What is exterior plywood called in real trade, and why does the name change from one market to another? Many buyers see labels like exterior grade plywood, exterior-rated plywood, Exposure 1, CDX, or marine plywood and assume they all mean the same thing. However, the stamp and bond class often matter more than the sales name. This guide explains the common terms used in the US, AU/NZ, and Europe, and then shows what truly makes exterior plywood different from interior panels.
So, what is exterior plywood called in real markets? You may see exterior-rated plywood, exterior grade plywood, Exposure 1 plywood, CDX plywood, marine plywood, or EN 636-3 plywood. These names often point to moisture bond and intended exposure. However, they do not always guarantee long outdoor life by themselves.
This article follows a strict buyer-first format. First, you will learn the common names by region. Next, you will see what makes exterior panels different from interior plywood. Then you will get a simple selection guide, common mistakes to avoid, and a purchase checklist you can use on every PO.
Quick answer: what is exterior plywood called?
In plain terms, exterior plywood is plywood made with a moisture-resistant bond and built for wet or outdoor use. Markets call it different names:
- US/Canada: “Exterior” or “Exposure 1” on the stamp; “CDX” as a common trade term
- AU/NZ: “Exterior plywood” (often tied to AS/NZS 2271), plus structural plywood and marine plywood grades
- Europe/UK: EN 636 classes, with EN 636-3 used for exterior conditions
If you remember one rule, use this: the stamp and bond class matter more than the sales name.
Key takeaways (save this section for buying)
- “Exterior plywood” is not one global name. It is a group of grades and stamps.
- “Exposure 1” often fits short-term weather during build, not long-term open exposure.
- “CDX” is widely used, but it is not a guarantee of true exterior exposure life.
- EN 636-3 supports exterior moisture conditions, yet you may still need protection.
- Glue bond is only one part. Core build, face type, edges, and install details decide service life.
- Always buy with a short spec line: bond class + standard + thickness + intended use.
What is exterior plywood called in the US and Canada?
North America relies heavily on grade stamps. These stamps show bond class, panel type, and often a performance rating.
Exterior-rated plywood (Exterior bond)
When a panel stamp says Exterior, it points to an adhesive bond made for repeated wetting and drying. Buyers often call this “exterior-rated plywood” or “exterior grade plywood.” If your panel will sit in open weather for a long period, this is the label you want to see on the stamp.
Exposure 1 plywood (jobsite moisture, limited period)
Exposure 1 plywood is also made with durable adhesives, but it targets moisture exposure during construction or similar short periods. In other words, it can handle rain delays on site, but it is not meant to live outdoors with full exposure for months or years.
CDX plywood (a common trade name)
Many yards sell CDX plywood as a general sheathing option. People often treat “CDX” like a true outdoor grade. That is where problems start. In practice, CDX often links to a face grade combination plus an Exposure 1-style use case. So, always read the stamp, not only the “CDX” label.
Buyer tip: If your project is permanent exterior exposure, do not accept a loose promise. Ask the supplier to confirm the bond class on the stamp and the intended exposure level.
What is exterior plywood called in Australia and New Zealand?
In AU/NZ trade, you will hear “exterior plywood” as a common name. Still, the safest buying method is to tie the product to the standard and the bond type.
Exterior plywood (often AS/NZS 2271 exterior use plywood)
For many buyers, exterior use plywood points to panels made for wet or weather exposure under AS/NZS 2271. This group often targets appearance and non-structural uses where moisture is present. That may fit many outdoor skins, hoardings, and protected exterior jobs.
Structural plywood (construction use)
If the sheet carries load, buyers often specify structural plywood rather than “exterior plywood” alone. Structural use adds strength and stiffness needs, not only moisture bond. As a result, the right standard and stress grade become part of the order.
Marine plywood (higher build control for wet use)
Marine plywood is also common in AU/NZ supply. Buyers choose it when they need better face quality, stronger build control, and more stable wet performance. However, marine grade still needs correct edge sealing and good install design to last outdoors.
Buyer tip: In AU/NZ, the words “exterior” and “marine” can be used loosely in sales talk. Therefore, confirm the standard, bond type, and use case in writing.
What is exterior plywood called in Europe and the UK?
In Europe and the UK, you often see “exterior plywood” described through EN 636 service classes.
EN 636-3 plywood (exterior conditions)
EN 636 groups plywood by use conditions: dry, humid, and exterior. For buyers, EN 636-3 plywood is the key term linked to exterior conditions. This helps specifiers match plywood to moisture exposure.
A practical warning for EN 636-3 exterior use plywood
EN 636-3 addresses use in exterior moisture conditions. However, it does not automatically mean the wood itself will resist decay in every outdoor setting. That is why many long-life exterior jobs still rely on design protection, coatings, or treatment as needed.
Buyer tip: Think of EN 636-3 as a moisture service class. Then decide what extra protection the job needs.
What makes exterior grade plywood different from interior plywood?
Now that you know the names, let’s cover the real build differences. These are the factors that decide how a panel behaves when it gets wet.
1) Glue bond and bond durability (the core difference)
Exterior panels use adhesive bonds designed to hold under wetting and drying cycles. Interior plywood usually targets dry spaces and short moisture events. Therefore, bond class is the first filter when you compare panels.
2) Core build and void control (strength and stability)
Exterior work often puts stress on panels through swelling cycles, fasteners, and handling. A cleaner core with fewer gaps supports better stiffness and fewer weak spots. In addition, stable core build helps reduce warp.
3) Face type: sheathing faces vs finish faces
Many exterior panels act as plywood sheathing. These faces are not made for furniture looks. They are made for build speed and structural use. On the other hand, some exterior jobs need a nicer face for paint or clear finish. That is where higher face grades or overlays help.
4) Overlay and film options for harsh exposure
Some exterior panels use overlays or film faces to resist water and wear. For example, film faced panels are common in concrete formwork and repeated use environments. The face helps, but edges still matter most.
5) Edges and cut protection (the first failure point)
Edges fail first. Water enters through cuts, screw holes, and corner hits. As a result, even a strong exterior bond panel can swell if you leave cuts unsealed or store sheets in water.
6) Decay risk and treatment needs (often overlooked)
Exterior bond does not stop rot by itself. If a panel sits in long wet contact, you must manage decay risk through design, ventilation, coating, or treatment where required.
How to read a plywood stamp and avoid wrong “exterior” grades
Many disputes happen because buyers order by a generic name. You can avoid most issues if you read the stamp in a set order.
Step 1: Find the bond class
Look for “Exterior” or “Exposure 1” in North American stamps, or a clear statement of exterior use class in other systems.
Step 2: Confirm the standard or system
Ask for the standard reference (example: PS 1 type panels, EN class, or AS/NZS class). This step keeps “trade names” from taking over the order.
Step 3: Match the panel type to the job
- Sheathing and framing jobs care about stiffness and rating
- Finish jobs care about face and patch limits
- Re-use jobs care about wear, edges, and handling
Step 4: Lock thickness and tolerance
Exterior work shows uneven thickness faster. For example, you may see steps under cladding or lines under paint. Therefore, you should confirm tolerance if the finish is strict.
PS 1-19 Structural Plywood standard
AS/NZS 2271 exterior plywood standard
How to choose exterior-rated plywood for your project (simple guide)
Use this five-step guide. It fits most buyers and most markets.
1) Define the exposure level
Ask one clear question: will the panel live outside, or will it be covered later?
- If it is jobsite weather only, Exposure 1-style panels may fit.
- If it is long-term outdoor exposure, ask for Exterior bond or the correct exterior class.
2) Decide if the panel carries load
If the panel is structural, do not buy by “exterior” alone. Confirm the structural grade and design need.
3) Choose the face based on finish
- For hidden sheathing, face looks matter less.
- For painted panels, smoother faces save labor.
- For hard wear, overlays can help.
4) Plan edge and cut sealing
Edge work is not optional. In addition, many outdoor failures come from cut edges left raw. If you cut on site, keep a sealing plan in your scope.
5) Confirm storage and install details
Even the best sheet fails if you store it wrong. Keep stacks off the ground. Cover them. Allow airflow. Then install with correct gaps, fasteners, and drainage paths.
Common exterior plywood uses and what to specify
Different uses push you toward different names and grades.
Exterior wall and roof sheathing (plywood sheathing)
This area often uses rated sheathing and common trade grades. Here you should focus on bond class, thickness, and structural rating. In addition, install details matter: nail spacing, panel gaps, and weather wrap timing.
Outdoor cladding backers and hoardings (exterior use plywood)
For non-structural exterior skins, the buyer often cares about face quality, paint finish, and flatness. Here, “exterior use plywood” plus clear face grade is a safer order than a vague “outdoor plywood” request.
Concrete formwork and wet-cycle re-use (formwork plywood panels)
Concrete work is a special case. It is wet, abrasive, and fast. If you also buy formwork panels, you can link your exterior plywood knowledge to your formwork buying plan. For reference, see our internal hub on formwork building materials and our premium panel option: ROCPLEX Xlife formwork plywood.
Outdoor furniture and DIY exterior builds
Here, buyers often assume “exterior plywood” means “no maintenance.” That is rarely true. Choose a suitable grade, then seal faces and edges, and design for drainage.
Mistakes buyers make when asking “what is exterior plywood called?”
These mistakes show up in claims, callbacks, and early failures.
Mistake 1: Buying by nickname (CDX) instead of stamp
CDX can be fine for many jobs. However, it is not a universal promise of long outdoor exposure life. Always use the stamp and bond class.
Mistake 2: Treating Exposure 1 as permanent exterior
Exposure 1 handles short weather events well. Still, it is not the same as true exterior use in many cases. Choose the grade based on service life, not short-term survival.
Mistake 3: Ignoring edges and cut sealing
Edges are the weak point. If your crew cuts panels on site, plan sealing. If you do not, swelling will start at the edges.
Mistake 4: Thinking exterior bond prevents rot
Exterior bond helps the glue line stay intact. It does not stop decay in wet contact. You still need good design and protection.
Mistake 5: Skipping clear PO wording
Many disputes happen because the PO says “exterior plywood” only. A short spec line removes that risk.
Purchase checklist and spec wording (copy and use)
If you want fewer disputes, add a short spec line to every order. Here is a simple format:
[Standard / system] + [bond class] + [thickness] + [sheet size] + [panel type] + [face grade] + [use case] + [packing]
Use this checklist before you approve any quote:
- Confirm the panel’s market name (exterior grade plywood / exterior-rated plywood / EN 636-3 plywood / marine plywood)
- Confirm the standard or class used to support that name
- Confirm bond class and intended exposure level
- Confirm thickness and tolerance needs
- Confirm face grade and patch level (if finish matters)
- Confirm edge sealing plan (factory edges and cut edges)
- Confirm packing for transport and storage
If you source for export and need stable repeat supply, ROCPLY can support program orders with consistent build control and clear packing. If your use case includes wet-cycle re-use, you can also compare against formwork-grade panels such as
<a href=”https://www.formwork-plywood.com/3-ply-yellow-formwork-panels/” title=”3-ply yellow formwork panels”>3-ply yellow formwork panels</a>
to align your stock plan across projects.
FAQ: What is exterior plywood called?
1) What is exterior plywood called in the US?
Most buyers look for “Exterior” or “Exposure 1” on the grade stamp. “CDX” is common in trade talk, but you should still check the stamp.
2) Is exterior grade plywood the same as marine plywood?
Not always. Marine plywood is often a higher build level with tighter face and core control. Yet you still need sealing and smart install details outdoors.
3) Can I use Exposure 1 plywood outside?
It can handle weather during construction. However, for long-term open exposure, you should confirm a true exterior bond or an exterior class that fits the service life.
4) Does exterior-rated plywood mean it will not rot?
No. Exterior bond supports glue durability in wet cycles. Rot control depends on design, protection, coatings, and in some cases treatment.
5) What is EN 636-3 plywood used for?
It is commonly specified for exterior moisture conditions in EU/UK markets. Still, long-life exterior use often needs additional protection steps.
6) What is the safest way to order exterior use plywood?
Order by standard/class and bond class first. Then lock thickness, face grade, and the real use case. This keeps names from being misread.
7) What face grade should I choose for outdoor paint?
If paint finish matters, choose a smoother face and control patch limits. In addition, seal edges and prime correctly.
8) Why do edges swell even on exterior grade plywood?
Water enters through raw cuts and corner hits. Seal cut edges fast, store sheets off the ground, and avoid standing water.
9) Is “WBP plywood” the same as exterior-rated plywood?
WBP is a common trade term. It can point to a water-resistant bond, but it is not always a full grading system by itself. Ask for the standard and test basis.
10) What should I do if my use case is mixed (sheathing + wet areas)?
Split your spec by use. Choose a sheathing grade for covered work. Choose true exterior bond or higher protection for exposed work. This reduces risk and cost.
Final thoughts and next step
So, what is exterior plywood called? It depends on where you buy. In North America, the stamp often shows “Exterior” or “Exposure 1,” and many people use “CDX” as a shortcut. AU/NZ, “exterior plywood” often ties to AS/NZS exterior use standards, while structural and marine grades cover heavier needs. In Europe, EN 636 classes—especially EN 636-3—are common for exterior moisture conditions.
Next step: write down your real exposure level and service life. Then buy by bond class + standard + use case, not by a nickname. If you want a fast spec line for your next PO, send your country/market, application, and whether the panel will stay exposed. I can draft a clean purchase wording that your supplier cannot misread.
Post time: Apr-16-2023