PIR RIGID FLOOR INSULATION

PIR floor insulation (Polyisocyanurate) called POLYISO is a thermoset plastic produced as a foam and used as rigid thermal insulation especially in floor applications. The term rigid insulation typically refers to the large pre-formed sheets of insulation which can be bought in 2400mm x 1200mm (8’ x 4’) size. Board insulation is created via a continuous foaming process that creates a tight cell structure and an inseparable bond between the foil and board. Rigid Insulation boards have a low thermal conductivity, which means less of the product is needed to achieve the desired thermal resistance and the tight-cell, rigid construction is designed for longevity. The insulation boards are also produced with a zero ozone depletion blowing agent. These boards are available in a wide variety of thicknesses from 12mm to 200mm, allowing you to achieve the desired level of insulation in the floor. Cutting of the boards is to be carried out using a fine toothed saw in a ventilated area. To find out on how to cut PIR floor boards click here. Thinner thicknesses of board can also be cut with a fine toothed saw. Alternatively thinner thicknesses can also be cut by scoring the boards with a sharp knife, snapping the board over a straight edge and then cutting the facing on the other side. PIR thermal board could be installed directly under the floorboards with no other materials required. The most important reason to use PIR rigid board for floors is its tightness, cutting and high thermal properties. The Lambda value of PIR is situated between 0.021 to 0.032 W/mK. This means that PIR offers superior insulation with the same thickness. In other words, the insulation layer is thinner and more efficient, leaving more available space. Moreover, boards are simply a better solution, enabling greater savings and better thermal insulation than standard polystyrene or mineral wool. 

PIR FLOOR BOARD MANUFACTURING PROCESS

PIR insulation boards are made by reacting a liquid polyol with a liquid polymeric isocyanate known as MDI in the presence of a blowing agent and other additives. The mixed components then react exothermally to form a rigid thermosetting polymer. Since the blowing agent evaporates during this reaction a rigid closed cell low density insulation product is created. Excellent insulation performance is achieved because the gas trapped within the closed cell structure has a very low thermal conductivity and there is minimal heat conduction through the solid cell walls due to the low density. Approximately 97% of the volume of the foam is trapped gas. The manufacture of Polyisocyanurate Foam (PIR) insulation is a continuous lamination process onto facing materials. The facers top and bottom are tailored to match end use, foil faced and glass tissue are the most common.

MOST COMMON PIR BOARDS USED FOR FLOORS

PIR boards are one of the most popular forms of floor insulation available. Polyisocyanurate panels are a good solution to insulate floors, as they meet the insulation levels required by current building regulations, where the U-value of 0.25 W/m2K must be met. The most common recognised PIR brands are Celotex and its GA/TB/XR4000 range followed by Recticel and Unilin Thin-R. Also thermafloor TF70 boards made by Kingspan group, are used in UK constructions, however, they will likely be the most expensive of all the brand options. Rigid polyisocyanurate (PIR) foam insulation boards such as Celotex XR4000 and GA4000 are among the most thermally efficient and commonly available insulation materials on the market.

PIR INSTALLATION BETWEEN FLOOR JOISTS

Arguably the most popular floor solution, installing insulation between the floor joists uses the depth of the structural timbers to best effect. Using a thermally efficient material to get the maximum benefit from as much of the floor joist depth as possible means the under - floor insulation layer can be kept to a minimum, making installation easier. Adding another layer of insulation, either above or below the floor joists gives another key advantage – it reduces the effect of cold bridging through the timber joists. The level of thermal performance required then dictates the thickness of insulation required below the floor joists - usually anything from 80mm to 120mm of PIR foam. That can be a general application board Unilin XT/UF can be considered followed by a separate plasterboard. Alternatively, using a thermal laminate featuring rigid PIR insulation pre-bonded to a plasterboard such as Unilin XT/TL means fitting the insulation and ceiling lining in one operation, reducing storage, cutting and fixing.

Video credit:https://www.youtube.com/watch?v=HDhhyS5r8QE

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