Short answer
304 is enough for most inland gardens and is what the standard range is made from. 316 is worth the extra where the site is close enough to salt water for spray to reach the panels, or where the cabinets sit in persistent damp shade. The material cost of 316 is roughly twice 304.
What the difference actually is
316 adds molybdenum to the alloy. That addition is what improves resistance to chlorides — salt — which is the specific thing that attacks stainless near the coast.
It is not a general upgrade to a better metal. Away from chlorides, 304 performs essentially the same, and paying for 316 there buys nothing you will notice.
When 316 is worth it
Within a few kilometres of open sea, where salt spray lands on surfaces and then dries, concentrating the chloride. A pool, if the cabinets are close to it and splash reaches them — pool water is a chloride source too.
Persistent damp shade, where a surface never fully dries. Corrosion needs an electrolyte, and a surface that stays wet has one.
When 304 is the right answer
Inland gardens, covered terraces, courtyards. The overwhelming majority of what we ship is 304 and performs for the life of the kitchen.
A roof over the run is worth more than the alloy upgrade. Keeping rain and spray off a surface does more for corrosion resistance than moving from 304 to 316 does on an exposed site.
What actually causes failure
Not the rain. Rain washes a surface and runs off. The failure modes are standing water in a joint or a packed gap, chloride from salt or pool water drying on the surface, and contact with a dissimilar metal or with a carbon steel tool that leaves iron particles to rust.
So the practical measures are drainage, a roof, and rinsing occasionally on a coastal site. Alloy choice is the third line of defence, not the first.
The comparison, in one table
| 304 | 316 | |
|---|---|---|
| Where it is enough | Inland gardens, sheltered courtyards, most suburban sites | Coastal sites with salt in the air, poolside, marine exposure |
| Relative material cost | Baseline | Roughly double the 304 material cost |
| What attacks it | Chlorides in standing water, and mild steel fixings nearby | Very little in a domestic setting |
| What it does not fix | Water sitting against the steel, whatever the grade | Water sitting against the steel, whatever the grade |
| Standard in the range | Yes — the default | Optional upgrade, quoted per order |
Questions we get about this
Do I need 316 for a coastal garden?
Where salt spray reaches the cabinets, it is worth the cost, and we will say so before you order. Where the run is under a roof and set back from the sea, 304 is usually enough and we will say that too.
How much more does 316 cost?
The material cost is roughly twice that of 304. The share of that in the finished cabinet is smaller, but it is a real increase and not a marginal one.
Does 316 stain less?
It resists chloride pitting better. It still develops tea staining in coastal air if it is never rinsed, so the maintenance advice is the same either way.
Before you order anything
Send the grill model and the run length. You get the aperture, the module list and one itemised price back in writing — freight shown separately, valid 15 days.