Lumber Choices for Trailer Decking
White Oak is the top choice for decking a truck or trailer, but other woods get some votes in this thread. March 4, 2009
Question
I have a customer who would like me to mill some decking for a heavy equipment trailer. The trailer would remain outdoors. I know white oak would be a suitable choice but I don't have any on hand. What other species would work?
Forum Responses
(Sawing and Drying Forum)
From contributor G:
What do you have available? For carrying tracked vehicles, we sometimes use live oak.
For carrying rubber-tired vehicles or static loads, treated southern yellow pine is fine.
From contributor F:
Douglas fir is good as well.
From Gene Wengert, forum technical advisor:
What lumber do you have available? Can you trade it for some white oak? If not, buy some white oak or treated southern pine. Has your customer calculated the sizes needed and the frame spacing? For heavy equipment, it is critical to avoid a failure as a failure can be very expensive.
From the original questioner:
I have some elm and hickory on hand. I'm not sure about the rot resistant of hickory or elm. He will use the trailer for equipment with rubber tires. I'm not sure how long these species will last outdoors.
From contributor S:
The best decking around here is VG fir. If you can get access to some good size softwood logs you could use the short cut method of quarter sawing. Most equipment trailer decking that use softwood is six inches wide and two inches thick.
From contributor R:
Hickory will work fine, just about any wood will as long as it doesn't have ground contact or doesn't stay wet for long periods. Don't park it under trees or allow debris to build up on it.
From Gene Wengert, forum technical advisor:
Two dominant issues (after availability) are strength and decay resistance. Density is a good indicator of strength. Perhaps it is a surprise the q-sawn (or vertical grain, vg) is as strong as flat grain. With a trailer, although much of the wood will dry out after a rain, certain areas, such as where bolts are or wood in contact with a framing member will not dry out quickly and so you will need a decay resistant wood or treated wood. Even slightly decay weakens the wood. As the cost of having a failure is so high, you do not want any decay. Hence, heartwood of white oak or DF, or treated SYP are your only choices.
From contributor R:
Those species would be a better choice for decay resistance but they are definitely not the only ones. I have one customer that uses cypress only on heavy equipment trailers, lowboys, and etc and has no problems with strength or decay. I have another one that uses red/white/live oak, gum, hickory etc and he has no problems with decay. I have used red oak (laurel oak) on my own trailers and one is going on 15 years with no problem. I use it every week and haul a minimum of 10 tons. I have one that has heart longleaf pine (with heavy pitch) that's going on thirty years with no problem. I have one with hickory 2" thick that is about eight years old and the only problem with it is I pulled one of the boards lose from the strap with the grapple.
From the original questioner:
Thanks for all of your replies. I'm not sure what I'm going to do yet. I will need to chat with the customer.
From Gene Wengert, forum technical advisor:
Old growth cypress does indeed have decay resistance. It’s very pricy, so I did not include it when there are cheaper choices. Live oak is also a good choice, but hard to find and can be pricy.
Apparently you are able to keep your trailers dry enough to resist decay, but because not everyone will be able to do that, it is better to use a wood with natural decay resistance or one that is treated. If wood is kept dry, it will not decay. A wood like gum is too weak compared to the others. Hickory does not have enough decay resistance. Heart longleaf pine is great (high strength and good decay resistance) but it is too valuable to use for a trailer; you can get the same service from treated SYP at half the cost.
From contributor R:
Sweetgum is plenty strong. It rivals loblolly pine in mechanical properties. Some buyers pay a premium for gum ties, sleepers and mats. Maybe a user could buy those products cheaper. Heart pine is a beautiful wood and has good value when you can sell it, but there is no way I could buy PT for less than I can logs, and using the lower grades for decking makes sense. I could use heart cherry, cheaper than I could buy PT for. Other concerns about PT, if it is ACQ, what about the cost of stainless or hot dipped fasteners and a added isolator between the decking and the frame?
From contributor G:
I'm surprised no one has mentioned apitong. It is considered the best by many truck and trailer manufacturers since it needs no finish because of the oils it contains.
From Gene Wengert, forum technical advisor:
Apitong is indeed widely used and is very good. My original listing was for North American species.
From contributor U:
Here on the Oregon coast most everything I cut for decking and dump truck side boards is a bastard spruce. The truckers tell me it’s really strong and light weight and they keep the word out to other truckers - I have cut lots.
From contributor F:
I agree with contributor R. In my area of western Washington we use "beach" spruce for trailer decking. It is tough and relatively dense.
From contributor A:
I would not use hickory. PPB's like it and it is not rot resistant at all. I have used black gum with some luck but mostly white oak, osage orange, black locust, heart pine, and even walnut center cuts.
From contributor Y:
Here in NH a lot of guys use red oak even though it has poor rot resistance. It usually gets trashed by the excavator tracks before it has time to rot anyway.
From contributor D:
Red elm is used a lot around Ohio and seems to have quite a bit of decay resistance. It is best to use heavy (thick) boards and bolt them down quickly since it does tend to warp.
From contributor I:
Have you tried redwood yet? It’s large and has a great snapping strength.
From Gene Wengert, forum technical advisor:
The original question was for decking for a heavy equipment trailer. Strength is a key along with modest decay resistance, as the trailer will be out in the open (no cover). Of the native North American species, white oak is the best. Incidentally, redwood is too weak.
From contributor Z:
Apitong is a hardwood and works great for heavy equipment, but it will rot in less than 10 years if not kept dry. Pressure treated pine will work great if you aren’t hauling machinery with metal tracks.
