304 vs 316 stainless mesh: which security screen to buy
This single spec decides whether your screens still look right in five years, and most sales conversations skip past it. Here's the whole story in plain terms.
| Type 304 | Type 316 | |
|---|---|---|
| Composition difference | No molybdenum | Contains molybdenum |
| Chloride (salt) resistance | Poor — pits and stains | Strong |
| Inland performance | Perfectly adequate | Adequate, and you overpaid slightly |
| Coastal performance | Rust staining within a few seasons | Holds up for the life of the frame |
| Relative cost | Lower | Roughly 15–30% more on the mesh |
| Where it makes sense | Phoenix, Tucson, Las Vegas, Dallas, inland Sacramento | San Diego, Miami, Fort Lauderdale, Tampa, Houston's coastal edge |
What salt actually does
The verdict
Inland and dry — Phoenix, Tucson, Las Vegas, most of Dallas — 304 is a sound buy and the premium for 316 is largely wasted on you.
Within a few miles of salt water, 316 is not an upsell, it's the specification. A 304 screen in coastal San Diego or Fort Lauderdale will show tea-staining within a few seasons, and no warranty covers cosmetic corrosion from a known-unsuitable alloy.
How to check a quote: the alloy should be written on the quote, not described verbally as 'marine grade'. That phrase is unregulated. Ask for the number.
Common questions
Is marine grade the same as 316?
'Marine grade' is a marketing phrase with no enforced definition. 316 is a specification. Ask for the number in writing — if a contractor won't put the alloy on the quote, that tells you something about the rest of the job.
How far from the ocean does 316 stop mattering?
There's no bright line, but salt aerosol drops off sharply past roughly five miles, and terrain and prevailing wind change that a lot. If you can smell the ocean from your driveway, specify 316.
Does the frame alloy matter too?
Yes. A 316 mesh clamped into an under-spec aluminum frame with the wrong fasteners still fails at the fasteners. Ask what the frame and the screws are, not just the mesh.
Get both systems quoted by rated installers
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