What is The Best Exterior Insulation?

What is the best exterior insulation: The best thermal insulation from the outside is achieved using rock wool. Even with a thin thickness, this mineral material is associated with formidable thermal performance. In the context of ITE, the insulation and moisture resistance capacity of this mineral wool is essential.

In this article, we invite you to discover the different solutions for external wall insulation and the best insulating materials to use. Whether it is insulating the roof or the walls of a house, there are different methods.

The following paragraphs will undoubtedly allow you to find the one that corresponds to your renovation project.

Table of Contents

What are the exterior insulation methods?

Thermal insulation of walls

Four common solutions are allowing exterior insulation of the walls of the home. You can choose between:
  • The use of hard insulating panels which are fixed to the wall by gluing or screwing, which are then covered with coating. It is important to specify that this technique should only be used for exterior walls that do not show irregularities or traces of humidity.
  • Insulation is protected by a frame, allowing insulating panels to be fixed, ensuring air circulation between the insulation and the cladding. This technique is ideal for irregular, cracked, and damp facades.
  • Under-cladding insulation, which consists of facings installed directly against the walls.
  • The facade coating is applied to the existing facade.

The first method mentioned has some advantages. In addition to the ease and speed of breaking the panels, it allows you to benefit from optimal insulation. It will also involve modernizing the facade if it needs a refresh. [What is the best exterior insulation]

Read also: What Insulation Between Two Common Walls?

Thermal insulation of the roof

Roof insulation does not necessarily have to be done through the attic. It is possible to use a method called sarking. This is the best solution for external thermal insulation, to reduce losses at roof level without losing habitable volume.

The steps to achieve it are as follows:

  • Install the vapor barrier on a deck to ensure airtightness
  • Install the insulation
  • Install the lathing and the counter lathing using a screw system provided for this purpose
  • Replace the usual roof covering

What materials to choose for the exterior insulation of a house?

Finding the right materials for the exterior insulation of a house is also at the heart of a renovation process to optimize energy performance. You will have the possibility to choose between:

  • Mineral wools, such as glass wool or rock wool, are the merits of which we have already praised with their ideal properties against heat loss and humidity.
  • Natural insulators, such as cellulose wadding, sheep wool, or even wood fiber. Renowned for their durability, they allow exterior insulation to be carried out in line with the ecological beliefs that may be yours.
  • Synthetic insulators, developed specifically to withstand all climatic conditions, offer optimal insulation. You can notably focus on propylene, polystyrene, or even resold foam.

To give you a better idea of ​​the materials to choose depending on your construction or renovation work, you should know that rock wool, glass wool, or even polystyrene are recommended for insulation under exterior coating.  

Read also: How to Insulate a Cold Wall From The Inside?

When it comes to wall insulation from the inside, cellulose wadding and polyurethane are the materials of choice for sprayed insulation. [What is the best exterior insulation]

Should we insulate the attic or the walls?

You may be wondering which method is more effective: roof or wall insulation. It is important to understand that only a specialist carrying out an energy performance diagnosis specific to your home will be able to answer you.

For example, you can rely on a DPE carried out with a diagnostician. Since 2021, this document is no longer based on the analysis of invoices at all. It is designed thanks to a real investigation by professionals, to help identify the strong points and weak points of a home.

You will be able to find out if the heat loss or humidity comes from the attic or from poor wall insulation. It’s then up to you to achieve the best insulation from the outside.

What materials should you choose for the best exterior insulation?

In the context of exterior insulation, rock wool is often preferred. With a thermal conductivity of 0.045 W/(mk) and 0.034 W/(mk), it is also the most economical. As a more natural alternative, it is possible to rely on cork or even wood fiber.

The climatic characteristics of your region can also guide your choice. In a very humid and rainy area, it is possible to rely on synthetic materials such as polystyrene or polyurethane which provide ideal waterproofing.

Why insulate exterior walls?

First of all, it is important to remember that the insulation of exterior walls has been mandatory for all roof repair, development, and facade renovation work since January 1, 2017.

In addition, insulating the exterior walls of your home has several advantages in terms of heat loss, living comfort, and energy savings. [What is the best exterior insulation]

Limit heat loss

Well-insulated exterior walls limit heat loss by avoiding thermal bridges. Moreover, these losses do not only concern heat in winter. Indeed, insulating materials also help maintain freshness in summer in addition to heat in winter.

In addition, you should know that the exterior walls of the north and west facades are the most sensitive in your home. Not being exposed to the sun, these walls are less resistant to cold and humidity. Condensation may then form on the walls if they are not insulated.

Improve comfort from a thermal and sound point of view

Whether for the insulation of attics, low floors, or exterior walls, living comfort is always improved. Indeed, the occupants of the accommodation then benefit from a pleasant environment to live in, both summer and winter.

From a thermal point of view, the insulation of exterior walls greatly contributes to keeping the heat or coolness depending on the season. It is also important to point out that a good insulating material offers excellent sound qualities to isolate itself from external noise.

Make energy savings

Insulating materials for exterior walls help limit heat loss and thus save energy. You must increase the heating power in your home if heat loss is too high. In addition, the amount of energy savings achieved is always reflected in the amount of your heating bill.

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