Description
The Marmox Thermoblock is a load bearing thermal insulation block that solves cold bridging at the wall–floor junction in house walls. A Marmox Thermoblock comprises of a 60mm thick core of fire resistant XPS insulation encasing two rows of high strength, low conductive, epoxy-concrete columns. These are fixed to the top and bottom surfaces of the block, which are 2.5mm thick layers of fibre reinforced polymer concrete incorporating the latest innovation in building technology – Carbon Nano Tubes.
A Marmox Thermoblock has a mean compressive strength of 9N/mm2 allowing it to be used under most load-bearing walls and its characteristic shear strength is 0.18N/mm2. Additionally, because they are impermeable to water they can be used in damp conditions without any loss of their insulating properties. So, not only do Thermoblocks reduce thermal bridging, they also create a moisture barrier.
A Marmox Thermoblock is NOT a thermal block/aerated block/AAC/aircrete block which are lightweight thermally insulating building blocks. A Marmox Thermoblock is a thermal bridging block, typically used at the base of a wall made of thermal, aerated blocks, specifically to eliminate the cold bridge.
Cold bridges occur where the wall meets the floor but until recently it was impossible to place insulation under a supporting wall because the insulation would have been crushed. It was for this reason that Marmox Thermoblock was developed. Thermoblock is a block of load-bearing insulation material with a thermal conductivity of 0.047W/mK strong enough to withstand a load of 9N/mm2. Its function is to eliminate or reduce the thermal bridge at the wall to floor junction.
A thermal bridge at the base of a wall will cause that wall’s surface to be colder. When there is little air movement, the chances of surface condensation and subsequently mould growth occurring are greatly increased. Mould growth is not only unsightly but can exacerbate health issues such as asthma and respiratory diseases. In drawing heat out of the wall, surface condensation can reduce the effectiveness of the wall insulation. Building Regulations require fRsi or the surface temperature factor to be greater than 0.75 in homes or greater than 0.5 in non-residential properties to ensure there will be no mould growth. Incorporating Marmox Thermoblock at the base of the internal wall will almost always result in fRsi values in excess of 0.75.
Marmox Thermoblock is available in 3 different sizes:
- 600 x 100 x 65mm
- 600 x 140 x 65mm
- 600 x 215 x 65mm
Important Installation Advice:
- Sealing the blocks together: Marmox MSP 360 sealant should be used to seal the ends of Marmox Thermoblocks together to prevent moisture creeping up between blocks and to ensure air tightness of the building.
- Not an alternative to aircrete blocks: Marmox Thermoblock should be used with, not instead of lightweight aircrete / thermal / AAC blocks. These blocks typically provide λ values between 0.11W/m.K (for 3.6N blocks) to 0.22W/m.K (for 7.3N blocks) whereas the Marmox Thermoblock’s λ value is 0.047 W/m.K.
- Not an alternative to a DPM: Although when sealed together Thermoblock creates a permanent waterproof barrier, a Damp Proof Membrane must be applied to the detail as though the Thermoblock were simply another normal block in the wall. The DPM can be fixed above or below the Thermoblock layer.
- Can a Thermoblock be laid on top of each other? No. All independent testing has been carried out with just one course of Thermoblock – we are unable to provide a characteristic compressive strength when more than one layer is used. In nearly all situations, the 65mm high version is sufficient in reducing the y value however a 100mm high version of Thermoblock is also available if necessary.
- What is fixed above or below the Thermoblock must NOT be narrower. The Marmox Thermoblock derives its strength from rows of concrete columns located along each side. What is sitting on top of a Thermoblock must therefore distribute its weight evenly over both sides. In other words, what’s on top (and below) the course of Thermoblock must not be narrower than the width of the Thermoblock.
- Can it be used as a Cavity Barrier? No, if used to bridge two combustible insulation materials the core material could melt creating a conduit for f lame to enter one living space from another. Therefore a cementitious covering such as a cement board should be fixed to one of the sides.
- How are Thermoblocks installed? Thermoblock can be cut on site using a brick saw, or through the polystyrene-only sections with a hand-saw. They are laid using ordinary bricklayers’ mortar.
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