Engineered wood
Panels fail at the glue line, and the glue line is the one thing you cannot see.
Plywood, MDF, OSB and particleboard are bought on thickness and price and returned on bonding class and formaldehyde emission. Two panels of identical dimension can be built for entirely different service conditions, and the difference is invisible until the first wet week.
The programme
Four panel families, and one beam.
Panels from European production, in the grades and thicknesses the order calls for, with the certification that lets them be used where they are going rather than a generic mill certificate.
- Plywood
- Birch and combi construction, standard and film-faced, plus flooring grades for transport bodies and interiors, and LNG cargo-containment insulation grade. Thicknesses, ply counts and face grades to order.
- MDF
- Medium-density fibreboard for furniture, joinery and interior fit-out. Standard, moisture-resistant and fire-retardant types, raw or faced.
- OSB
- Oriented strand board in the four EN 300 grades, for sheathing, decking, packaging and site use.
- Particleboard
- Chipboard in the EN 312 type range, raw and melamine-faced, for furniture and interior applications.
- H20 formwork girders
- Glued timber I-beams, plywood web and softwood flanges, to EN 13377 — a full technical page of its own: Formwork Girder H20.
The two numbers that matter
Bonding class and service class are different things, and both get quoted as “WBP”.
One describes the glue's resistance to water in a laboratory test. The other describes the conditions the finished panel is fit to live in. “Waterproof” and “exterior” are marketing words that map onto neither precisely, and they are the words in most enquiries.
| Standard | Class | What it means |
|---|---|---|
| EN 314-2 | Class 1 | Dry conditions. Interior use, no risk of wetting. |
| Class 2 | Humid conditions. Protected exterior, short-term weather exposure. | |
| Class 3 | Exterior conditions. The test regime includes boiling; this is the class behind the phrase “WBP”. | |
| EN 636 | EN 636-1 | Dry conditions. |
| EN 636-2 | Humid conditions. | |
| EN 636-3 | Exterior conditions. This is the class specified for formwork and for structural exterior use. | |
| EN 13986 | — | The harmonised standard for wood-based panels used in construction. Panels going into a building need CE marking and a declaration of performance under it, covering reaction to fire, formaldehyde class, mechanical properties and biological durability. |
A Class 3 glue line does not make a panel an exterior panel. The bond can survive boiling while the veneers behind it swell, check and delaminate at the edges, because durability of the wood and durability of the adhesive are separate properties. Exterior service needs the use class, the edge sealing and the coating specified together — and an untreated exposed edge is where every plywood failure in a hot, humid climate begins.
Plywood
Four things a plywood order needs beyond the thickness.
Thickness and sheet size are the easy part. What separates two quotations on “18 mm birch” is usually the construction, the face grade, the tolerance and the film.
- Construction — birch or combi
- All-birch panels have birch throughout the core and the faces; combi panels have birch faces with a softwood core, or alternating layers. Combi is lighter and cheaper, and it is not the same panel — screw holding, edge quality, stiffness and impact resistance all differ. An enquiry for “birch plywood” that is answered with combi is not being cheated, it is being answered loosely, so name the construction.
- Face grade
- Face and back are graded separately and quoted as a pair — a B/BB panel has a better face than back. The grade governs patches, plugs, colour and open defects, and it is the largest single price step in the panel.
- Film-faced, for formwork
- Phenolic film on both faces, typically in the 120–220 g/m² range, with the film weight governing the number of pours the panel will give and the finish it leaves on the concrete. Edges sealed at the mill; every cut edge on site has to be resealed by the user or the panel takes water through it. Reuse cycles quoted by a supplier assume the edges are maintained — and on most sites they are not.
- Thickness tolerance and sanding
- Sanded, unsanded or calibrated. Where the panel goes into a machine-fed process or a laminated assembly, the tolerance matters more than the nominal thickness, and it should be a line in the order.
- LNG cargo-containment grade
- Insulation plywood for membrane containment systems is a qualified product within a qualified supply chain. Approval sits with the containment-system licensor and the yard's quality regime, not with a merchant, and we will say plainly what we can and cannot arrange rather than imply an approval we do not hold. Enquiries here are handled as a project, with the approval position established first.
Boards
MDF, OSB and particleboard — the type number is the specification.
Each of these families is defined by a type range in its own standard, and the type sets the load-bearing capability and the humidity the panel can live in. A board ordered without a type number is a board ordered on price alone.
| Panel | Standard | Type range | The distinction that matters |
|---|---|---|---|
| OSB | EN 300 | OSB/1 to OSB/4 | OSB/1 is interior, non-load-bearing. OSB/2 is load-bearing in dry conditions. OSB/3 is load-bearing in humid conditions — the general construction grade. OSB/4 is heavy-duty load-bearing in humid conditions. Substituting OSB/2 for OSB/3 on a humid site is the classic false economy. |
| Particleboard | EN 312 | P1 to P7 | P1 and P2 are interior, non-load-bearing — P2 being the furniture board. P3 is non-load-bearing in humid conditions; P5 is load-bearing in humid conditions; P7 is heavy-duty. Furniture board in a wet application swells irreversibly and does not recover. |
| MDF | EN 622-5 | MDF, MDF.H, MDF.LA and others | Standard, humid-resistant and load-bearing variants. Fire-retardant grades are a separate specification with their own reaction-to-fire classification, and the classification travels with the panel, not with the brochure. |
Emissions
Formaldehyde class, and which market you are shipping into.
Wood-based panels bonded with amino resins emit formaldehyde, and the permitted level is regulated differently in different markets. This is the specification most often left out of an enquiry and most often the reason a shipment is rejected at the destination.
- European classes
- E1 is the general European class, declared under EN 13986 and tested by the chamber method of EN 717-1. Lower-emission products are marketed as E0 or as fractions of the E1 limit — those are producer designations rather than a separate harmonised class, so the number and the test method both have to be stated.
- North American requirements
- CARB Phase 2 and the federal TSCA Title VI rule set their own limits and require third-party certification and labelling. A panel that is compliant in Europe is not automatically compliant for a US or Canadian destination, and the certification cannot be added after production.
- Project specifications
- Green-building schemes frequently specify emission levels tighter than the regulatory minimum. If your project is chasing a rating, the emission class belongs in the enquiry, because it changes the resin system and therefore the producer.
Straight answer
What it is not, said before you find out.
- “Waterproof” is not a class and we will not write it into an offer
- Bonding class to EN 314-2 and use class to EN 636 are the two things that can be specified and tested. Anything else is a description.
- Film-faced reuse figures assume maintenance you will not do
- Cut edges resealed after every cut, panels cleaned rather than scraped, stacked flat and dry. The published cycle count is an upper bound achieved under those conditions, and site reality takes a large bite out of it.
- Birch and combi are not the same panel
- They differ in weight, stiffness, screw holding and edge quality. Name the construction in the enquiry or you are letting the cheapest interpretation win.
- We do not hold LNG containment approvals
- Approval for cargo-containment insulation material sits with the system licensor and the yard. We will tell you what is arrangeable and what is not, and we will not imply a qualification we do not have.
- A décor match across producers does not exist
- Faced board references belong to the producer. Matching an existing installation means going back to the original producer and reference, and where that producer has discontinued the décor there is no equivalent, only a near miss.
- Panels are damaged in handling more often than in service
- Corner and edge damage, moisture pickup through unsealed edges, and distortion from being stacked on an uneven base. Packing and stacking instructions are part of the specification, and we would rather over-specify the packing than argue about the arrival condition.
How to specify
Nine lines, and we can price it properly.
- 1 · Panel family and type
- Plywood, MDF, OSB or particleboard — with the type number where the standard has one: OSB/3, P5, MDF.H.
- 2 · Bonding and use class
- EN 314-2 class and, for plywood, the EN 636 use class.
- 3 · Construction
- For plywood: all-birch or combi, ply count, and face and back grades as a pair.
- 4 · Dimensions and tolerance
- Sheet size, thickness, and the thickness tolerance where the panel feeds a machine or a laminated assembly. Sanded, unsanded or calibrated.
- 5 · Surface
- Raw, film-faced with the film weight, melamine or foil-faced with the décor reference, or veneered.
- 6 · Formaldehyde class
- E1, a lower producer designation, or CARB Phase 2 / TSCA Title VI for a North American destination.
- 7 · Reaction to fire
- Where the panel is going into a building, the required Euroclass — which may mean a fire-retardant grade rather than a coating applied later.
- 8 · Certification
- CE marking and declaration of performance to EN 13986 where the use is structural or in construction; FSC or PEFC where required.
- 9 · Destination, quantity and timing
- Port and country, volume per thickness, and whether this is one parcel or a programme.
Inspection
What we check, and what travels with the goods.
- Type testing and factory production control
- Bonding quality to EN 314-2, panel properties and CE marking with the declaration of performance to EN 13986, formaldehyde emission by the declared test method, and the producer's factory production control certification. Reports supplied with the first order and on any change of production specification.
- Pre-shipment inspection
- Where the buyer requires it, an agency appointed for the consignment — SGS, Bureau Veritas or Intertek — instructed jointly, verifying panel count, sheet dimensions, thickness across the parcel, face grade against the specification, film weight where film-faced, edge sealing, marking, pallet condition and moisture protection.
- Condition on arrival
- Wrapping intact, edges undamaged, no water staining, panels flat and stacked on a level base. Panels absorb moisture through unsealed edges faster than through faces, so edge condition on arrival is the reading that predicts service life.
- Documentation per shipment
- Declaration of performance and CE marking where applicable; bonding class and use class certificates; formaldehyde emission certificate naming the test method, plus CARB or TSCA certification for a North American destination; reaction-to-fire classification report where a fire grade is specified; FSC or PEFC certificate and transfer document where sold certified; packing list with pallet numbers, sheet counts and dimensions; certificate of origin naming the producing mill; bill of lading; and the inspection report where an agency is appointed.
Enquiries
Every enquiry is answered by the desk that handles it.
Send the product, quantity, delivery basis, destination and timing. We revert with availability, an indication and the documentation that accompanies it. Specifications are released once we know who we are speaking with.