Comparison
PVB vs EVA vs SGP: which interlayer should you specify?
PVB is the general-purpose structural interlayer requiring an autoclave. EVA cures without an autoclave and tolerates moisture better, suiting decorative and encapsulated work. SGP (ionoplast) is roughly five times stiffer than PVB and is specified where structural performance governs — at a considerably higher cost.
ImageThree laminated glass samples side by side, each showing a different interlayer at the polished edge
The three interlayers in common use solve the same problem in different ways, and the right choice is almost always determined by two questions: what structural performance does the panel need, and what lamination equipment do you actually have?
PVB, EVA and SGP compared
Values are indicative for typical commercial grades and vary by manufacturer and grade.
| Property | PVB | EVA | SGP (ionoplast) |
|---|---|---|---|
| Processing | Autoclave required | Vacuum bag or laminator, no autoclave | Autoclave required |
| Relative stiffness | Baseline | Lower than PVB | ~5× PVB |
| Structural performance | Good | Moderate | Highest — allows thinner glass build-ups |
| Moisture tolerance | Low — hygroscopic, needs controlled storage | High — suits exposed edges | High |
| Edge stability | Requires edge protection when exposed | Good exposed | Excellent exposed |
| Clarity over time | Excellent | Good; lower grades can yellow | Excellent |
| Acoustic performance | Good; acoustic grades available | Moderate | Lower than PVB — stiffness reduces damping |
| Relative cost | Low | Low to moderate | High |
| Best suited to | General architectural and automotive glazing | Decorative, encapsulated inserts, humid exposure | Structural glazing, large spans, point-fixed panels |
When PVB is the right answer
For the large majority of architectural and automotive laminated glass, PVB is the correct specification. It has the widest supply base, the lowest cost, the best acoustic behaviour of the three, and a performance envelope that comfortably covers facades, balustrades, overhead glazing and windscreens.
Its two real constraints are equipment and storage. It needs an autoclave, and it needs controlled-humidity storage because it is hygroscopic. Processors with both find no reason to move away from it for standard work.
When EVA earns its place
EVA is chosen for two reasons: no autoclave, and moisture tolerance. A processor without autoclave capacity can produce laminated glass with a vacuum bag and an oven, which changes the economics for smaller operations and for decorative work.
It also bonds to a wider range of inserts — fabrics, meshes, LEDs, veneers — because the lower processing pressure does not crush them. And because it tolerates moisture, it suits panels with permanently exposed edges where PVB would delaminate over time.
The trade-off is structural: EVA is softer, so a given build-up carries less load and deflects more than the PVB equivalent.
When SGP is worth the cost
SGP is an ionoplast interlayer roughly five times stiffer than PVB and with substantially higher tear strength. That stiffness means the two glass plies act closer to a single composite section rather than two sheets sliding over an interlayer.
The practical consequence is thinner glass for the same load, or longer spans and fewer fixings for the same thickness. On large structural panels, point-fixed glazing, glass fins and long-span balustrades, that can offset the higher interlayer cost against reduced glass weight and simpler support structure.
For standard glazing it rarely pays. And note that its stiffness reduces acoustic damping — on a noise-driven facade, PVB outperforms it.
Choosing in practice
- Standard architectural or automotive glazing, autoclave available → PVB.
- No autoclave, or decorative inserts, or permanently exposed edges → EVA.
- Structural glazing, long spans, point fixings, or minimum glass thickness → SGP.
- Acoustic performance is the governing requirement → PVB, in an acoustic grade.
- Coloured or printed effect inside a safety laminate → PVB, in a coloured or printed grade.
Frequently asked questions
Can PVB and SGP be combined in one laminate?
Yes, hybrid build-ups exist, but they need care. The two interlayers have different stiffness and thermal behaviour, so the laminate must be designed for the combination rather than treated as a simple stack. Consult the structural engineer on any hybrid specification.
Is EVA cheaper than PVB?
Per square metre the materials are broadly comparable, and PVB is often cheaper. The saving with EVA is capital: it does not require an autoclave, which is a significant investment. For a processor that already has one, PVB is usually the lower total cost.
Which interlayer is best for hot and humid climates?
For exposed-edge applications in humid conditions, EVA and SGP both outperform PVB. Where the laminate is properly framed with protected edges — which is most architectural glazing — PVB performs well and remains the standard specification across the Middle East and South Asia.