External Wall Insulation is an efficient, cost-effective way to improve the energy efficiency of a building while maintaining its aesthetic appeal. However, installing EWI in extreme climates, such as sweltering heat or freezing cold, can pose unique challenges. Here's a step-by-step guide to successfully installing EWI in such conditions.
Choosing the right insulation materials
Selecting the right insulation material is a critical step when installing EWI, especially in extreme climates. In hotter climates, materials with a high R-value (thermal resistance) are ideal as they provide excellent resistance to heat flow. Polystyrene and polyurethane foam, for example, are highly effective at preventing the inward transfer of heat, and keeping interiors cool.
In contrast, in colder climates, insulation materials should have excellent moisture-resistance properties to avoid freezing and associated damage. Mineral wool or expanded polystyrene (EPS) are great choices as they resist moisture absorption and possess good thermal performance, helping to keep the cold out and warmth in.
| Thermal conductivity | R-value | |
| Mineral Wool | 0.036W/(m2K) | 1.39W/(m2K) |
| EPS | 0.032W/(m2K) | 1.97W/(m2K) |
| Kingspan K5 | 0.021W/(m2K) | 2.5W/(m2K) |
Weather conditions and installation timing
Timing your installation to coincide with favourable weather conditions can make a significant difference. In hot, humid climates, the adhesive's efficacy that binds insulation boards to the wall can be compromised. In freezing temperatures, there's a risk of adhesive freezing, which can lead to poor adherence and potential insulation failure.
Therefore, it's crucial to check local weather forecasts and plan for installation on a dry day with moderate temperatures. If such a day isn't forthcoming, you may need to consider weather-resistant materials designed to cope with such conditions or erect a temporary shelter around your work area to protect it from the elements.
Our Render Accelerator is the perfect solution for accelerating drying times; it also speeds up the curing process, allowing for faster job completion.
Preparing the wall surface
Regardless of the climate, the preparation of the wall surface is a key step in the EWI installation process. The wall surface should be clean, dry, and free from any defects, such as cracks or unevenness. Existing paint layers should be removed, and the wall should be repaired and levelled where necessary. The Levelling Mortar is the perfect solution for fixing small surface cracks in the substrate. As a result, you will have a perfectly level surface on which to apply your basecoat or adhesive.
This step becomes even more critical in extreme climates, where temperature and humidity fluctuations can exacerbate any small imperfections, leading to potential insulation failure. Therefore, investing time in thorough wall preparation can ensure more durable and effective insulation.
Installing the insulation
In hot climates, it's advisable to install insulation during the cooler parts of the day, such as early morning or late evening, to minimise exposure to intense heat. In cold climates, avoid installation during sub-zero temperatures to prevent the adhesive from freezing.
Start by applying the adhesive uniformly to the back of the insulation boards, then press them onto the wall. It's important to ensure there are no gaps between the boards. Gaps can create thermal bridges, which are areas of higher thermal conductivity, leading to heat loss and reducing the effectiveness of the insulation.
Applying the render
Once the insulation boards are firmly attached, the next step is to apply a base coat of render. This layer is an additional barrier against the elements, protecting the insulation beneath it. The render should be reinforced with a mesh for additional strength and durability.
In hotter climates, a light-coloured render can help reflect the sun's rays, reducing the amount of heat absorbed by the wall. In colder climates, a darker render can absorb more heat during the day and slowly release it during the night, helping to keep the interior warm.
Protecting the installation
In extreme climates, protecting your EWI installation from the elements during the curing process is vital. In hot climates, consider shading the wall to prevent rapid drying, which can cause cracks. For colder climates, use a protective layer to shield the installation from rain, snow, and freezing temperatures until the render has fully cured.
Regular maintenance
Regular maintenance checks are crucial for the longevity of EWI, especially in extreme climates. These checks should include looking for signs of damage or wear, such as cracks, flaking, or areas where the insulation has become exposed. Any issues should be addressed promptly to prevent further deterioration.
In hot climates, be aware of any signs of heat damage, such as discolouration or warping of the insulation boards. In cold climates, look out for moisture intrusion signs, which could lead to freezing and subsequent damage.
Apart from regular checks, seasonal maintenance checks are also essential. These include checking for damage after a particularly hot summer or cold winter. Extreme weather conditions can cause accelerated wear and tear, and it's crucial to detect and repair any damage early.
Post-installation measures
After successful installation and curing of the EWI, it's essential to install proper drainage measures, especially in colder climates. This prevents any water or moisture from being trapped behind the insulation, which can lead to dampness and mould growth.
In hot climates, consider installing sunshades or other external shading devices to minimise direct sun exposure, which can lead to overheating and damage to the insulation material over time.
Professional assistance
While it's possible to install EWI as a DIY project, getting professional assistance can ensure a successful installation, especially in extreme climates. Professionals have the expertise to choose the right materials, properly prepare the wall, and install the insulation accurately. They can also provide valuable advice on maintaining the EWI and mitigating climate-specific challenges.