While the climate in Spain is generally warm, it does not always mean comfortable. Thin walls, poorly insulated facades and poorly built houses can be a source of major discomfort in July and even January. If your electricity bills or your personal comfort is negatively affected by such conditions, one of the best ways to improve the situation is external wall insulation.
Below we explain what it is, what advantages it brings, what to consider when planning such works, and how to choose the right system.
What Is External Wall Insulation?
External wall insulation refers to a set of works on the building’s walls, involving the insulation board installation on the walls’ surface and rendering or other protective and decorative finishing works on top of it. In Spain, this type of work is often called SATE – Sistema de Aislamiento Térmico por el Exterior. An external thermal insulation system usually consists of:
- A fixing profile or adhesive and mechanical fixing elements;
- Insulation boards – most commonly made of expanded polystyrene, mineral wool, or other materials;
- A reinforcing layer – most often a base coat with glass fiber;
- A render – a protective, decorative, and weather-resistant layer.
The insulation layer covers the walls from the outside, thus forming a closed thermal barrier.
Why Insulate From the Outside?
There are several reasons why insulation works should be done from the outside instead of the inside.
It Reduces Thermal Bridges
The points through which heat enters or escapes from a building are called thermal bridges. They are formed unevenly: for example, on the edges of the building slab, or near the pillars and other elements. By insulating the walls from the outside, it is possible to eliminate them almost completely.
It Keeps Your Living Space Intact
By contrast, insulation from the inside requires considerable space. Moreover, arranging such works is quite problematic in occupied housing. At the same time, external insulation minimizes the impact on the interior: fittings, finishes, and other elements can be left untouched.
It Protects the Structure
By insulating the walls from the outside, they are thermally isolated, which reduces the temperature difference and mechanical stress on the wall structure. The external render also serves as a protective layer, preventing the facade from deteriorating.
Benefits of External Wall Insulation in Spain
Comfort All Year Round
In Spain, the climate varies from temperate to subtropical, with long, hot summers and relatively mild, rainy winters. A good insulation system helps to maintain a comfortable temperature inside the house both in summer and winter, reducing overheating and retaining heat.
Lower Energy Demand
By reducing the amount of heat entering or exiting the building, insulation allows air conditioning and heating systems to operate more efficiently, reducing energy consumption. The cost depends on many factors: the geometry and materials of the building, the location, and the size of the building, as well as how intensively it is used. It is therefore unwise to promise a specific efficiency gain in advance. But in most cases, insulation reduces the costs associated with maintaining the desired indoor temperature.
Better Energy Rating and Property Value
Energy performance is now a much-discussed topic in Spain, as it directly affects the ability to rent or sell a property. Almost all real estate in Spain now has an energy performance certificate (certificado energético). Upgrading the insulation is an excellent way to increase the value of a building while reducing its operating costs.
A Fresh Facade
As mentioned above, when insulating walls from the outside, a new render is applied on top of the insulation layer. This allows the facade to be renewed and upgraded to a more efficient one at the same time.
What to Check Before You Start
Proper preparation helps to avoid future problems. When planning external insulation works, pay attention to the following details.
The Condition of Your Walls
Beforehand, it is necessary to inspect the walls’ condition and, if necessary, repair damaged plaster, cracks, and other defects. If the walls are damp, it is necessary to eliminate the source of condensation.
Regulations and Permits
Beforehand, it is necessary to familiarize yourself with the building codes and regulations applicable to your building. In most cases, works on the insulation of facades require a construction permit, which must be obtained from the local authorities (ayuntamiento). In addition, if the building is located in a conservation area or is of particular architectural significance, special permits may be required. In addition, the CTE (Construction Technical Code) sets out standards for the building’s energy performance; the competent authority will clarify what requirements for insulation must be met.
Community Approval
When it comes to multi-family buildings, it is essential to understand that facades belong to all owners. Accordingly, to arrange for their renovation, it is necessary to obtain the consent of the community of owners and, possibly, find an agreement on the division of costs. It is also worth contacting the management company (if any) to clarify the procedures for applying for permission to hold insulation works.
Funding and Incentives
Spain has programs for subsidizing energy saving and renovation works, including insulation systems. Such benefits usually come with specific requirements, so it is essential to study the conditions offered in your region. Besides, it is worth considering whether you will be able to use the superbonus for renovations, deducting some of the costs from taxes.
How to Choose a System and an Installer
Not every project needs the same approach. Here’s what to weigh up.
Match the Insulation to the Building
Various materials are used for external insulation: each has its advantages and disadvantages in terms of thermal performance, fire resistance, and ease of installation. In addition, the choice of material is affected by the geometry of the building, its height, the current climate, and the insulation needs. It is always a good idea to consult with a professional who can advise you on the best solution for your building.
Look at the Whole System
The choice of an insulation system should be comprehensive: it is essential to consider not only the board itself but also the adhesive, profiles, render, and other accessories. This will allow the insulator to select the complete set of materials that will provide the best performance. It is unwise to choose the profile, boards, adhesive, and render separately, as they may not be compatible with each other.
Check Experience and References
It is vital to choose a reliable company with experience in insulation works. It is also essential to study references and ask for information about the qualifications of the team that will perform the works. Particular attention should be paid to the quality of insulation around windows and other weak points in the building. In addition, it is always a good idea to ask for a detailed estimate for the works.
Ask for a Clear Quote
A good quote lists materials, thickness, surface preparation, scaffolding, finishes and timelines. If something is vague, ask.
How Long Does Installation Take?
The duration of insulation works is a factor that should be considered when planning this type of renovation. The time required for insulation depends on the size and complexity of the building, as well as the weather. A small private house will take much less time than a high-rise building. It is worth asking the specialist for an approximate estimate.
Get Expert Advice on Your Project
If you’re considering insulating your property, it helps to talk to specialists who can look at your facade and recommend a suitable system. You can learn more about options on the Ever-Coat thermal insulation page and get in touch to discuss your project.
Frequently Asked Questions
What is external wall insulation?
External wall insulation refers to a set of works on the building’s walls, involving the insulation board installation on the walls’ surface and rendering or other protective and decorative finishing works on top of it.
Is external wall insulation worth it in Spain?
It is definitely worth considering, since it will allow you to improve the microclimate in the house in both summer and winter, and reduce the costs of air conditioning and heating.
Do I need planning permission for external wall insulation?
Usually, it is necessary to apply for a construction permit with the local authorities, since works on the insulation of facades fall under the category of capital construction works. In addition, if the building is located in a conserved area or on the territory of a specially protected area, special permissions may be required.
Can I insulate just one apartment’s facade?
If the building’s facade is shared, you cannot insulate only your apartment: it is necessary to contact the management company and the community of owners to determine who can do this and how the costs will be distributed.
What materials are used for external wall insulation?
The insulation board can be made of mineral wool, expanded polystyrene, or other materials. On top of the board, a reinforcement layer is applied, followed by a special render.