“I’m building a new trailer and I’m wondering about what deck material to use? So many choices, all with various advantages and disadvantages. I probably don’t even know all the available choices. How do I decide?”
We get this kind of a question once in a while, so here is an article to explore possibilities. I don’t have a firm answer, because every situation is different. Yet, we can certainly discuss some deck options and list some advantages / disadvantages for each. We can also talk about where some work better than others. Hopefully that will give you power to decide what works best for your situation.
What Does YOUR Trailer Deck Do?
Is that a silly question? Maybe, but the first step in deciding about the right trailer deck material is understanding the need. What does your trailer do? What ‘should’ it do, and what ‘should’ it NOT do? Here are some thought starters.
- Does your trailer carry rocks and dirt?
- Does it carry something with wheels? A motorcycle? ATV’s? A side-by-side? A Jeep? A tractor? A car?
- Is the trailer open? Or enclosed?
- Must the deck be waterproof? Or can it allow flow through? Or does it even matter?
- Does your trailer tilt (like to dump the load)?
- What traction does the deck need?
- What weather does your trailer deck see? Does it live outside? Or in a garage? Is it covered? Or open and exposed?
Think about the above while you read through the various deck options – advantages and disadvantages below.
Options For Trailer Deck Material
Numerous options exist, more than we can reasonably discuss individually. So, we’ll break the options into general categories and talk about them that way. We will discuss some specifics of certain trailer deck materials, but not all.
This is a broad category that includes plywood, sheetmetal, various plastics, etc.. Sheet works really well if you are carrying sand, dirt, yard stuff, etc. because it holds the small bits from passing through. And, it is easy to sweep off to clean. Likewise, for an enclosed trailer, sheet material keeps the outside out.
Plywood is the most common because it is very adaptable, and one of the least expensive. It’s easy to install because bolts or screws are easy to place through it. The big drawback with plywood is weather. Even the treated plywood doesn’t hold up to weather very well, so you may need to replace the deck once in a while.
This material on a trailer deck requires regular maintenance (paint or other finishes) to keep it nice. Keeping it under a cover is a big plus too.
Enclosed trailers often have plywood floors since it’s makes a smooth, flat deck material. And, the enclosure keeps the weather out, mostly.
There are some great non-wood sheet materials that work well for a trailer deck too. Nyloboard (may be out of business) is on of my favorites. It is more expensive, than plywood, but acts very similar. Nyloboard is nylon and fiber which is brutally tough, and waterproof.
There are some other hard-ish plastics or plastic mix materials that do OK, but most plastics are too soft as a trailer deck material. They will scratch easily with scraping loads.
Steel sheet is also a common trailer deck material – especially tread plate, aka diamond plate. This is often much more expensive than plywood, and for similar strength, usually heavier. (Typical is 2 to 4 times heavier – depending on what you are comparing it to.) It looks nice and is very robust. It can be bolted down or welded to the frame.
Choose the right thickness so it won’t bend down between the cross members. Nothing worse than a trailer deck with ripples because the material is too thin for the load.
The hiccup with steel is corrosion. Paint it well, but even at that, the paint can scrape off and leave areas for rust. (Like for a dump trailer, it is hard to avoid.) Often it is fine in dry climates, but can be problematic it wet areas.
Aluminum is better for corrosion, and it is much lighter. (1/3 of the weight of steel for the same thickness.) However, it is not as tough, so up-size the thickness just a bit, then expect gouges and scrapes. At least it won’t rust in those scrapes.
Aluminum plate works great for many trailer decks, even over a steel frame. When you bolt it on, make sure to isolate steel from aluminum (or you’ll get galvanic corrosion). Anyway, putting a thin stip of rubber between the steel frame and the aluminum sheet will usually solve the problem. We recommend painting the steel frame first, then the rubber strip, then use Stainless Steel bolts to complete the isolation.
One minor detail with metal decks – they tend to be really loud. The metal acts as an amplifier for bumps. Contrast that with wood, which tends to dampen the noise a little. If quiet is one of your objectives, wood might be a better choice.
Wood is the most common plank material, and in particular 2-by dimensional lumber. This also comes in treated, non-treated, hardwood or redwood. We don’t recommend redwood as it’s not a structural lumber. Of course, it’s certainly strong enough for many trailers.
I’ve seen 5/4 (five-quarter) and “tongue and groove” plank work too.
Plank deck trailers are popular for equipment hauling. Also, for larger trailers like Car Haulers and Deck-Over trailers.
For lighter duty trailers, the plank deck tends to be heavier than needed, but it does look nice. This works well for tilt top trailers and those that take some abuse on the deck (like hauling rock or concrete).
Like all wood, it looks best when it’s new because the weather, and work, will take a toll.
There are non-wood plank materials like Trex that some people like. That’s good if the load is relatively light and the trailer deck is not abused, but these plastic style planks don’t take abuse well. Please don’t choose Trex (or other plastic plank) for applications where the deck will see a lot of abuse. (Yes, like hauling large / sharp rock.)
Interlocking metal plank is also a nice possibility. The pieces slide together or hinge together to make a connected floor. It comes in various materials like aluminum extrusions or fiberglass, and with various textures for traction. This stuff is more common for walking on, than for driving on, and not so common as a trailer top deck. It is worth mentioning, however, because it does show up once in a while.
Expanded metal is technically sheet, but we’ll treat it separatate because it is not solid. Yes, expanded metal is great for as a trailer deck material – if the circumstances are right. Also think about it in terms of the folding tailgate, ramps surfaces, etc.. There are many places where this discussion is applicable.
There are 2 common types of expanded metal sheet – flat and raised. They both have good traction for both wheels and shoes, but especially the raised (non-flattened) style.
There are 3 issues with Expanded Metal:
- Dips that can develop between the cross members if you put something heavy there. Even walking while carrying something heavy? I’ve actually seen it more when driving something onto the trailer like motorcycles, side-by-sides, etc. that have a high localized force. Just make sure the expanded metal is stiff enough for your application (or support it more).
- Expanded metal is hard to finish well. Because there are so many little features and tight inside corners, expanded metal does not paint well (primarily because it’s so hard to clean properly). It also does not hold the paint well with things rubbing over it (because everything is a corner so paint likes to scrape off).
- Don’t fall on it, especially the raised patterns. All those edges, are not kind to skin if you scrape on it.
I should point out that the bending or “dips” are not a safety concern. The expanded metal will handle a lot of load far beyond where it starts to expand more and take a permanent set. (Some people call it hammocking.) The dips are mostly aesthetic, and annoying.
Expanded metal comes in a lot of different thicknesses from about 14 gauge up. It also comes with different size holes (rated by hole size and % open), and in flat or traction formats. I don’t know which format is more resistant to “dips”, so that’s worth asking your supplier. That said, the lower % open means more material per square, so it tends to be stronger. Also, the orientation of the holes definitely makes a difference in its resistance to “dips”.
A Deeper Dive With Expanded Metal
Because this is a not so uncommon topic of discussion, we are going to do a deeper dive into expanded metal. Also, since we suggest expanded metal as an option for many of our trailer folding tailgates (that also act as a ramp), it is important.
For choosing the right expanded metal, I recommend a discussion with the supplier about your application. Here are some things to consider.
- Flattened is easier on the skin if you come in contact. Also easier to finish (paint) and keep it nice.
- Raised expanded metal is better for traction. When installing, orient it to maximize traction, if that is a concern.
- One rating of expanded metal is % open. If it is 60% open, then 40% of every square is metal, and 60% is air.
- Thicker material is stronger, but also heavier, and more expensive. The same for lower % open.
- Smaller opening size has less tendency to stretch and ‘hammock’. Same for lower % open. Thicker materials also resist bending more, but often don’t come with small openings. Resistance to ‘hammocking’, it is a balance I am not completely qualified to address. Ask a supplier about your situation.
- Put supporting bars under the primary load paths. If you will load a wheeled vehicle, support the areas of expanded metal under the wheel path. If part of the tire is above the bars, the strength requirements for expanded metal are less.
- Add extra support bars if needed. It might be lighter and less expensive to add a couple bars than to have extra thick expanded metal.
Again, the most important thing when choosing expanded metal is to ask the supplier. Talk about how you will use it, and what materials they carry.
This might be a little controversial as a category because it overlaps several of the other categories. For instance, traction plate (also called Diamond plate) certainly fits the category “flat sheet”. And, the traction versions of expanded metal fit that category. However, for certain types of trailers, there are other traction products like Grip Strut or Perf Grip that can be useful. (See McNichols.com for a variety.)
Material with traction features offer a nice advantage for a trailer deck that handles loads with wheels. And good for walking on. They are often not so great for loads like dirt because most have holes through.
What Have We Missed?
The above covers a pretty wide variety of trailer deck material. It certainly covers the most common ones. But, what have we missed? Do you know of another common material that we should include?
Most of the Trailer Plans at Mechanical Elements offer a variety of trailer deck material options. Most include Plywood (in either single or double layer), plank, and metal sheet. Many of our folding tailgates show expanded metal for the tread.
The single layer plywood is great for quick installation, however, using a double layer of plywood of half the thickness gives a more rigid final deck. Stack the sheets like overlapping bricks, then glue it all together. The result is a one-piece deck, even for a large trailer. That one piece helps distribute the loads, and stiffen the total trailer.
Plank options include choices for board width, as well as fastening. Some people prefer bolts through the deck. However, for those people that don’t want to see the bolts, we have a nifty solution for that too – in the plans.
That’s It. Please feel free to include your thoughts in the comments. I read them all, and I also respond when appropriate. Thank You!