External Thermal Upgrade Leads To Integrated Savings

Solid wall homes will lose as much as 45% space heat through untreated walls and unfilled cavity wall homes lose approximately 35% of heat through their walls. Any measures to make heating more efficient are made less effective as heat escapes through the external walls. Increasing the thermal insulation of both existing and new buildings can be effectively achieved by the addition of external thermal insulation. External thermal upgrade insulation systems are a means of applying layers to the outside of a building with the primary aim of improving thermal performance. Overall benefits include: • a reduction in heating, air conditioning and overall running costs • increased internal comfort • a reduction in condensation where this has been present • improved weather resistance • better external appearance when added to an existing building • no internal disruption to the structure or its inhabitants External thermal insulation systems can be used on existing solid-walled construction and cavity walls even if these are partly or completely filled with insulation. The majority of systems feature: • an insulating layer – expanded or extruded polystyrene, polyurethane, phenolic, isocyanurate or other lightweight material. This requires a fixing system to hold it to the masonry background and this could be an adhesive, physical connectors or a combination of both. • a reinforcing layer – to protect insulating layer against impact in the form of metal or plastic mesh. • a finishing layer – specialist render finish to provide weather proofing and decoration and sometimes additional impact or abrasion resistance. This should be resistant against water penetration but moisture permeable to allow vapour in the structure to be released externally. Specialist renders required must be able to resist thermal shock, adhere to the special backgrounds used and have an acceptable impact resistance. They usually contain relatively large amounts of polymeric materials. Renders may contain a lightweight mineral aggregate such as perlite, vermiculite, expanded/ sintered clay or an organic product such as expanded polystyrene. Both wet-dashed and dry-dashed renders are used, although in general, the render coats used contain smaller-sized aggregates than would be the case with such materials. ENERGY SAVINGS Addition of insulation to the external wall of a structure can make a significant contribution to reducing the amount of energy needed for heating. Good thermal values are built into the design of new structures, but the UK and Ireland has a considerable stock of existing buildings without effective insulation. Air conditioning also requires additional energy. Increased levels of insulation are essential to reduce further energy costs and the emissions of carbon dioxide. IMPROVED COMFORT Reducing energy consumption enables the heating of a structure while still reducing energy input. External insulation also means that the main mass of a building – generally brick and block masonry – will absorb heat at its working temperature, effectively acting as a heat store. When heating is switched off, the temperature will not drop suddenly because the main fabric of the building acts as storage heater, emitting the heat back into the interior of the building. Without rapid heat loss and cycles of heating and cooling, occupants experience a more comfortable environment. External thermal insulation systems eliminate cold bridging which is caused when an element of a structure conducts heat continuously from the outer face to the interior. External thermal insulation systems overcome these problems by assisting to keep the desired temperatures within the buildings. CONDENSATION REDUCTION Condensation occurs when water vapour produced in a structure condenses on a surface at or below a critical temperature, known as the dew point. The naturally occurring levels of humidity within a building and cold bridging will bring about condensation – again an occurrence remedied by external insulation. AESTHETIC APPEAL External thermal insulation systems can play an important role in improving the external appearance of buildings of all kinds and ages. Its use will not only upgrade thermal and related issues but through careful choice of the finishing layer will successfully refresh the external facade of a structure. WEATHER PROOFING AND GENERAL REPAIR Application of external thermal insulation systems provides a weatherproofed structure, overcoming difficult or complex problems of water ingress that may be too expensive to repair in isolation. INTERNAL SPACE SAVING One option for upgrading a building’s thermal performance is to place an insulated board on internal walls. Not only does this fail to capitalise on the thermal mass of a structure, it also impinges on the internal dimensions. Additionally, the fixing of internal insulation can be difficult because of the location of elements such as kitchen units, baths, basins, electric sockets, cornicing and so on, yet still enabling cold bridging in certain circumstances. External thermal insulation systems encompass the whole heated living space and the structure. TECHNICAL REQUIREMENTS Care must be taken in designing the application of external thermal insulation systems around window reveals, sills and returns. There may be a need to extend and improve these elements and this should be considered in detail at the preliminary design stage. External thermal insulation systems should be regarded as an integrated system, not a selection of components – with their own separate needs – that can be brought together to form the complete job. For further information, contact Stephen Dickson on 028 4275 8097, email dicksonarchitects17@tiscali.co.uk or visit www.dicksonarchitecturalservices.co.uk