The difference between Styrofoam and Styrodur insulation

• 1. EPS and XPS - further processed polystyrene
• 2. Properties of Styrofoam - EPS
• 3. Properties of Styrodur - XPS
  • 3.1. Colors of the manufacturer
• 4. Standards for thermal insulation materials
• 5. Application of Styrofoam (EPS)
  • 5.1. Wärmedämmverbundsystem
• 6. Application of Styrodur (XPS)
  • 6.1. Interior and core insulation
  • 6.2. Flat and inverted roof
• 7. Prices of insulation materials

Styrofoam and Styrodur are becoming increasingly popular thanks to subsidies for the thermal insulation of residential buildings. But hardly anyone actually knows what the difference is. The two practical insulation materials can be used as insulation for different purposes. Which insulation you use meaningfully for which purpose, we show here.

Although styrofoam and styrodur are both made of polystyrene, they later have different properties. These properties are caused by the way of manufacture. Here we show which of the two insulating materials is suitable for which purpose. So you always find the right insulation made of polystyrene, with which you achieve the greatest benefit in terms of insulation effect and savings potential. Here is the difference between Styrofoam and Styrodur.

1. EPS and XPS - further processed polystyrene

Both Styrofoam and Styrodur are made from polystyrene. Due to the manufacturing method, the two same materials are given a completely different structure. Styrodur, officially XPS is squeezed out and so filled with air. Polystyrene is pressed out in one go and thus gets a fine, uniform surface that can not be dissolved into individual flakes. At the same time, this structure makes the Styrodur more stable to pressure and very water-resistant, because hardly any moisture can penetrate into the fine surface. The different colors of XPS are assigned to the respective manufacturer.

• EPS = expanded polystyrene - inflated - Styrofoam
• XPS = extruded polystyrene - extruded - Styrodur

2. Properties of Styrofoam - EPS

Styrofoam, officially called EPS, is a kind of puffed-up polystyrene. The patent for it was already published in the fifties of the last century. The term Styrofoam is legally protected by BASF. Therefore, the term EPS will often appear in commerce if the product was not manufactured by BASF.

The production of polystyrene works in principle similar to the production of popcorn. A granulate of polystyrene polymerized with pentane, a blowing agent, is prefoamed at a high temperature of over 90 degrees. At this temperature, the propellant pentane is evaporated and the polystyrene granules inflates by 20 to 50 times to small foam particles. This creates the familiar little beads in polystyrene, which can be easily crumbled apart. Even at the production plant, the PS foam particles are formed into blocks, moldings or plates by a second treatment with hot steam. The temperature of the superheated steam treatment is between 110 and 120 degrees.

Depending on the purpose for which Styrofoam is to be used later, the mold is often already produced in the automatic system during the foaming process. The color is usually always white with EPS. The building code law envisages the enrichment with flame retardants for the protection of the inhabitants of the buildings, in which Styrofoam is installed. The material must comply with building material class B1 - flame retardant. However, EPS is not UV-resistant and turns slightly yellow when exposed to sunlight. The surface of the styrofoam becomes brittle and dries out visibly. The temperature resistance of EPS is between 70 and 85 degrees. In the short term Styropor can withstand a temperature of 100 degrees.

Some important facts:

• Temperature resistance 70 to 85 degrees / short term also 100 degrees
• Building material class B1 hardly inflammable
• Thermal conductivity 0.035 to 0.040 W / (mK)
• Water vapor diffusion resistance 20 to 100
• Bulk density between 10 and 35 kg / m³
• Compressive strength 0.070-0.260 N / mm²

3. Properties of Styrodur - XPS

Styrodur is produced as a continuous foam strand on so-called extrusion lines. The polystyrene is melted in the system and foamed by the addition of carbon dioxide. The carbon dioxide presses the Styrodur through slot dies, which can produce thicknesses between 20 millimeters and 20 centimeters. After the strand has emerged, the Styrodur must pass through a cooling zone.

In Germany, only the use of carbon dioxide CO2 is permitted. Partly halogenated hydrofluorocarbon, HCFC, which is still used abroad, may no longer be used as propellant in this country. Styrodur usually has a so-called foaming skin on the top surface of the plate. For certain applications, however, this foaming skin is removed and either left rough or provided with a waffle-shaped embossing of the surface. The material absorbs very little moisture and offers only little elasticity. Similar to styrofoam Styrodur is not UV resistant. However, it is also rotting resistant and very resistant to aging.

Some important facts:

• Temperature resistance 75 degrees long term
• Building material class B1 hardly inflammable
• Thermal conductivity 0.035 to 0.045 W / (m · K)
• Water vapor diffusion resistance 80 to 200
• Bulk density between 25 and 45 kg / m³
• Compressive strength 0.15-0.70 N / mm²

3.1. Colors of the manufacturer

While Styrofoam is usually white, Styrodur can have different colors. The colors can each be assigned to a specific manufacturer.

• green - BASF - Styrodur
• Purple - Jackon Insulation - Jackodur
• yellow - Ursa Germany GmbH - URSA XPS
• pink - Austrotherm XPS
• blue - Dow Chemical - Styrofoam

4. Standards for thermal insulation materials

For Styrofoam and Styrodur, the test regulations and quality guidelines of the Federal Quality Assurance Department must be met. The standard EN 13163 regulates thermal insulation materials for buildings made of expanded polystyrene, ie polystyrene.

• since March 2002 - DIN EN 13163 Thermal insulation products for buildings made of EPS
• DIN 18164-2 - Foamed plastics for insulation in construction / impact sound insulation
• expired since March 2003 - DIN 18164-1 insulation materials for thermal insulation

If you need or want to meet the requirements of the Energy Saving Ordinance, so that you may also receive the corresponding subsidies for subsequent insulation, you should observe the standards for the respective insulation on the one hand and the heat transfer coefficient on the other. For each insulation material is specified exactly with which insulation thickness of the required value is achieved.

5. Application of Styrofoam (EPS)

Styrofoam (EPS) is mainly offered in the form of boards as insulating material. For cavity insulation, however, EPS also exists as loose globules that are blown into the cavity. Another special form is often the impact sound insulation, which is offered on rolls for laminate, for example. For many of Styropor's original applications, Styrodur is clearly the better choice today. So it is with the impact sound insulation. Since polystyrene does not have the same compressive strength, it can not have the same effect.

• Flat roof insulation
• ETICS in the wall area
• Loose
• sound insulation
• Thermal insulation ceilings
• Perimeter insulation cellar

5.1. Wärmedämmverbundsystem

At many houses today you can see thick thermal insulation systems, or in short ETICS, whose core is thick polystyrene panels. These systems have been around since the mid-sixties, but only now, under the Energy Saving Ordinance, have they really got going. These dams are by no means undisputed and may raise new problems.

The polystyrene panels are either glued and / or pegged to the wall. Since the substrates are often not reliable, especially with very thick boards, the insulation is almost always pegged today. The Styrofoam plates in these systems are rather blocks that are about 14 inches thick. On these blocks comes a 1.5 to 5.0 millimeter thick reinforcement layer. A layer of glass fiber fabric is usually embedded in this reinforcing compound. This ensures that the later mineral plaster adheres to the new facade and the substrate is even.

Tip: Before you rely on a thermal insulation system, you should consider the many disadvantages and problems that have occurred in the meantime. In many cases, the damage far outweighed the benefits. Above all, the susceptibility due to mounting errors makes these systems quite unpopular. In addition, the composite system must later be disposed of as hazardous waste because the individual layers can not be separated again.

6. Application of Styrodur (XPS)

First and foremost, Styrodur is currently being used in residential buildings as perimeter insulation, eg. B. at the basement outer wall, used. Styrodur is ideally suited for the insulation of components that come into contact with the soil, because XPS does not rot. Due to its high compressive strength, the weight of the soil, which presses against a basement wall, can not affect the Styrodur, which is attached to the outer wall of the cellar. It is even possible to use Styrodur under the floor slab or in the groundwater area.

In soil insulation Styrodur is mainly used because of its compressive strength . Even in warehouses and production halls, floor constructions are insulated with Styrodur. XPS can withstand the highest loads caused by heavy machinery and production equipment.

Tip: Even if your private garage does not have to withstand these heavy loads, Styrodur is the perfect insulation for the floor slab. Other insulation materials under the concrete slab of the garage could possibly lead to cracks in the slab in a heavy car, as they can easily yield. The same applies to the insulation of a pool in your basement or garden. Here you should also put on the firmer Styrodur.

6.1. Interior and core insulation

If required, Styrodur can also be used in several layers inside the house. It neither deforms nor slips, as is the case, for example, with mineral or glass wool. Similarly optimal is a core insulation with Styrodur, since no air layer is necessary for the installation. This in turn is made possible by the rotting resistance of the material. So Styrodur can be placed directly between two wall layers without aging. Therefore, in addition to the core insulation, it is also used in the area of ​​thermal bridges. Styrodur can even be plastered later. However, only the embossed variant is recommended.

Floor slabs that are above heated rooms must now be imperatively insulated according to the German Energy Saving Ordinance. Initially, this regulation affected only floors that are not accessible. However, since 2012, walkable floors must be insulated if the space above is not inhabited. Since Styrodur can be laid out in several layers on the floor and is even walkable, it is better than Styrofoam or glass wool for this purpose.

6.2. Flat and inverted roof

Owners of a flat roof use Styrodur for roof insulation under the roofing felt. However, Styrodur can unleash its full potential on a reversed roof. Since with a reversed roof, the seal is under the insulation, the insulation layer must withstand constant moisture and moisture. In addition, by covering with gravel or stone slabs a high weight on the insulation, which can also wear only one layer of insulation with Styrodur permanently.

Almost without interruptions Styrodur can be used as a rafter insulation on a pitched roof. This is a simple and solid solution for the renovation of old buildings, if a new covering of the roof is provided anyway. Of course, the pitched roof insulation with Styrodur is also an energy-efficient and practical solution in new buildings.

• perimeter insulation
• floor insulation
• internal insulation
• Cavity wall insulation
• Cold bridge insulation
• Flat roof insulation
• inverted roof

Tip: Plan an artificial ice rink "> 7. Prices of insulation materials

Even though Styrofoam has been replaced in many areas by the Styrodur, it is often the financially cheaper solution. Even the white impact sound insulation on rollers is considerably cheaper than the green insulation, which is usually offered as plates from Styrodur. This principle continues in many areas. However, as with a composite thermal insulation system, it may be that a higher price is not worthwhile, because the savings are not higher. Here are some prices at a glance.

• Styrofoam 100 x 50 x 1.5 cm - about 1.80 euros
• Styrofoam 100 x 50 x 2 cm - about 2.50 euros
• Styrofoam 100 x 50 x 5 cm - about 4, 90 Euro
• Styrofoam 100 x 50 x 7 cm - about 6, 90 Euro
• Styrofoam 100 x 50 x 10 cm - about 8.50 Euro

• Impact Sound Styrofoam Rolled 25 square meters - per square meter about 0.80 euros
• Impact Sound Styrofoam Rolls 100 square meters - per square meter about 0.40 euros
• Footfall sound insulation Styrodur panels 10 square meters - per square meter about 1.70 euros

• Styrodur package 15 square meters - plate 125 x 60 x 2 cm - per square meter from about 4.00 euros
• Styrodur package 7.5 square meters - plate 125 x 60 x 4 cm - per square meter from about 7.00 euros
• Styrodur package 3.75 square meters - plate 125 x 60 x 8 cm - per square meter from about 25.00 euros

External thermal insulation composite ETICS with Styrofoam

• smooth solid surface - square meters from 90 euros
• old flush or many angles and corners - square meters from 120 euros
• Old building with decorated facades - square meters from 150 euros

Tips for quick readers

• Styrofoam (EPS) - steam-blown polystyrene
  • Structure of small beads
  • Beads are easily detached from each other
  • very favorable insulation solution
  • EPS is often displaced by Styrodur
  • Compressive strength not sufficient for floor laying
• Styrodur (XPS) - extruded polystyrene
  • very fine structure of the surface
  • fine-pored material - partially provided with honeycomb structure
  • Honeycomb structure can be plastered
  • stronger pressure resistance - walkable
  • Insensitive to moisture - do not rot
  • Flat and inverted roof insulation / steep roof insulation
  • Use as perimeter insulation in the floor area
  • Styrodur even possible under floor slabs