What is Extruded Polystyrene (XPS)?
Extruded polystyrene is a type of plastic used to make products ranging from building materials to storage containers. This product may also be referred to as XPS. Manufacturers make polystyrene from hydrocarbon molecules, which are a by-product of the petroleum refining process. The polystyrene particles are then melted at high temperatures, then infused with air. This mixture is placed into a mold, where it is allowed to cool and harden. It may also be subject to a more traditional extrusion process, during which is it pressed through a die to form the desired shape.
Is XPS a brand new product?
No, it has been in use all over the world since 1940's. In a few countries, XPS insulation is mandatory without which electricity connections will NOT be provided by their governments.
Should I get weathering course treatment done if I am using XPS boards for insulation?
If you are insulating your roof with XPS boards, then you do not have to get any kind of weathering course treatment done. XPS insulation replaces ALL traditional weathering treatments
What is the difference between XPS insulation & Brick Jelly treatment?
Technically XPS insulation & brick jelly treatment cannot be compared. They are like chalk and cheese. Click here for a comparative chart for a tested analysis.
Can I walk over it or place heavy items like an AC unit for example?
Yes, as far as the weight is NOT point load. It has a capacity to hold 2.75 tons per sq meter due to the compressive strength of 300 kpa (as per DIN 53421 standards)
Can XPS be exposed to the sun?
No, it loses its form. it has to be covered with cement mortar as the final roof surface ie if you do not want to install tiles.
Over the roof slab, is it water proofing first or insulation?
Over the mother slab, you have to get a water proofing done & then get the insulation done over the WP layer. This will enhance the longevity of the WP treatment as no heat reaches the WP layer. Most of the WP layers crack up due to excessive heat over a few seasons but if you insulate it, then its protected for a few decades.
Why is XPS the best rigid form of insulation?
The reason why Extruded Polystyrene is the best rigid insulation material is because it boasts of an excellent thermal conductivity of 0.028 w/mk, compressive strength of 300 kpa & less than 1% absorption of water.
What about white tiles, cool coating & other products?
When it comes to thermal conductivity numbers, white tiles (0.1998) are 8 times lesser efficient than XPS insulation (0.028). Logically speaking, any material continuously exposed to the sun will lose its efficiency in a few seasons. Local applicators have to replace or re-coat the applied treatment again to re-gain its original effect which will eventually wear away again.
What is my return of investment (ROI)
Firstly, since almost no heat reaches the roof slab (via the insulated layer), thermal stress is minimal. Secondly, your water proofing layer does not crack as heat does not reach the same. Thirdly you save on electricity bills related to AC units as its usage will be bare minimum. In short, you save monies & also save your roof slab from any kind of deterioration which is your best ROI