Roundtower SuperTherm

Roundtower SuperTherm Plaster is an ultra lightweight and highly insulating plaster for internal applications. It is a dry ready mixed highly Insulating Lime Plaster designed for internal use to significantly reduce thermal losses in masonry.

In a market filled with insulating plasters, SuperTherm outperforms them all—not just in insulation but across all key performance areas that matter to you and your clients.

Unmatched Thermal Performance:

• Superior Insulation: With a K-value of 0.0395, SuperTherm is three times more thermally efficient than our existing Roundtower Insulating Pender.
• Space-Saving Efficiency: A 13mm layer of SuperTherm provides the same insulation as a 50mm layer of Roundtower Insulating Plaster, allowing for considerably thinner applications without compromising on performance, which we deem especially valuable for vernacular buildings with limited internal floor space.

Advanced Moisture Management:

• Enhanced Vapour Permeability: Boasting a μ value of 4.2, SuperTherm is 35% more vapour permeable than our current insulating render and 70% better than standard NHL plasters.
• Superior Moisture Handling: With a water carrying capacity of 225 kg/m³, it's 65% higher than our existing product and 131% better than standard NHL3.5 plaster, ensuring optimal moisture regulation and condensation control.
• The moisture buffering capabilities that have been proven with the current insulating plaster become significantly enhanced.

Innovative Composition:

• Cutting-Edge Aggregate: The plaster utilises an ultra-lightweight foamed manufactured aggregate with a nanometre pore structure. This design traps air at the molecular level, dramatically reducing heat transfer.
• Environmentally Friendly: The aggregate is free from halogens, VOCs, and toxic heavy metals. Produced in a carbon-neutral process, it can be recycled at end-of-life, retaining its high thermal performance.

Lightweight Yet Durable:

• Low Density, High Performance: At just 260 kg/m³, SuperTherm is 31% lighter than the market-leading insulating plaster, yet it doesn't compromise on strength.
• Robust Strength: With a compressive strength of 3.014 N, it's suitable for soft masonry and durable enough for commercial applications. Remarkably, a 40×40×80 mm bar can support the weight of an adult male without breaking. I weighed 91kg this morning (don’t laugh) and I stood on a bar mould and it did not break. I would suggest trying the same with the current product or a competitor (if you have a mould) just to see the difference in strength.

Environmental Benefits:

• High CO₂ Reabsorption: SuperTherm absorbs around 39% of its weight as CO₂—a 62.5% improvement over our existing insulating plaster.
• Future Innovations: We are exploring the use of recycled household waste in our production process to further enhance our environmental credentials.

UK Manufacturing

• Within a crowded market, there is no UK manufacturer of insulation plasters that can achieve this level of performance, with SuperTherm we have changed this.

‍

Benefits:

• K Value – 0.0395
• Significantly warmer buildings
• Reduced heating costs
• Management of relative humidity and condensation within living areas
• Lightweight and easy to apply
• Density – 250kg m/3
• Sustainable and environmentally friendly plaster
• Consistency of product compared to site mixed alternatives

‍

Roundtower SuperTherm Usage:

SuperTherm is an extremely low density and highly insulating plaster designed to significantly improve the thermal performance of masonry.

SuperTherm excels as a remarkably low density, high insulation material, offering superior mechanical resistance relative to other products with similar density and thermal characteristics.

It delivers outstanding thermal insulation for masonry and can achieve this at much thinner layers, whilst also maintaining exceptional vapour permeability.

SuperTherm offers a viable solution for Part L legislation in that it meets the requirements for improving the thermal performance of a wall, whilst maintaining a permeable fabric which absorbs and readily allows for the evaporation of moisture.

With a measured K Value of 0.0395, a 50mm application of Insulating Render will improve the U value of a solid wall by 115% or more, significantly reducing heat loss.

Fibre additions improve the flexural strength of the render, distributing stresses across the render to help reduce point loading, and negate the need for any mesh to be applied to the wall or inserted within the render.

Due to its lightweight nature, SuperTherm can be applied at depths of up to 50mm per pass.

It can also be applied green on green through to the finish with appropriate sucxtion, making the application significantly easier and faster than most available plasters

SuperTherm can also be used in sustainable construction and renovation projects as a basecoat onto building materials such as hemp, straw, rammed earth, Woodfibre boards (and plasterboard TBC). The insulating properties help reduce the thermal expansion differentials between the background and any subsequent coatings.

For internal applications it should be applied as backing coat/s and finished with SuperTherm Finishing Plaster.

Suitable for application onto most host surfaces with suction.

If working on weak/friable backgrounds such as cob, please contact us for further application information.

Do not use this product if the temperature is above 30°C, below 5°C or if the risk of frost or snow is present within the next few weeks, this includes temperature drops associated with wind-chill.

‍

‍