Two metals, both used outdoors for good reasons. This guide compares a stainless steel outdoor kitchen with marine-grade aluminum by criteria, not by rank, for gardens near salt water and pools.
01 Criteria
Both metals are used in outdoor kitchens across Florida, and both can last near the coast when the details are right. The question is less which metal, and more which grade, which surface and how much care.
Both metals protect themselves with a thin oxide film that forms again after damage: chromium oxide on stainless steel, aluminum oxide on aluminum. Neither metal is immune to every environment.
Four things decide how either metal ages near salt water:
02 Two metals
Stainless steel does well where heat and food meet. Stainless steel is common for grills, ovens, sinks and other food-contact surfaces. It resists major deformation up to about 1,000 °F, cleans with soap and water and does not alter the taste of food. In a FREILUFT kitchen, that is a grill-and-fire element built from stainless steel, cast iron and firebrick, and the sink if you choose stainless steel.
Stainless steel is a family of more than 100 alloys. Two grades are common in architecture: Type 304, and Type 316, which adds 2 to 3 percent molybdenum for better resistance to chlorides.
Within about 3 miles (5 km) of surf, industry guidance calls for Type 316 as a minimum. Lower grades such as Type 304 will probably tea-stain near the sea. Tea staining is a brown discoloration of the surface. It is cosmetic and does not weaken the steel, and it appears mostly where rain does not wash the surface.
Aluminum alloys with magnesium, the 5xxx series, resist corrosion in the marine environment and are widely used in marine applications, including hulls in constant contact with seawater. FREILUFT cabinets stand on the PureAlu Cabinetry System made from 5/16 in (8 mm) marine-grade aluminum. The alloy is marine-grade aluminum AlMg 3.5, an alloy class proven in shipbuilding.
Aluminum weighs about one third as much as stainless steel: about 2.7 g/cm³, against 7.9 to 8.0 g/cm³ for Types 304 and 316. The weight of a finished module also depends on its wall thickness. Under a powder coat, the chemical pretreatment of the aluminum is essential for corrosion resistance. For salt air, the SEASIDE class of the QUALICOAT quality label asks for a deeper etch and a test for filiform corrosion. Ask every supplier which pretreatment and coating class they use.
03 On the coast
Near salt water, the same rules apply to both metals. These are the points that decide how a kitchen looks after years outside.
04 In short
Choose by grade, surface and care, not by the name of the metal.
05 At a glance
No ranking. Each row shows what to look at for either metal and what to ask before you decide. For stone, masonry, HDPE and wood, see outdoor kitchen materials for Florida. Every FREILUFT kitchen is made to order in Germany, and we plan and supply them in South Florida.
| Stainless steel | Marine-grade aluminum, powder-coated | |
|---|---|---|
| Protection | A chromium oxide film; the grade decides how it holds up against chlorides. | An aluminum oxide film under the coating; the pretreatment decides how the coating holds up. |
| Near the coast | Higher grades near surf; tea staining where rain does not reach. | Aluminum-magnesium alloys for marine use; pretreatment classes for salt air. |
| Typical use | Grills, ovens, sinks, food contact | Cabinet bodies and fronts |
| Care | Regular washing near the sea, more often in sheltered spots. | Regular washing near the sea and pools with mild detergent. |
| Ask about | Grade of every part, surface finish, fasteners | Alloy, thickness, pretreatment, coating, isolation from steel parts |
It can be, with the right grade and care. Within about 3 miles (5 km) of surf, industry guidance calls for Type 316 as a minimum. Lower grades such as Type 304 will probably tea-stain near the sea.
Tea staining is a brown discoloration of the surface. It is cosmetic and does not weaken the steel, and it appears mostly where rain does not wash the surface.
Both metals protect themselves with a thin oxide film that forms again after damage: chromium oxide on stainless steel, aluminum oxide on aluminum. Neither metal is immune to every environment. That is why the alloy and the coating matter.
Near the sea, industry guidance suggests washing Type 304 stainless steel 4 to 12 times a year where rain does not reach it and salt builds up, with mild detergent and clean water, never with cleaners containing chlorides or bleach. For powder-coated aluminum, QUALICOAT recommends cleaning every three months near the sea and around pools, with a soft cloth, mild detergent and a fresh-water rinse.
Stainless steel screws in aluminum are common, but separating the metals with plastic or neoprene washers or sleeves prevents galvanic corrosion; paint alone is not a reliable insulator.
Aluminum weighs about one third as much as stainless steel: about 2.7 g/cm³, against 7.9 to 8.0 g/cm³ for Types 304 and 316.
Ask for material samples with your design consultation. Coated aluminum, colors and stone are easier to judge in your own light.
Tell us where your kitchen will stand, by the pool, under the lanai or on the water, and ask for material samples. We reply personally within one business day.
