Polystyrene Sheets

There are 2 main types of Polystyrene Sheets used as Insulating Building Materials – Expanded Polystyrene Sheets and Extruded Polystyrene Sheets. Expanded Polystyrene Sheets are generally white in colour and come in a range of types dependent on their compressive strength at 10% compression. The lowest performing polystyrene has a compressive strength of 50kPa (EPS50) while the highest performing expanded polystyrene has a compressive strength of 500kPa (EPS500). However the most common type of expanded polystyrene insulation sheets are EPS70 and EPS100 which have a compressive strength of 70kPa and 100kPA respectively. Expanded Polystyrene Sheets can be used to insulate floors, walls and ceilings however its most common application is for insulation under floor screeds.   Jablite, Kay-Metzeler and  Springvale are 3 of the manufacturers of Expanded  Polystyrene Insulation Sheets and are BBA certified on partial fill cavity and flooring insulation. Expanded Polystyrene is easy to handle and can be cut with a knife, is 100% recyclable, simple to install, cost effective and CFC and HCFC free. Expanded Polystyrene provides a thermal insulation  value of between 0.030 and 0.033 W/mK.

Extruded Polystyrene Sheets (or XEPS) can come in a variety of colours, thicknesses and types and is quite different to Expanded Polystyrene Sheets. While both are rigid, closed cell polystyrene sheets, Expanded Polystyrene is produced from solid beads of polystyrene. It is expanded by having small amounts of gas dissolved into the polystyrene during the manufacturing process. This is heated which causes the gas to expandand form the closed cells of EPS and increases it volume by around 40 times. Extruded Polystyrene Sheets start life as solid polystyrene crystals. Crystals, additives and a blowing agent are fed into an Extruder. Under high temperature and pressure the mixture is combined into a liquid and then forced through a die. As it comes out of the machine it expands, is shaped and cut  into a foam sheet.

Manufacturers of Extruded Polystyrene Sheets include Knauf, Dow, Cellecta and Kingspan. Extruded Polystyrene Insulation provides increased thermal insulation and greater resistance to both moisture and vapour. However an important point to note with XEPS is that the insulating gases contained within the foam, over time, seep out which has the effect of reducing its long term thermal insulating properties. By contrast the thermal insulation properties of Expanded Polystyrene Sheets remain constant for the lifetime of the product.

Once you have decided which type of Polystyrene Sheet you require, place your order online at www.buildingmaterials.co.uk and have it delivered anywhere in the United Kingdom. Delivery timescales can range from 3 working days upwards nationwide depending on the specific product in question.