against to where most building codes (all that "I" know of) no longer specify anything about the cup facing up. But then again, building code doesn't mean that's the best it can be. Mike Holmes said it best when he would explain how building codes are "[i:d3a8ed7648]minimum acceptable quality[/i:d3a8ed7648]". ...To the best of my knowledge, there isn't any specifications concerning trailers as to whether cup should face up or down.

To sum it up for you, and the answers are below, the treated wood is only treated for bug resistance. Not for water resistance. The best thing you can do is to wait for about a year, or until you notice it drying out, then put the boiled linseed oil, with a little thinner on. It will soak right in. You will do no good if you do it green. Good luck - Bob