Meir Roofing

Interlocking extruded polystyrene panels are available with a decorative cementitious surfacing to provide an inverted roof which is lightweight and will need additional loading. The interlock ensures safety against wind forces within limits prescribed by the manufacturers.   A special grade of panel is available with a reinforced decorative cementitious surfacing for pedestrian terrace decks. This surface is suitable for foot traffic only or light maintenance traffic.   Extruded polystyrene (XPS) cement topped board creates a lightweight protected roof offering high compressive strength, easily achievable U-values with minimum board thickness, required fire performance for the intended application, resistance to both moisture and water vapour ingress, is unaffected by air movement, is safe and easy to install and provides reliable long term thermal performance over the lifetime of the building and zero Ozone Depletion potential.    Additional benefits include additional dead loading is kept to a minimum, excellent resistance to wind uplift and is ideal for new build and refurbishment.

Composite boards consist of insulation products which individually are suitable for roofing. The long term bond strength between the materials should be at least as strong as the de-lamination strength of the weakest individual component.   The composite board should be free from warping, bowing and be dimensionally stable both during application and in service.   Rigid urethane and phenolic foams are to some extent heat sensitive.   They can be formulated to withstand the heat of mastic asphalt, but are much more heat resistant in composite form with a facing of cork, Perlite or fibreboard.   The facing is also suitable to receive a full bond of the first layer of built-up roofing, and this eliminates the need for BS 747 type vented base layer to provide a partial bond.   The cost saving from omitting this type of material can be set off against the extra cost of forming a composite and can lead to an economic overall specification with useful technical advantages.

CORK/URETHANE COMPOSITE BOARDS

A cork insulation layer can be added to rigid urethane as a facing to form a composite board. This has the advantage of offering a cork surface for the application of the waterproofing. Built up roofing can be bonded direct without the use of a vented base layer, and the cork is an ideal heat resistant surface to receive mastic asphalt.   Cork/urethane composites are frequently used cut to falls to provide a tapered insulation system.

PERLITE/URETHANE COMPOSITE BOARDS

The Perlite surface allows a full bond for built-up roofing. But Perlite has a relatively low laminar strength and the specification may need mechanical fixing through the first layer of roofing when a roof is exposed to high winds, in just the same way as for normal Perlite boards.

PERLITE/PHENOLIC COMPOSITE BOARDS

This composite brings together two materials with improved fire characteristics, and resistance to high temperatures. Due to the low laminar strength of Perlite, mechanical fixings may be required on exposed sites.   Perlite/phenolic composite is suitable for fully bonded built-up roofing, and for mastic asphalt

FIBREBOARD/POLYSTYRENE COMPOSITE BOARDS

Expanded bead polystyrene is extremely heat sensitive and must always be overlaid with a heat resistant insulation before application of built-up roofing or mastic asphalt. The composite board combines the overlay into a single board and forms a low cost insulation suitable for full bonded built-up roofing and asphalt.   Particular care is necessary to install the composite with tight joints between boards and at abutments to prevent damage from hot bitumen penetrating the joints or radiant heat from mastic asphalt when it is applied.   Fibreboard/polystyrene composite is frequently used cut to falls in a tapered insulation roof drainage system.

Is a well established and proven insulation material formed from pure granulated cork, compressed, steam baked and held together by the natural cork gum.  It is widely used as a heat resistant and stable facing to rigid urethane insulation to form a composite insulation, is resistant to moisture and decay and is suitable for use above high humidity conditions.

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The tapered roof system is installed on flat roof decks and is designed to provide a positive slope to facilitate roof drainage avoid ponding.   We offer survey, design, fabrication and supply of tapered roof insulation schemes which provide tailored and bespoke solutions to flat roofs whilst taking into consideration current regulations and cost/ budget criteria.   Available in Rigid Polyurethane and Polyisocyranate, Extruded Polystyrene XPS, Expanded Polystyrene EPS, Cork and Cork Composites, Rock-Mineral Fibre, Foamglass.

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Expanded polystyrene boards are formed by a steam heated process which expands the beads of polystyrene and fuses them into a slab. Boards are available in various grades and are available with a pre-felted upper surface factory bonded fibreboard or Perlite board for use in roofing applications which has the dual function of shielding the expanded polystyrene from hot bitumen and asphalt and absorbing the thermal movement sufficiently to permit a fully bonded built-up roofing system. Expanded polystyrene boards exhibit large thermal movement and are heat sensitive. The boards cannot tolerate the temperatures which arise from the direct application of hot bitumen or asphalt and indirect laying techniques have to be adopted by applying coat hot bitumen to the substrate and allowing it to cool to a tacky condition before the expanded polystyrene is laid or a colds applied adhesive is used. The boards are available as a constant thickness or tapered to provide falls.

Extruded polystyrene boards have similar thermal movement and heat sensitivity characteristics to expanded polystyrene but have an improved thermal conductivity, low water absorption, high compressive strength, is flame-retardant, reduces thermal stress and saves heating and cooling energy. When selecting a thickness to achieve a specific U-value for an inverted roof, it is necessary to allow for the loss in efficiency due to the cooling effect caused by water draining through the insulation. The normal method to take this into account is to add 20% to the thickness of the board. The cooling effect can be reduced by the use of a suitable waterproofing membrane laid on the top of the insulation.   It is suitable for a number of applications including walls, floors, car park, high compressive strength applications and because of its exceptionally resistant to water absorption is suitable in an inverted roof system. Application in the protected membrane roof system consists of laying the boards loose above the waterproofing with anchorage against wind uplift and protection from ultra-violet degradation provided by a loading coat of gravel with a minimum size in the order of 20mm or paving slabs. A suitable loose laid geo-textile underlay may also be applied to even out surface irregularities or, if the waterproofing has a rough or sharp surface, to prevent abrasion to the underside of the board. Fine granules can work their way through the joints of the insulation and can cause damage and instability if they accumulate on the underside of the insulation. If it is expected that significant quantities of fine gravel will be present, it will be necessary to add a filter layer on top of the in addition to the waterproofing membrane insulation to act as a sieve and prevent the passage of fine material through the joints blowing under them
Interlocking extruded polystyrene panels are available with a decorative cementitious surfacing, to provide an inverted roof which is light weight, but will not need additional loading. The interlock ensures safety against wind forces within limits prescribed by the manufacturers. A special grade of panel is available with a reinforced decorative cementitious surfacing for pedestrian terrace decks. This surface is suitable for foot traffic only or light maintenance traffic. It is desirable to provide an even substrate which is free of undulations and which provides a continuous support for the panels. This will reduce the risk of panel breakage under foot traffic. The roof system must be impermeable and secure against wind. Panels must be protected from wind, edges against parapets and abutments should have panels set back about 50mm and the space filled with clean gravel. Panel joints are set open by 1mm to allow for thermal movement. The roof waterproofing should be installed to falls to prevent significant ponding, which could give rise to the flotation of the panels which may result in the need to install additional loading to prevent floatation. In all cases the detail of design and application must be in accordance with the manufacturer’s instructions

Cellular glass is made from pure glass, expanded during manufacture and formed into slabs which are inorganic, resistant to attack by birds and vermin, almost impermeable to water, will not gain moisture by vapour diffusion, will not rot or decay and is non-combustible. It can be laid without a vapour barrier, provided that the joints are sealed in bitumen according to the manufacturer’s instructions. Cellular glass provides a stable base for mastic asphalt and fully bonded built-up roofing. When mastic asphalt is applied, two layers of loose laid non-bituminised paper are required between the slabs and the sheathing felt isolating membrane to prevent adhesion of the asphalt. Slabs are available in constant thicknesses or tapered to provide falls and suitable for roofs, floors, and walls and is available in cut to falls.

Thermo-Hemp® is a high-quality product distinguished by its excellent technical qualities according to the effectivenorms. The European Technical Approval was issued by the German Institute for Constructional Engineering in Berlin under the registration number ETA-05/0037.

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Mineral wool is manufactured from volcanic rock, melted at extremely high temperatures. The molten rock is then directed onto a series of rotating wheels where it is converted into thin fibres and during the process a resin is added to act as a binding agent. The fibres are gathered together to form a mat, which is then cured and compressed to form a rigid insulation slab which provides a good level of thermal insulation is dimensionally stable substrate has excellent compressive with high laminar strengths and a high resistance to combustion. Various types of facings are factory bonded onto the slabs to one side to control the surface absorption of bitumen allowing it to be used for flat roofing. It is available in flat and cut to falls systems.

A naturally occurring volcanic rock formed when cooling molten magna comes into contact with water and which causes powdered Perlite to expand some 20 times when heated. During manufacture, the Perlite is combined with mineral fibres and binders to produce a roof board that is incombustible, thermally insulating, have a good compressive strength but low laminar strength, are rather brittle, whilst being ecologically friendly and resists decay but the absorption of moisture can cause significant loss of strength chemically neutral and rot proof. One surface of Perlite board is usually treated during manufacture with a bitumen emulsion to increase resistance to bitumen absorption and bind the surface. They have a very low coefficient of thermal expansion and will accept fully bonded waterproofing systems. Because of the dimensional stability and heat shielding qualities it often used to improve the performance of other insulants such as polystyrene, rigid urethane or phenolic either as an on site overlay to these materials or fully bonded composite form with a minimum 25mm thickness being recommended. It is used extensively where fire protection or high compressive strength is required.

Phenolic foam is similar in structure to rigid urethane foams, and needs to conform to internationally agreed ODP levels. An extremely small cell size is possible, and leads to an improved λ value. The cell walls tend to be friable, which makes the foam rather vulnerable to damage but formulations are rapidly improving.   The advantage of phenolic foam is a greater resistance to high temperature than other foams, and the possibility of improved performance in a fire.   In other respects phenolic foam is similar to rigid urethane.

Environmentally friendly polyurethane boards (PUR) and (PIR) boards are foamed with an inert gas or blowing agent that is locked into the cells and gives the board’s better insulation characteristics than foams which have air filled cells. The blowing agent must conform to internationally agreed levels of ozone depletion potential (ODP) and some blowing agents can only be regarded as transitional until all materials are developed to contain no significant ODP. There is no agreed definition of PUR and PIR formulations, but the term PIR type is used to describe rigid urethane foam with increased resistance to high temperatures, sufficient to withstand the heat of mastic asphalt on application. The cell walls are slightly permeable to air and over a period of several years the air will diffuse into the cells until it reaches atmospheric pressure. The thermal efficiency of the foam decreases over this period and this should be allowed for in the figures published for thermal conductivity. A suitable test for thermal conductivity of aged material is the ACERMI test from France and manufacturers should be asked to confirm that their quoted thermal conductivity properly allows for long term ageing. A selection of facings for differing waterproofing systems, flat, composite or profiled boards and cut to falls to ensure that all requirements are satisfied. Unfaced rigid urethane foam is likely to suffer movement from changing temperature and conditions. A glass tissue facing is therefore used to control the foam and produce a stable board to receive built-up roofing and asphalt. Board for built-up roofing is normally faced with perforated layer of bitumen coated glass tissue for good part-bonding of membranes and the board for asphalt is faced with glass tissue only. Partial bonding is not suitable for sloping roofs and a cork or fibreboard overlay should be added to allow a fully bonded system

AlumTech is a radiant insulation for application on both flat and pich roofs. It is made of two layers of air bubble polythylene, wedge-welded for a width of 15mm and covered by a film of low emission aluminium on both sides. The materials used to make AlumTech are absolutely safe, non-toxic and non-harmful.

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Has good compressive and laminar strength and a very low coefficient of thermal expansion is used as a low cost heat protection facing for insulation material, is a low cost overlay board for re-roofing and provides a satisfactory base for mastic asphalt waterproofing or fully bonded built-up roofing, but it is vulnerable to decay if it becomes damp and moisture absorption can cause significant movement and may cause ridging of the waterproofing over the joints.   It is no longer widely used as insulation because it has insufficient performance for modern requirements.