We recently completed this External Wall Insulation project at Haven Avenue Brough. Working directly for the Homeowner we installed this energy saving system after discussions with the homeowner whom selected this contemporary grey coloured render.
What is External Wall Insulation?
External Wall Insulation or EWI is a method of wrapping the entire outside of the buildings walls with insulation.
Imagine a tea cosy sliding over a teapot or a giant blanket for your house.
There are several different insulation materials available which are used by all manufacturers, the market leading insulation is enhanced polystyrene slabs or blocks as they are durable, robust and are not susceptible to cracking or taking on moisture.
The exact type of insulation required for a project varies from project to project and your property will first require a survey to determine the best product available for your properties specific needs, although it is reasonable to assume that EPS would be suitable.
Before considering EWI there are a couple of other energy efficiency measures you should consider first, is the loft space insulated? One of the main sources of heat loss in a building is through the roof after all heat rises so first ensure your loft is adequately insulated which means having as many layers of good quality mineral wool as possible. Secondly is glazing and doors, most properties now have double glazing fitted although there may be a few single glazed properties out there it would be worth fitting double glazing before EWI as heat will escape through single glazed draughty window and door installations.
If these two building fabrics are have bases covered and you know are insulated the next step is considering EWI. Over the last 20 years or so the vast majority of buildings have had lofts insulated and double glazing fitted with incentive schemes available recently the government has put in millions of pounds into improving the thermal efficiency of existing building stock. New build properties are been build better and better and insulation, thermal efficiency and human comfort are taking the driving seat in considerations for design and building performance yet there are millions of existing properties that are beautiful and that make up our British culture. EWI & IWI is part of the big answer on improving existing building stock.
What is Internal Wall Insulation?
Internal Wall Insulation IWI is the method of improving the heat efficiency or insulation performance of existing buildings walls by the introduction of Insulation and plaster finish to the inner face of external walls of a property. EWI is generally preferred over IWI as IWI is by no means as efficient and effective as EWI due to creating thermal bridges which can’t easily be insulated at intermediate floors and internal partitions. Also IWI requires working within the property which isn’t a problem if carried out as part of a full re-fit or refurbishment but is not great if the property is nicely decorated, lived in or doesn’t require decoration as re-decoration internally will inevitably be required.
Back to EWI, how is EWI finished?
The insulation slabs (as mentioned above usually EPS) are fixed to manufacturers details in a brick bond pattern to the existing outer walls. The slabs are usually mechanically fixed which required drilling and plugging with bespoke system designed thermal fixings or alternatively the insulation can be adhesive fixed. The EWI has particular details at the base, window and door abutments and external corners which differ from system to system. Once the insulation is fixed a further rasping down of the insulation is required to prepare the system for render. The render is generally applied in a 6mm mesh reinforced coat comprising of a polymer modified cementitious base coat which in layman’s terms is a flexible render which doesn’t crack! This is ideal for EWI, the system is thin flexible and light weight. The base coat is applied using beads all as per system design and once dry is then ready for the topcoat. Flexible renders are specified generally with silicone or acrylic topcoats which are available in a vast array of coloured and textures. The most selected texture been a very smooth 1.5mm grain, colours obviously vary subject to clients tastes. The topcoat is applied after priming the render base coat which all sounds simple enough! But the truth is the application is all down to time served skill, familiarity of working with the materials and the tools ie been applied by a tradesman, by approved system installers, by a specialist. Other topcoats are available such as flexible through coloured renders, pebble dash, brick slips and brick effect render which we install expertly subject to your needs.
All systems that we use here at Hodgson Rendering Specialists are always BBA or ESA approved ie they are fully tested and are suitable for building control, and offer a minimum 10 year warranty which at your request and for a small fee can be increased to an insurance backed warranty.