If your home was built before 1920, it’s likely that you have solid external walls rather than cavity walls. Unlike modern homes with cavities that can be filled with insulation, older solid-wall properties require a different approach to improving energy efficiency. This is where External Wall Insulation (EWI) comes in—a highly effective way to keep your home warm, reduce heat loss, and improve comfort all year round.
1. What Is External Wall Insulation?
External Wall Insulation is a layer of insulating material applied to the outside of a property. It’s then covered with a protective render or cladding to create a durable and weather-resistant finish.
This method of insulation is particularly beneficial for homes with solid brick, stone, or concrete walls, where internal insulation may not be practical. Instead of insulating from the inside and reducing room space, EWI enhances the thermal efficiency of the property from the outside without disrupting your living space.
2. How Can You Tell If Your Home Has Solid Walls?
If your home was built before 1920, it likely has solid walls, but there are a few ways to check:
✅ Brick Pattern: Solid brick walls typically have an alternating brick pattern, whereas cavity walls have uniform, evenly spaced bricks.
✅ Wall Thickness: Measure the thickness of your external walls at a door or window. Solid walls are usually less than 260mm thick, while cavity walls are thicker.
✅ Construction Style: Many period homes (Victorian, Edwardian, and Georgian) were built with solid walls, particularly in cities and older towns.
If you’re unsure, a professional insulation assessment can confirm your wall type and the best insulation solution.
3. The Benefits of External Wall Insulation
Installing External Wall Insulation comes with multiple advantages for older homes:
✔ Reduced Heat Loss & Improved Comfort
Solid walls allow twice as much heat to escape compared to cavity walls. By adding insulation externally, your home retains warmth more effectively, creating a cosier and more stable indoor temperature.
✔ No Loss of Internal Space
Unlike internal insulation, which reduces room size, EWI preserves your living space by insulating from the outside. This means no disruption to your interior walls, fittings, or decorative features.
✔ Enhanced Weather Protection
External Wall Insulation also acts as a protective shield against the elements. It helps prevent damp penetration, reduces draughts, and improves the durability of your home’s exterior.
✔ Aesthetic Improvement & Modernisation
EWI refreshes the look of your property by providing a new external finish. Whether you prefer a smooth render, textured effect, or brick-style cladding, insulation can enhance your home’s kerb appeal while improving its thermal performance.
✔ Helps Prevent Condensation & Damp
Solid walls can be prone to cold spots and condensation, leading to damp and mould issues. External insulation creates a thermal barrier that helps regulate wall temperature and reduces the risk of condensation forming inside your home.
4. Can You Install External Wall Insulation on Any Property?
While External Wall Insulation is perfect for older solid-wall homes, there are a few factors to consider:
✅ Planning Permission – Most EWI projects don’t require planning permission, but if your home is in a conservation area or is listed, you may need approval.
✅ Building Condition – Your walls should be structurally sound before insulation is applied. Any existing damp issues should be addressed first.
✅ Property Type – EWI is commonly used on detached, semi-detached, and terraced houses, but for mid-terraces, party wall considerations may be required.
5. External Wall Insulation vs. Internal Wall Insulation: Which Is Better?
Both External Wall Insulation and Internal Wall Insulation have their benefits, but for solid-wall homes, EWI is often the better choice.
| Feature | External Wall Insulation (EWI) | Internal Wall Insulation (IWI) |
| Saves internal space? | ✅ Yes | ❌ No – reduces room size |
| Disrupts home interior? | ✅ No | ❌ Yes – requires redecorating |
| Improves exterior appearance? | ✅ Yes | ❌ No |
| Enhances weatherproofing? | ✅ Yes | ❌ No |
| Helps prevent damp & condensation? | ✅ Yes | ⚠️ Can increase condensation risk if not done correctly |
If maintaining room space and minimising disruption is a priority, External Wall Insulation is the better option for many homeowners.
6. How Long Does External Wall Insulation Last?
When installed correctly, External Wall Insulation is a long-term solution that can last 25+ years with minimal maintenance. High-quality materials and weather-resistant finishes help ensure durability and long-lasting performance.
To maximise its lifespan:
✅ Choose a high-quality insulation system suited to your home.
✅ Ensure proper installation by experienced professionals.
✅ Keep up with minor maintenance, such as cleaning the render or checking for small cracks.
7. Can External Wall Insulation Change the Look of Your Home?
One of the biggest advantages of External Wall Insulation is the opportunity to improve your home’s appearance. Homeowners can choose from different finishes, including:
🎨 Smooth or textured render – A modern, sleek look.
🧱 Brick-effect cladding – Retains a traditional brick appearance.
🌿 Coloured finishes – A chance to refresh and customise the exterior.
For period properties, traditional-looking finishes can be selected to maintain the original character while upgrading energy efficiency.
Final Thoughts: Is External Wall Insulation Right for You?
If your home has solid walls, External Wall Insulation is one of the best ways to improve warmth, comfort, and weather protection while also enhancing your property’s appearance. With long-lasting benefits and minimal disruption to your home, it’s an excellent investment for homeowners looking to upgrade their insulation.
Thinking about External Wall Insulation for your home? Get in touch today to find out how we can help you improve your home’s energy efficiency and comfort.
