How to increase the thermal efficiency of walls and floors in older buildings without adversely affecting moisture levels.
When used as a simple insulating base coat on walls or as a lightweight screed on floors, ProofTherm adds significantly enhanced thermal performance to what are essentially functional elements of a building and provides a simple and affordable insulation upgrade for hard-to-treat properties or areas within a property. This improvement on standard plasters, renders and screeds reduces heat loss through floors and walls and thereby reduces the carbon footprint of older buildings.
ProofTherm uses expanded Perlite as an insulating aggregate. Perlite is a naturally occurring form of volcanic glass that is full of minute air bubbles trapped in a honeycomb-like structure. When incorporated into their bagged, ready to use render, plaster and screed range it is these microscopic air bubbles that create an effective barrier to thermal conductivity.
ProofTherm insulating render has an independently verified thermal conductivity of 0.06w/m2K. When applied as a render basecoat to an external/internal wall it creates a breathable, thermally resistant continuous barrier against heat loss, reducing the heating/cooling load of the building without creating the moisture retention problems so often associated with the regular petrochemical insulating materials.
A 20mm base coat of ProofTherm render to a bare masonry wall can increase its thermal resistance by up to 250%.
The material cost of using ProofTherm insulating render is approximately £6.50 ex vat per m2 when applied at 20mm depth. Heat loss through walls accounts for approximately 35% of all heat loss in the average UK home according to the Energy Savings Trust. Once installed, ProofTherm requires zero maintenance and has a service life in excess of 30 years.
ProofTherm was used to insulate the external walls of a Victorian property in London in October 2020. By February 2021 the owner had measured a 20% reduction in relative humidity in the lower ground floor area as the breathable nature of ProofTherm allowed the bricks to dry out once the existing sand and cement render was removed.
As the lower ground floor area was electrically heated and metered independently from the rest of the property, a recorded reduction in electricity use of 22% across the equivalent period and with the same occupation and usage patterns can be largely attributed to the increased insulation values of the walls.