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What makes EPDM seals ideal for outdoor use. Tips on selection, care, applications and service life.
Whether in housebuilding, in industry or in technical systems – seals are inconspicuous but indispensable. They provide protection against moisture, reliably seal components and prevent damage from weather or temperature fluctuations.
Particularly outdoors, seals must withstand extreme conditions: sun, rain, frost, ozone and UV radiation act on them permanently. One of the best solutions is the EPDM seal. It is considered particularly robust and durable.
But which seal is the right one? This article explains in detail what matters when making a selection, which variants exist and why EPDM is usually superior to other materials.
Properties of EPDM seals
EPDM stands for ethylene propylene diene rubber and is one of the synthetic elastomers. The material was specifically developed to withstand the highest loads outdoors.
EPDM is characterised by an extraordinarily high resistance to UV rays and ozone. While other rubbers quickly become brittle through solar radiation, EPDM remains elastic over many years. Even extreme temperatures can do little to harm the material. In a range from –40 °C to +120 °C it remains dimensionally stable and flexible.
Special variants even withstand up to +150 °C. In addition, EPDM is resistant to water, steam as well as diluted acids and alkalis. This combination of weather resistance, elasticity and chemical resistance makes EPDM a universal material for outdoor use.
Requirements outdoors
Seals that are used outdoors must withstand very special challenges. Strong solar radiation can dry out materials, ozone and UV radiation cause many rubbers to age and become cracked.
Added to this are extreme temperature fluctuations that stress the material: while frost prevails in winter, the surface can heat up strongly in summer. Mechanical effects such as pressure, movement or vibration also act permanently on seals. EPDM seals are specially designed to reliably master these stresses.
They remain dimensionally stable and elastic even under long-term load and retain their sealing function even after many years in use. This clearly distinguishes them from natural rubber or NBR, which age much faster under the same conditions.
Selection criteria for the right EPDM seal
The right choice of an EPDM seal depends on several factors. A decisive aspect is the hardness (Shore A), which describes the softness or hardness of the material. Here are some important points:
- Soft EPDM seals (low Shore A value): They adapt particularly well to uneven surfaces and thus ensure reliable sealing even with slight deformation or irregular surfaces.
- Medium hardnesses: These offer a good compromise between flexibility and load capacity and are suitable for many standard applications in construction and industry.
- Hard EPDM seals (high Shore A value): They are particularly resistant to mechanical loads, vibrations or pressure and are therefore often used in industrial systems or vehicles.
Besides the hardness, the profile shape also plays an important role. Depending on the application, hollow chamber profiles, solid profiles, lip seals, round cords or strips may be the suitable solution. Dimensional accuracy is equally important, because only precisely fitting seals can reliably fulfil their function.
For special requirements there are also special designs, for example with adhesive layer, reinforcements or complex geometry. This allows EPDM seals to be optimally adapted to the respective application environment.
Typical areas of use outdoors
Window and door seals
EPDM seals ensure reliable sealing against draughts, noise and moisture on windows and doors. They prevent heat from escaping and thus contribute considerably to energy savings.
At the same time they protect against penetrating rainwater and prevent damage to building structures. Thanks to their high flexibility they easily compensate for even slight deformation or movement of the building elements.
Roof and façade seals
In the area of flat roofs, conservatories or façades, the weather resistance of EPDM plays out its full strength. The seals reliably protect against penetrating water for many years and withstand both strong solar radiation and frost.
Even in combination with insulation materials or other sealing systems, EPDM remains permanently elastic and stable, which considerably increases the safety and durability of buildings.
Automotive and vehicle construction
In the automotive sector, EPDM seals are used on doors, windows, boot lids and sunroofs. They must absorb vibrations, compensate for movements and at the same time ensure an airtight and watertight closure.
In addition they contribute to noise insulation and increase driving comfort. The long durability of EPDM is particularly important here, as vehicles must offer the same protection over many years.
Garden and landscape construction
In garden and landscape construction, EPDM products are used among other things for pond liners, hoses or covers. The material remains elastic and tear-resistant even under permanent exposure to water and moisture.
EPDM pond liners, for example, are extremely resistant and can fulfil their function for decades. EPDM is therefore suitable for applications where permanent watertightness is indispensable.
Machine and plant construction
Outdoor machines, pumps or technical housings must be protected against moisture, dust and other environmental influences. EPDM seals ensure that sensitive components are reliably sealed.
Thanks to their high resistance to ozone, UV rays and temperature changes, they are particularly suitable for devices and systems that are permanently outdoors and exposed to strong loads.
Comparison with other materials
In comparison with other sealing materials, it becomes clear why EPDM is often the first choice for outdoor use. NBR, i.e. nitrile rubber, does have a high resistance to oils and fuels, but is hardly UV- and ozone-resistant.
NBR is therefore only suitable to a limited extent for outdoor use. Silicone, on the other hand, scores with excellent temperature resistance and remains flexible even at very high temperatures. However, it is considerably more expensive and mechanically less resilient. Natural rubber, in turn, is cost-effective and sufficient for simple applications, but outdoors it very quickly loses its elasticity and becomes cracked.
EPDM, by contrast, combines high resistance to weather, good mechanical load capacity and an attractive price-performance ratio. It is therefore regarded as the all-rounder among sealing materials for outdoor use.
Comparison table of materials
| Material | Advantages | Disadvantages | Suitable for |
|---|---|---|---|
| EPDM | Very resistant to UV, ozone and weather, flexible at –40 °C to +120 °C, durable | Less suitable for contact with oils and hydrocarbons | Construction, vehicle construction, outdoor seals |
| NBR | High resistance to oils and fuels | Hardly any UV and ozone resistance | Hydraulics, mechanical engineering indoors |
| Silicone | Extreme temperature resistance up to +200 °C, elastic | More expensive, less mechanically resilient | High-temperature applications |
| Natural rubber | Inexpensive, good elasticity | Ages quickly outdoors, low weather resistance | Simple seals indoors |
Care & service life
EPDM seals are easy to maintain. Nevertheless, it is worth observing a few points in order to further increase their service life:
- Regular cleaning with mild soap solutions prevents deposits of dirt and moss.
- Aggressive chemicals or solvents should be avoided, as they can attack the surface.
- For mechanically stressed seals, occasional checking for cracks or material fatigue is advisable.
Under normal conditions, EPDM seals can easily last 20 to 25 years – a considerably longer period than with many alternative materials.
Costs & economic efficiency
EPDM seals are somewhat more expensive to purchase than simple standard rubber seals, but in the long term they are the clearly more economical solution. While cheaper materials often become brittle after just a few years and have to be replaced, EPDM seals remain functional over decades.
This reduces not only the material and labour costs for replacement, but also the downtime of systems or buildings that depend on an intact seal. Particularly in the industrial sector, where repairs quickly cause high costs, EPDM seals therefore pay for themselves within a short time.
In private construction too, they provide long-term safety and prevent consequential damage that can arise from penetrating moisture. The investment in EPDM therefore pays off several times over: it saves time, money and secures the functionality of your buildings or systems.
Example calculation of cost-benefit
| Material | Average service life | Replacement cycles in 20 years | Total costs (material & replacement) |
|---|---|---|---|
| EPDM | 20–25 years | 1 | Medium, but cheaper in the long term |
| NBR | 5–7 years | 3–4 | Higher due to frequent replacement |
| Natural rubber | 3–5 years | 4–6 | Very high, as more frequent replacement is necessary |
Sustainability of EPDM seals
A further advantage of EPDM lies in its sustainability. Since the material functions reliably over decades, considerably fewer replacement cycles are necessary. This saves resources, reduces waste and ensures a better environmental balance.
In contrast to many cheaper rubber materials, which frequently have to be disposed of and replaced, EPDM represents a long-lasting solution. In addition, manufacturers are increasingly working on making EPDM recyclable and returning production residues to the material cycle.
EPDM also contributes to environmental protection in its use itself: window and door seals made of EPDM help to minimise energy losses and thereby reduce the heating and cooling requirements of buildings. The use of EPDM seals thus contributes not only to extending the service life of buildings, but also to achieving climate protection targets.
What you should look out for when selecting
The choice of the right seal for outdoor use decides the service life and functional reliability of many buildings, vehicles and systems. EPDM offers decisive advantages here through its high weather resistance, flexibility and chemical resistance compared with other materials.
When selecting, make sure that the seal is exactly matched to your application – with regard to hardness, profile shape and dimensional accuracy. Only in this way can it reliably fulfil its function over years. The somewhat higher purchase costs are quickly offset by the long service life and low maintenance expenditure.
In addition, EPDM is not only a technically but also an ecologically sensible choice, as it saves resources and supports energy efficiency. Anyone wishing to plan for the long term can hardly avoid EPDM – it is the right solution for all who want to combine safety, economic efficiency and sustainability outdoors.
Frequently asked questions
Is EPDM suitable for permanent UV exposure? Yes, EPDM is designed for continuous outdoor use and remains elastic even under intensive solar radiation.
Which temperature ranges are possible? Standard EPDM seals cover –40 °C to +120 °C. Special variants can be used up to +150 °C.
Can EPDM come into contact with chemicals? EPDM is insensitive to water, diluted acids and alkalis. For contact with oil and petrol, however, NBR or FKM should preferably be chosen.
How long do EPDM seals last outdoors? Under normal conditions the service life is 20 to 25 years, sometimes even longer.
Are there environmentally friendly alternatives? EPDM is already a sustainable choice due to its durability. In addition, manufacturers are increasingly developing recyclable variants that reduce the ecological footprint.
How does EPDM differ from silicone in practice? While silicone scores at very high temperatures, EPDM convinces through better mechanical load capacity and a more favourable price-performance ratio.
What role does the correct storage of EPDM seals play? Seals should be stored cool, dry and protected from light in order to preserve their properties over years.
Can EPDM also be used in combination with other materials? Yes, EPDM seals are often combined with metals, plastics or glass in order to create reliable sealing systems.
Our rubber sheets
For industry and trade we offer a wide variety of rubber sheets.
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Our high-quality SBR rubber sheet (styrene-butadiene rubber) is the solution for numerous industrial and commercial applications. This rubber sheet is manufactured from first-class styrene-butadiene rubber and is characterised by its outstanding physical properties.
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Discover the versatility and reliability of our EPDM rubber sheet, which is manufactured from ethylene propylene diene monomer (EPDM). This high-quality elastomer solution has been specially developed to meet the most demanding industrial and commercial applications.
NBR rubber sheet
The NBR rubber sheet is a high-quality industrial product that has been specially developed for applications where excellent resistance to oils, greases and various chemicals is required.
Viton rubber sheet
The Viton rubber sheet is a high-quality technical product that is used for a wide range of industrial applications. Manufactured from fluoro rubber (FKM), it offers outstanding properties that make it the ideal choice for extreme conditions.
FKM rubber sheet
The FKM rubber sheet is a high-quality technical product that is ideally suited for use in demanding industrial applications. Made from fluoro rubber (FKM), it is distinguished by a wide range of outstanding properties that make it the optimal choice for extreme operating conditions.
Silicone rubber sheet
The silicone rubber sheet is a first-class technical product that has been specially developed for applications that place high demands on temperature resistance and flexibility.
PUR rubber sheet
The PUR rubber sheet, manufactured from high-quality polyurethane, is a technically advanced product that has been developed for applications that place the highest demands on abrasion resistance and mechanical load capacity.
Neoprene rubber sheet
The neoprene rubber sheet, manufactured from high-quality chloroprene rubber (CR), is a versatile technical product that is ideally suited for a wide range of industrial and commercial applications.
