expanded polystyrene Thermaroof:

Thermaroof involves placing insulation above the roofing membrane rather than below it. The lightweight EPS sheets, which make the Thermaroof system, are quick and easy to install requiring minimal labour. It also offers superior drainage protection. The underside of each sheet incorporates a grid of small channels and positive location lugs providing a continuity of drainage channels sheet to sheet.

The thermal resistance (R value) of Thermaroof insulation is permanent because the cellular structure of Thermaroof contains only stabilised air. Ageing has no effect on the performance of Thermaroof. Thermaroof provides high R values per dollar and allows for very cost effective design.

The effect of moisture on an insulating material is only important in so far as that moisture adversely affects the physical and thermal properties of the insulation. It is the change in physical and thermal properties that has to be measured, not the amount of water absorbed. Thermaroof has excellent resistance to moisture absorption in water. Moisture gain in Thermaroof is either surface or interstitial due to Thermaroof’s closed cell structure of hydrophobic polymer and its integrally moulded skin - thus moisture gain has limited effect on thermal resistance values.

Thermaroof also offers a high degree of dimensional stability in wet conditions. For R1.25 H grade Thermaroof, submersion tests to ASTM C-272 (30mm head of water) for 25 days produce a maximum uptake of 6% moisture vol/vol. Tests carried out by the Cold Regions Research and Engineering Laboratory of the U.S Army Corps of Engineers show a 90% retention of dry R value at a 6% vol/vol moisture content. As R1.25 H grade is the thinnest Thermaroof product on offer, performance figures from other Thermaroof panels will be improved on those shown in this test.

The 8mm x 4mm channels moulded as a grid pattern into the underside of the Thermaroof panels allow easy drainage across the top of the membrane. This unique product feature coupled with adequate roof design will prevent prolonged water/insulation contact. Positive location lugs moulded into the ship-lap edges ensure continuity of the drainage channels board to board. In extraordinary circumstance where water ponded to a height of 30mm above the insulation for periods in excess of 25 days, there would only be a possible 10% reduction of the insulation's R value.

Thermaroof is able to withstand the abuse of temperature cycling, assuring long term performance without loss of structural integrity or physical properties. The correct grade of Thermaroof can be selected by the designer to withstand the loads of ballast, foot traffic and equipment that will be on the roof. Thermaroof exhibits excellent compressive and flexural strength and dimensional stability characteristics at a high strength to weight ratio. The range of classes available enables the specifier to select the most appropriate balance between structural and insulating properties, and cost, for any building application.

Although Thermaroof has a low water vapour transmission, it is not a vapour barrier; instead it "breathes". Because it does not trap moisture, Thermaroof does not need costly venting as do certain other relatively impermeable insulation materials. Thermaroof insulation, being made from expanded polystyrene (EPS), is an inert, organic material. It provides no nutritive value to plants, animals or micro organisms. It will not rot and is highly resistant to mildew. Thermaroof insulation can be installed quickly and easily, requiring limited labour. It can be cut to shape with knife or saw to assure a tight fit and eliminate heat loss channels. Its light weight allows ease in handling and storage.