Care & Maintenance
Stainless steel is extremely durable and maintenance is simple and inexpensive, but proper care matters, particularly in corrosive coastal conditions. Below is our guide to keeping your stainless steel looking and performing its best, along with the technical background on why coastal discolouration happens and how to prevent it.
Material Description
Stainless steel is extremely durable and its upkeep is simple and inexpensive. Always start with the simplest cleaning solution and only move to something stronger if you need to. Every four to six weeks, wash the surface with a solution of warm water and soap, detergent, or ammonia. Apply the solution with a soft cloth or sponge to avoid damaging the finish, and follow the direction of the polish lines. We recommend a non-scratch cream cleanser for everyday use.
Fingerprints & Smears
Use a quality stainless steel cleaner and polish, applied in accordance with the manufacturer's instructions. Most of these products leave a protective coating that helps prevent future smears and fingerprints from showing.
Grease & Oil
Use a quality commercial detergent or caustic cleaner, applied in accordance with the manufacturer's instructions and always in the direction of the polish lines to avoid scratching the surface.
Precautions
Stainless steel is highly resistant to rust, but it is not impervious to it. Keep it clean and free from contaminants with frequent washing using mild soap and water or glass cleaner and a cotton cloth. Avoid prolonged contact with chlorides, bromides, thiocyanates and iodides, particularly where acidic conditions exist, and never let salty water evaporate and dry on the surface. The following common causes of corrosion and discolouration should always be avoided.
Coastal Environments
Tea staining is a brown discolouration that can appear on the surface of stainless steel due to corrosion in coastal environments. It is a cosmetic issue only and does not affect the structural integrity or lifespan of the material, but it can spoil the look of an otherwise sound installation if it is not managed.
It occurs most commonly within around five kilometres of the surf and becomes progressively more likely the closer an installation is to the marine source. Wind exposure, pollution, local shelter and higher temperatures can all extend the risk well beyond the immediate coastline, and sheltered bays or areas that do not get washed by rain are particularly susceptible.
Tea staining should not be confused with other causes of surface staining, such as carbon steel contamination, uncleaned welds, or exposure to chemical fumes like hydrochloric acid or bleach.
The factors behind tea staining are complex, but they generally come down to local conditions, such as temperature, humidity and the presence of corrosive elements on the surface, being too aggressive for the grade of stainless steel used and its installed condition.
The good news is that tea staining is well understood and highly preventable with the right grade of material, the right surface finish, and a sensible maintenance routine. Marine environments are among the most demanding for any building material, but a well specified stainless steel installation can remain structurally sound and presentable for decades.
Prevention
Preventing tea staining starts long before installation. These are the key principles we apply to every marine and coastal project.
The Right Grade
In marine environments we specify grade 316 stainless steel, or an equivalent with matching corrosion resistance, as standard. It is the industry benchmark for saltwater exposure.
A Smooth, Clean Finish
The smoother the surface, the lower the risk of tea staining. A fine mechanically finished or mirror polished surface sheds salt and contaminants far more easily than a rough one.
Weld Treatment
Welds are pickled and passivated after fabrication to remove welding oxide and the chromium depleted layer beneath it, restoring the material's natural corrosion resistance.
Ongoing Maintenance
Regular washing removes the salt and other deposits that lead to tea staining, and rain washing helps too, provided the installation is designed to drain well. As a guide, if a nearby window needs washing, your stainless steel probably does too. The table below is a general guide to recommended cleaning frequency, based on ASSDA technical guidance for 304 grade stainless steel in Australian conditions. Areas exposed to seaside, industrial or severe conditions need more frequent attention than sheltered inland settings.
| Setting | Rain Washed, No Deposits | Rain Washed, Deposits Accumulate | Sheltered, No Deposits | Sheltered, Deposits Accumulate |
|---|---|---|---|---|
| Rural, suburban & residential | Once a year | Once a year | 1–2 times a year | 2–12 times a year |
| Seaside, industrial & severe | Once a year | Once a year | 3–4 times a year | 4–12 times a year |
Guidance adapted from ASSDA Technical FAQ No. 6, Preventing Coastal Corrosion (Tea Staining). Cleaning frequency can vary depending on the specific alloy and surface finish used, and washing should always be done with clean water and a mild, non-chloride detergent.
If you are unsure about the right cleaning routine for your stainless steel, or you are starting to see discolouration, get in touch and we will point you in the right direction.
