GRP or GFK — Is It the Same Material?
If you've compared composite suppliers, you've probably seen both GRP and GFK used for what looks like the same product — sometimes even from the same supplier. Here we explain what the terms actually mean, where they come from, and whether it matters which one you use in an enquiry.
Summary
- GRP and GFK refer, in practice, to the same material: a composite of glass fibre and resin.
- GRP (Glass Reinforced Polymer/Plastic) is the English term and the most widely used internationally.
- GFK (Glasfaserverstärkter Kunststoff) is the German term, which has spread through trade with German industry.
- Glass reinforced plastic is the standard English phrasing used in most European technical standards.
- It normally makes no practical difference which term you use in an enquiry, as long as the product specification, standard and dimensions are stated correctly.
The terms at a glance
| Term | Linguistic origin | Full meaning | Most common in |
|---|---|---|---|
| GRP | English | Glass Reinforced Polymer / Glass Reinforced Plastic | International construction, industrial and infrastructure sectors |
| GFK | German | Glasfaserverstärkter Kunststoff | German- and Central European-influenced industry, some Nordic suppliers |
| FRP | English | Fibre Reinforced Plastic/Polymer | Broader umbrella term that also covers carbon fibre and aramid fibre |
| Glass reinforced plastic | English | Full written-out form of GRP | European standards and formal technical text |
| Composite material | English | Generic term for a material built from multiple constituents | Broad use, less technical precision |
Is it exactly the same material?
Yes, in practice GRP and GFK refer to the same material type: glass fibre embedded in a resin matrix, usually polyester, vinyl ester or epoxy based. The only real difference is which language region the term originates from, not the material's composition or properties. FRP is a broader term that technically also covers reinforcing fibres other than glass, such as carbon and aramid, but in everyday use FRP and GRP are often treated as synonyms when referring to glass fibre products.
Why do different suppliers use different terms?
Which term a supplier uses usually reflects where in Europe their trade relationships and original product development have their roots. British and international manufacturers, such as Dura Composites, consistently use GRP. Suppliers with stronger ties to German or Central European industry often use GFK instead. Both terms appear in the Nordic market, often depending on which market a given supplier has historically sourced from.
Does it matter which term I use in an enquiry?
No, not for the material choice itself. What actually determines whether a product meets a project's requirements is the technical specification: standard (for example EN 13706 for pultruded profiles), dimensions, resin system, fire class and load data. Writing ”GRP grating” or ”GFK grating” in an enquiry normally produces the same result, provided the technical specification is clear. For formal procurement or specification, we still recommend using GRP or the full written form glass reinforced plastic, since that is the terminology most consistent with European standard documentation.
Other terms worth knowing
Pultruded — a manufacturing method in which continuous glass fibre profiles are pulled through a resin bath and forming die, common for profiles and beams.
Moulded — a manufacturing method where the material is formed in a mould, common for grating.
Resin system — the polymer matrix (polyester, vinyl ester, epoxy or phenolic) that binds the glass fibres together and helps determine chemical and fire performance.
d² — Dura Composites' own product range of GRP grating and profiles, distributed in Sweden by Byggkomposit.
Frequently asked questions
Is GFK a worse or better material than GRP?
No. GFK and GRP are the same material type under different names. Quality differences come from the manufacturer, resin system and production process — not from which term is used.
Which term should I use in a technical specification?
We recommend GRP or glass reinforced plastic, as this is the terminology found in European standards such as EN 13706. GFK also works but is less common in formal English-language specifications.
Is FRP the same as GRP?
FRP is a broader term that also covers reinforcing fibres other than glass, such as carbon fibre. For products using glass fibre, FRP and GRP are often used as synonyms.
Why do some suppliers call it ”composite” instead?
Composite is a generic term for a material built from multiple constituents and can refer to far more material types than glass reinforced plastic. It's often used in marketing but is less precise in a technical specification.
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