EXPANDED POLYSTYRENE BOARDS

EPS (Expanded PolyStyrene) is a closed cell, thermoplastic foam material made of 98% air and just 2% plastic. This high percentage of trapped air makes it an excellent premier insulator. Polystyrene sheets are mostly used for building insulation. They come in the form of panels that are installed under roofing and wall cavities or sidings. It is widely used in the building construction industry because it is so versatile. It can be used on below grade for insulated vinyl siding, insulated concrete forms or blocks, structurally insulated panels know as SIP’s and most importantly on Exterior Insulation Systems such as K-Rend. EPS has many advantages. The big advantage of EPS is that it has no thermal drifts or loss of R-Value over the time. There is also no off-casting on site because the blowing agents are trapped inside the polystyrene beads. Since it is impermeable to water, it is mold and mildew resistant. In fact, EPS leads the other insulation products when it comes to R-value per £. This ratio of R-value to the total price of manufacturing and installation per sq. m of material is a crucial component of the process to deliver a budget-friendly, energy-efficient finished home or building. The manufacturing costs of EPS are generally lower compared to other insulating materials like PIR or Phenolic Boards. The EPS board may seem like a simple EWI insulation material but in reality, it is strong and has been used around the globe for decades. 

Polystyrene board is a very practical, economic and efficient insulation product which can be applied to all areas of building construction to provide superior standards of thermal insulation. The closed-cell nature of EPS means it is a cost effective yet durable product and is lightweight, non-toxic, and is completely recyclable. EPS has been proven to remain strong even after decades of use. A report published by EUMEPS in its EPS briefing found that after several strength tests, EPS that had been in the ground for 30 years showed absolutely no loss of strength. Cold flow was also found to be significantly less than expected with long-term exposure to sustained loading. Micro cellular closed cell construction provides EPS with its excellent insulating and shock absorbing characteristics. EPS has very poor water absorption which decreases as density increases.The cellular structure of EPS is water resistant, vapor permeable and possesses zero capillarity though neither liquid water nor water vapor influences its mechanical properties, however it can attract termites and ants.

POLYSTYRENE GRADES ǀ APPLICATION

Expanded polystyrene material can easily be used to achieve low energy building standards and is available in a variety of densities depending on the needs of your project. When deciding which grade of EPS to use, the density of a block is often the most important factor. The EPS product is classified based on compressive strength and compressive stress. Compressive strength determines what the grade of EPS is. In fact, it is the maximum uniaxial compressive stress that material can bear before fracturing. Number is assigned to EPS product based on its compressive stress at 10% compression. Generally, the thermal conductivity of EPS core decreases as its density increases.

Wide range of applications comes with a wide range of polystyrene grades available. Determining which grade of polystyrene best suits your needs can be difficult. Industry-wide terms used for differing grades include:

• Low Weight ǀ LD ǀ EPS 50 ǀ Density 50 kPa ǀ Can be used as a cost effective general packaging ǀ Insulation & display ǀ Decorative molding
• Medium ǀ SD ǀ EPS 70 ǀ Density 70 kPa ǀ Can be used in a variety of floor applications both domestic and industrial ǀ Cavity Wall Insulation ǀ External Wall Insulation Systems ǀ EWI boards ǀ Wall and Attic applications ǀ Reinforced render systems
• Heavy ǀ HD ǀ EPS 100 ǀ Density 100 kPa ǀ Can be used as a void former ǀ Fill material ǀ Floor applications ǀ Underfloor heating insulation
• Extra Heavy ǀ EHD ǀ EPS 150 ǀ Density 150 kPa ǀ Can be used as a void former ǀ Floor Pile collars ǀ Column formers ǀ Insulated foundation systems ǀ Concrete floor
• Ultra-Heavy Weight ǀ UHD ǀ EPS 200 ǀ Density 200 kPa ǀ Can be used for insulating garage floor ǀ Flooring under slab ǀ Structural insulated panels (SIPs) ǀ Road and Bridge works ǀ Slope stabilization of mountainous terrain
• Ultra Ultra High Density ǀ UUHD ǀ Density 300 kPa ǀ Can be used in insulated foundation applications with heavy loading such as Embankments back filling ǀ Bridge abutment ǀ Road widening

POLYSTYRENE PRODUCTION PROCESS

Expanded polystyrene is a common insulating material obtained from expanded polystyrene granules. In the production process, air-filled spheres are created, which are then forced into a mold, where they are formed into a block. Depending on the degree of foaming, polystyrene of different densities is obtained. As a standard, a block of polystyrene is cut with the hot wire method, creating boards of various lengths and thicknesses.

In the first stage of production, known as pre-expansion, the expandable polystyrene is exposed to steam and high temperature. This makes the granulate several times larger in volume. It is transported to special silos, where it is seasoned for several hours. Thanks to this, its structure stabilizes. In the next stage, the seasoned pearls go to the machine, which again, under the influence of steam and high temperature, forms them into large cuboids, the so-called polystyrene blocks. EPS does not use any CFCS, chlorofluorocarbons or hydrohlorofluorocarbons in the blowing process. It is also 100% recyclable.

WHICH EXPANDED POLYSTYRENE IS BEST FOR ME. WHITE, GREY OR PERHAPS XPS?

Two of the most frequently installed types of rigid foam insulation are expanded and extruded polystyrene (EPS and XPS). Each product has proponents claiming one out performs the other. However, it is key to understand each product may be more suited for a particular use than the other. In addition to the different densities of EPS that can be manufactured, Expanded Polystyrene is offered in different grades and colours of material that affect its thermal performance. Either white or grey expandable polystyrene boards can be used as part of a render system to provide an efficient and cost effective solution. While both are polystyrene products and are used for some similar applications, that is where the similarity stops. 

White EPS, while still offering a high thermal performance, requires slightly thicker levels to achieve the same thermal performance as graphite-enhanced grey EPS. For example, while a project may call for 120mm of white EPS, the same thermal performance can be achieved with 90mm of grey (graphite) EPS. White EPS is said to be slightly easier to work with when installing external wall insulation systems. This is because white EPS reflects the sun better than grey EPS, meaning it’s not necessary to rasp the insulation, as it will not become as “greasy” when exposed to the sun’s heat. Taking this step out of the installation of external wall insulation can save several hours and cut costs for the contractor and customer, however, grey EPS is still used in the majority of cases as a higher thermal performance can be achieved with less material.

Grey EPS is mainly intended for investors who want to achieve the standard of an energy-saving or passive house. The difference between white and grey polystyrene is the presence of graphite, which is added to the expanded polystyrene during the production process. As a result, you get polystyrene with a grey tint, but more importantly - also with increased thermal insulation properties. It allows the use of a thinner layer of insulation without compromising the insulation parameters of the wall. The technical conditions regarding the maximum heat transfer coefficient through external walls mean that investors are forced to insulate their houses with thicker and thicker layers of insulation. 

XPS board is actually fairly inexpensive non organic styrofoam material. Chemically it’s made up of the same as EPS polystyrene but rather than being formed into droplets and then expanded, it is foamed up. The production process of extruded polystyrene is only slightly different from expanded polystyrene. The liquid form is mixed with additives and blowing agents and then extruded through a dye. It is then expanded during the cooling process. This produces a tightly packed closed cell insulation called XPS. Just like EPS, XPS is made of 98% air and just 2 % plastic. Blue XPS is made by Styrofoam and Dow Company, green XPS called GreenGuard is made by Kingspan and yellow XPS is made by Soprema. While they are all the same, the colour helps distinguish manufacturing companies on job sites. Since the cells of XPS are so tightly packed, it is more moisture resistant and mildew resistant then EPS. So it is often selected in water environments. The compressive strength of XPS is also greater than the EPS reaching 300-500 kPa. Similar to EPS there is no thermal drift or loss of R-Value over time. The thermal insulation performance of EPS and XPS in identical densities is quite close. However, EPS with the same level of density is less expensive. Finally it is 100% recyclable. It is also very versatile, it can be used below slab and basement walls. XPS panels are also coated in the same bromine fire retardant as EPS panels. XPS can also attract ants and termites even though it is not an organic material. 

EXPANDED POLYSTYRENE THICKNESSES

These EPS insulation boards are available in an extensive range of grades and sizes to suit your requirements, as well as multiple thicknesses ranging from 10mm to 100mm. 

10mm ǀ 20mm ǀ 25mm ǀ 30mm ǀ 50mm ǀ 100mm

Video credit:https://www.youtube.com/watch?v=N1juCG6adcI&t=124s