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Wood, Galvanised or Stainless: Outdoor Gym Durability by Climate

By OutdoorGym.com Editorial Team · Published October 21, 2026

Inland in the Nordic countries, all three materials can last for decades if water can drain. Galvanised steel sits in the mildest corrosion categories there, robinia and treated timber carry published service lives of 20 years or more, and 304 is the usual stainless grade. Road salt changes that: heavy de-icing moves galvanised steel into a harsher category and stainless guidance to the molybdenum grade, 316. In the Alps, the extra load is ultraviolet light and snow, which attack coatings and wood surfaces, not bare metal. At the coast, chlorides decide: within a few kilometres of surf, zinc coatings are rated in decades, and 316 is the minimum stainless grade in the guidance we found.

The case for one metal over the other is in our stainless steel vs galvanised comparison; this article adds the climate numbers and wood as a third option. Every figure comes from a standard, a public institute, an industry association, a published study or a maker’s own pages, checked in October 2026. Where they give no number, we say so. No public study compares the life-cycle cost of the three materials for outdoor gym equipment, so cost guidance here is qualitative.

What each climate does to a material

Nordic: long frost, thaw days and road salt

The Finnish Meteorological Institute defines winter as the period with a mean temperature below 0 °C. It lasts about 100 days in south-western Finland and 200 days in Lapland, and warm airflows can still raise the daily high above 0 °C at times. Each such thaw and refreeze works water into cracks and coating defects. How many cycles a site sees per year is not specified in the public sources we checked.

Snow is not corrosive; what it carries is. Trafikverket states that it has used 200,000 to 230,000 tonnes of salt a year on Swedish state roads in recent years. Salt reaches a gym beside a treated path on boots and in spray, as our article on outdoor gyms in winter explains. Otherwise the Nordic interior is mild for metal: SSAB describes the typical corrosivity category in the Nordic region as C2 for urban and rural areas, and C3 in some marine environments. Heavy de-icing salt is different; WIEGEL’s technical sheet, citing DIN EN ISO 14713-1, lists it under category C4.

Alpine: ultraviolet light, snow reflection and wet-dry cycles

The World Health Organization states that UV levels increase by approximately 10% with every 1,000 m of altitude. Fresh snow almost doubles a person’s UV exposure, and snow can reflect as much as 80% of UV radiation. UV degrades organic coatings, plastics and wood surfaces; it does not affect zinc or stainless steel.

Snow cover is changing with altitude. The WSL Institute for Snow and Avalanche Research SLF reports a statistically significant trend to less snowy winters at most stations below 1,300 m. Above 2,000 m it finds no clear trend in midwinter snow depth, while the number of snow-covered days is falling at most stations at every altitude. Less snow at lower sites suggests more rain and more wet-dry cycling there. Freeze-thaw counts and humidity figures for alpine sites are not specified in the public sources we checked.

Coastal: chloride aerosol and distance from the surf

Sea spray deposits chloride on every surface it reaches. The Australian Stainless Steel Development Association (ASSDA) states that tea staining on stainless steel occurs most commonly within about five kilometres of the surf. The International Molybdenum Association (IMOA) states that the highest coastal corrosion rates are generally within 400 to 600 m of the shoreline, and lower by a sheltered harbour.

Galvanising guidance uses the same logic. The Galvanizers Association of Australia, applying AS/NZS 2312.2, maps distance from breaking surf to ISO 9223 category: within 50 m is extreme (CX), 50 to 500 m is C5, 500 m to 1 km is C4, 1 to 10 km is C3, and 50 km or more inland is C2. These distance bands are industry guidance, not part of ISO 9223, which sets categories by measured corrosion rate.

Wood

In the maker statements we found, outdoor gym timber is mostly robinia (black locust) or larch. EN 350 groups natural durability against wood-destroying fungi into five classes, with class 1 the most durable. The classes apply to mature heartwood; sapwood of any species counts as not durable (proHolz Austria, citing EN 350-2). On that source’s species cards, European larch and Scots pine are class 3-4, oak class 2 and spruce class 4. Robinia heartwood is class 1-2 under DIN EN 350:2016-12 (Bavarian State Institute of Forestry). One caveat: Richter Spielgeräte, citing Dreiner 2007, states that robinia’s juvenile heartwood, the first 7 to 15 annual rings, is only class 4.

That is why EN 16630 treats ground contact separately. Clause 4.2.3 requires timber components to be designed so that precipitation drains or drips off freely. In ground contact, one or more of three methods shall be used: a species in classes 1 and 2 of EN 350-2; construction methods such as a post shoe; or preservative treatment to EN 351-1 for use class 4 of EN 335-2. Load-bearing timber in constant ground contact that is not a class 1-2 species shall be treated. Clause 4.3.3 adds that wooden equipment shall be made of wood with a low susceptibility to splintering.

Service-life figures come from makers, not from an independent standard. Richter, which uses alpine larch and robinia from Hungary, cites research (Molnar 1988) giving robinia posts 15 to 30 years in ground contact and 60 to 80 years without it. Kompan states that untreated robinia heartwood in soil can last 20 years or more according to DS/EN 350-2. For larch, no maker in our sources publishes a life in years, only guarantees of 2 to 5 years against rot. Figures for treated and thermally modified timber are in the table below.

Climate acts on wood through moisture and UV rather than chlorides. Richter states that drying cracks and splinters occur in every species, cannot be prevented, and are removed at maintenance. A 2024 laboratory study by Asare and colleagues found that 60 full freeze-thaw cycles degraded the mechanical qualities of all nine species tested. Data from installed equipment is not specified in the public sources we checked. In the Alps, UV reaches wood directly: Lunawood reports greying within 3 to 6 months and recommends a UV coating. At the coast, salt does not rot wood but attacks its metal parts, which is why makers specify stainless or plated fixings.

Galvanised steel

Hot-dip galvanising protects carbon steel with a zinc layer that corrodes in place of the steel. Life is a question of zinc thickness and the rate at which the atmosphere consumes it. Thickness is set by EN ISO 1461 and depends on the steel: over 6 mm gets a minimum mean coating of 85 µm, 3 to 6 mm gets 70 µm, 1.5 to 3 mm gets 55 µm and thinner steel 45 µm (Galvanizers Association, UK).

Consumption follows the ISO 9223 category. For zinc, the American Galvanizers Association gives first-year rates of 0.1 to 0.7 µm a year in C2, 0.7 to 2.1 in C3, 2.1 to 4.2 in C4 and 4.2 to 8.4 in C5. Thickness and rate together give the time to first maintenance, which the same association defines as 5% of the base steel surface rusting. For 85 µm, the Galvanizers Association of Australia gives more than 100 years in C2, 40 to more than 100 in C3, 20 to 40 in C4, 10 to 20 in C5 and 3 to 10 in CX. WIEGEL’s table based on DIN EN ISO 14713-1 agrees, with 20 to 40 years in C4 and 10 to 20 in C5; at 55 µm it gives 13 to 26 and 6 to 13.

A Nordic inland site in C2 is the best case, with more than 100 years to first maintenance. Heavy de-icing salt moves the site to C4, where 85 µm is rated at 20 to 40 years and a thin-walled 55 µm frame at 13 to 26. The American Galvanizers Association, writing about salt storage, notes that road salts are aggressive to galvanised steel when wetted and that galvanised steel performs very well with dry salts. For the Alps our sources publish no separate category. Zinc ignores UV, but a powder topcoat does not. EN 16630 clause 4.2.5, on rubbers and synthetics, asks for UV weathering of structural components to be considered. At the coast, 85 µm a few hundred metres from surf falls in the 10 to 20 year band, and within 50 m of surf in the 3 to 10 year band.

Many gym frames are duplex: galvanised, then powder coated. The Galvanizers Association (UK) states that a damaged organic layer needs no urgent repair, because the zinc beneath prevents red rust. The American association puts duplex life at 1.5 to 2.3 times the combined lifetimes of the two systems. Once salt and freeze-thaw have consumed the zinc at a chip, the steel is bare.

Stainless steel: 304 or 316

Stainless steel resists corrosion through its alloy, not a layer. In the EN 10088 ranges tabulated by Euro Inox, 1.4301 (304) has 17.5 to 19.5% chromium and 8.0 to 10.5% nickel; 1.4401 and 1.4404 (316 and 316L) have 16.5 to 18.5% chromium, 10.0 to 13.0% nickel and 2.0 to 2.5% molybdenum. According to the Atlas Steels datasheets, the molybdenum gives 316 higher resistance to pitting and crevice corrosion in chlorides. The same sheets describe 304 as subject to pitting in warm chloride environments, and 316 as not fully resistant to sea water, with brown staining in many marine environments. Stainless does not rust like carbon steel, but it is not immune to chlorides; see our guide to stainless steel outdoor gym equipment.

The failure mode near salt is tea staining. Euro Inox describes it as the initiation of corrosion: sea spray or de-icing salt splashes leave deposits, and tiny pits form under them with a brownish halo. ASSDA calls it cosmetic, with no effect on structural integrity or lifetime.

Grade follows chloride load. Euro Inox states that 1.4301 is the most frequently used grade for interior and mildly corrosive exterior sites: rural, urban and light industrial. For coastal locations, industrial atmospheres and sites exposed to de-icing salts it recommends 1.4401 or 1.4404. ASSDA states that 316 should be selected as a minimum within five kilometres of the surf. Outdoor pools are a middle case: rain washes chlorides away, so Euro Inox accepts 1.4301 there and notes that 1.4404 is commonly used. It adds that a coating cannot justify a lower grade.

The Nordic question is salt and temperature. Houska (2015) reports that sodium chloride becomes continuously corrosive above 10 °C and 76% relative humidity, whereas calcium and magnesium chlorides are corrosive at 0 °C and 45 or 50% respectively. In dry frost, sodium chloride is therefore less active than during a thaw, while the other two act at freezing point. Houska concludes that de-icing salt causes at least superficial staining of 304, and that with a smooth finish 316 is preferred for low to moderate salt exposure. Cold itself is not a problem: the austenitic structure of 316 keeps its toughness down to cryogenic temperatures (Atlas Steels). Where mountain roads are salted, the same de-icing guidance applies.

Maintenance is washing. ASSDA advises a light, regular wash, says rain may be sufficient, and rules out abrasive cleaners and those containing chlorides or bleach. On a waterfront, the whole-of-life study published by ASSDA requires regular wash-downs.

At a glance

Material Nordic inland Alpine Coastal (within a few km of the sea) Maintenance Published service-life statements
Robinia heartwood, untreated (class 1-2) 10-year rot guarantee (one Swedish maker); juvenile heartwood is class 4 n/d; one Bavarian maker uses it for posts in the ground n/d; stainless or plated fixings specified Oil once a year; cracks and splinters removed 15-30 years in ground, 60-80 above (Richter, citing Molnar 1988); 20 years or more in soil (Kompan)
Larch (class 3-4) 5-year guarantee oiled, 2-year unoiled (one maker) Alpine larch from 800-1,800 m (one maker) n/d Linseed oil; oil once a year n/d in years
Pressure-treated timber, NTR class A (ground contact) 20-30 years or more; 20-year rot guarantee (EPD, Bitus AB) n/d n/d n/d 20-30 years or more (EPD)
Thermally modified timber (class 2, use class 3) Not for ground contact Greys in 3-6 months; UV coating recommended n/d; stainless screws recommended UV coating 30 years for cladding and decking (BRE label), not equipment
Hot-dip galvanised steel, 85 µm (steel over 6 mm) C2: more than 100 years; heavy road salt (C4): 20-40 n/d; powder topcoat subject to UV C3: 40 to more than 100; C4: 20-40; C5: 10-20; within 50 m of surf: 3-10 None until 5% red rust; damaged duplex topcoat not urgent 34-174 years on the UK and Ireland map (Galvanizers Association, UK)
Stainless 304 / 1.4301 Rural and urban sites; de-icing salt stains it n/d; toughness retained in cold Not recommended within about 5 km of surf Light regular wash; no chlorides or bleach Indefinite if the surface is maintained (ASSDA, an industry body); one maker publishes a 10-year warranty and 21-year lifecycle without stating the grade
Stainless 316 / 1.4401 / 1.4404 Recommended where de-icing salts are used n/d; toughness to cryogenic temperatures Minimum within 5 km of surf; brown staining still possible As 304; regular wash-downs on a waterfront As 304

“n/d” means not specified in the public sources we checked. Service-life figures are the makers’ or associations’ own statements, not independent tests.

What makers publish

The statements below are what each maker publishes on its own pages or data sheets, checked in October 2026. Makers are listed alphabetically; this is not a ranking. Of the makers listed, Ive Outdoor states that its standard range is made in 304 stainless steel and that it builds gyms in 316 marine-grade stainless steel on request. Its product pages describe the equipment as 100% stainless steel with no paint and no coatings, and cite EN 16630:2015-06E.

Maker Country Material Published durability statement Service life or warranty published
eibe Germany Robinia Usable outdoors without impregnation; resistance only in the heartwood; oil against solar radiation n/d
HAGS Sweden Robinia Naturally rot proof, no chemical protection; stainless or plated steel fixings; galvanised supports n/d
Ive Outdoor Poland Stainless steel 100% stainless steel, no paint, no coatings; EN 16630:2015-06E 10-year commercial warranty; 21-year guaranteed lifecycle
Kompan Denmark Robinia No biocides needed; close to maintenance-free 20 years or more for untreated heartwood in soil, per DS/EN 350-2
Richter Spielgeräte Germany Alpine larch, robinia Larch moderately rot-resistant; robinia posts in the ground without steel feet; cracks and splinters natural Robinia posts 15-30 years in ground, 60-80 years above (citing Molnar 1988)
Svenska Naturlekplatser Sweden Robinia and stainless steel; larch Oil once a year; moving parts checked daily; SS-EN 16630 10 years on robinia, 5 years on oiled larch, 2 years on unoiled larch, against rot
Tress Denmark Larch Linseed oil; minimal maintenance; produced to EN 16630 n/d

How to choose for your site

  • Measure the distance to the sea. Within about 5 km of surf, specify 316 stainless. For zinc, 1 to 10 km from surf is rated at 40 to more than 100 years, 50 to 500 m at 10 to 20, and the last 50 m at 3 to 10.
  • Ask who salts the paths, and with what. Heavy de-icing is category C4 for zinc and a molybdenum-grade case for stainless. Calcium and magnesium chlorides act at 0 °C; sodium chloride needs a thaw.
  • Check the altitude. UV rises by about 10% per 1,000 m and snow reflects up to 80% of it. Budget for UV coatings on wood and expect powder coatings to weather sooner; bare zinc and stainless are unaffected.
  • Keep timber out of the ground unless it qualifies. Under EN 16630 clause 4.2.3 that means a class 1-2 species, a post shoe or use class 4 treatment, plus detailing that drains. Juvenile robinia and sapwood do not qualify.
  • Set the budget horizon first. A 55 µm coating in C4 is rated at 13 to 26 years; 85 µm in C2 at more than 100. Wood costs an oiling cycle; stainless near salt costs washing. Exposure decides which is cheaper, as Gardner and colleagues showed in 2007 for a building against a bridge; put the figures into your outdoor gym cost model.
  • Write the inspection regime into the contract. EN 16630 clause 9.4.1 asks the manufacturer for an inspection frequency that reflects the design, materials and age of the equipment: routine visual checks, an operational inspection every one to three months or as the maker indicates, and an annual main inspection. Clause 4.2.1 requires materials to keep the equipment stable until the next relevant inspection; see our outdoor gym maintenance guide.

Sources

Maker statements come from each maker’s own pages or data sheets, checked in October 2026:

Standards, institutes and associations:

Frequently asked questions

Can wooden outdoor gym posts be set directly in the ground under EN 16630?

Only under conditions. Clause 4.2.3 of EN 16630 requires timber in ground contact to use one or more of three methods: a species in natural durability classes 1 or 2 of EN 350-2, such as robinia heartwood; a construction method such as a post shoe; or preservative treatment to EN 351-1 for use class 4 of EN 335-2. Load-bearing timber in constant ground contact that is not a class 1-2 species shall be treated. Larch, pine and spruce are class 3-4 or 4, so they go into the ground only treated or on a post shoe.

How long does galvanised steel last where de-icing salt is used?

Shorter than the headline figures. A German technical sheet citing DIN EN ISO 14713-1 places heavy de-icing salt loads in corrosivity category C4. For an 85 µm hot-dip coating, which EN ISO 1461 requires on steel over 6 mm thick, two tables give a time to first maintenance of 20 to 40 years in C4. For a 55 µm coating on thin-walled tube the German table gives 13 to 26 years. In a mild Nordic inland atmosphere (C2), the same coating is rated at more than 100 years. The American Galvanizers Association notes, in guidance on salt storage, that road salts are aggressive to galvanised steel when wetted and harmless while dry.

Should I specify 304 or 316 stainless steel for a coastal outdoor gym?

316 (1.4401 or 1.4404). Euro Inox recommends the molybdenum-bearing grades for coastal locations and sites exposed to de-icing salts, and describes 304 (1.4301) as the usual grade for rural, urban and light industrial sites. The Australian Stainless Steel Development Association states that 316 should be selected as a minimum within about five kilometres of the surf. The International Molybdenum Association places the highest corrosion rates within 400 to 600 m of the shoreline. Ask the maker which grade applies to the whole piece, fasteners included, and confirm it in the tender.

Does stainless steel rust outdoors?

Not the way carbon steel does, but it is not immune. Under deposits of sea spray or de-icing salt, tiny corrosion pits can form, surrounded by a brownish halo known as tea staining. Euro Inox describes this as the initiation of corrosion; the Australian stainless association calls it cosmetic rather than structural. Grade 304 is subject to pitting in warm chloride environments, and even 316 is not fully resistant to sea water. Choosing the grade for the chloride load, a smooth finish and regular washing are what keep an outdoor gym free of staining.

How often must outdoor gym equipment be inspected?

EN 16630 clause 9.4.1 requires the manufacturer to provide an orientation on inspection frequency, taking into account the design, the materials used and the age of the equipment. It describes three levels: a routine visual inspection for obvious hazards such as weather damage or vandalism; an operational inspection, which should be carried out every one to three months or as the manufacturer indicates; and an annual main inspection of operational safety, which may require excavation or dismantling of parts. Wooden, galvanised and stainless equipment all fall under the same regime; what differs is what the inspector looks for.

Which material is cheapest over the life of an outdoor gym?

No public study compares the life-cycle cost of wood, galvanised and stainless outdoor gym equipment side by side, so any answer is qualitative. What the sources do show is that exposure decides. A 2007 whole-life study by Gardner and colleagues found carbon steel the most competitive option for an office building and the most expensive for a bridge. For a gym, the cost drivers are the oiling cycle for wood, the time to first maintenance for a zinc coating in the site's corrosivity category, and washing for stainless steel near salt. Model your own site's horizon rather than relying on a generic ranking.

Related reading

Stainless Steel Outdoor Gym Equipment

Why stainless steel is the premium material for outdoor gym equipment: corrosion resistance, 304 vs 316, lifespan and whole-life cost near pools and coast.