Today is the first day of winter 2021, an ideal date to talk about thermal insulation and thermal comfort. Indeed; following the recent sharp increases in energy prices, isolate his house is more than ever an efficient solution for saving money and preserving the environment and resources. There are several solutions for this and it can sometimes be complicated to find your way around. This article gives you the opportunity to take stock in 2021 on the different insulation techniques and to learn more about insulation. More particularly insulation from the outside!
What are the different types of insulation possible?
When it comes to insulation, there is no one-size-fits-all solution for every situation. It is therefore important to start by remembering that the ideal solution may not be the same for your home as it is for another.
We generally consider two main types of thermal insulation:
- Thermal insulation from the inside or ITI
- Thermal insulation from the outside or ITE
To this we must add roof insulation which is also important whatever the solution chosen for the insulation of the walls.
For the insulation to be successful, there are several criteria to take into account. The constraints will not be the same in a building under construction as in a habitat that you occupy during the work. Not all types of insulation will fit into the same budget. And it is very likely that you will have to make concessions between aesthetics and efficiency !!
So how do you choose between insulation from the inside or the outside?
While every situation is different, there are a few general criteria that can help you make your choice. So if you already occupy your house, it is likely that you will see as a major constraint the fact of having to remove plasterboard and other plasters to re-insulate your house from the inside. The exterior insulation will then have the advantage of being able to be carried out without touching your existing decoration, and without hazards for the occupants of the house since everything takes place outside! Conversely, if you have a house whose facade is an asset (stone facades for example), insulation from the inside could allow you to keep the original character of your house.
If, however, you do not have a preference between exterior or interior work (which is frequent in the case of new construction to be insulated during the work) other criteria must also be taken into account. Interior insulation remains the most common, so that for which it will be easier to find a contractor able to carry it out, it is also generally less expensive than insulation from the outside.
However, by opting for this solution you would risk depriving yourself of significant advantages such as saving space (insulating from the outside optimizes the space available in the house since such a solution is built without encroaching on the m² of living space). On the other hand, the ITE often presents a better compromise to avoid thermal bridges, that is to say the places of your house more vulnerable to humidity and heat loss. By insulating from the outside, it is often the entire facade that is covered with an insulating material !!
To discover in detail the advantages and disadvantages of each of these two solutions, we invite you to watch this particularly comprehensive video on the subject.
What materials to use?
The materials used for the insulation of houses can be grouped into four main large "families". We will set aside for this article materials from the petro-chemical industry. Although these are the most commonly used, these materials are not environmentally friendly or are responsible for havoc on the environment.
We will also discard reflective materials, says thin insulators (which are only really effective in space), to focus mainly on the main families of insulation that interest us: insulators of plant origin and those of mineral origin !!
On the side of insulating of mineral origin we find in particular different wools. Although these materials are less ecological than those of natural origin, we find in this family of insulators which can be particularly interesting. This is for example the case of rock wool which has many advantages !! Of natural origin, it is obtained from basalt: a rock of volcanic origin available in satisfactory quantities. This wool can insulate both walls and floors (which gives it an additional advantage over its cousin, the well-known glass wool which only allows wall insulation). It can also have a relative effectiveness on the insulation against the heat in the summer, although not being the most effective at this level. In the event of a fire, rock wool is considered to be not very flammable and likely to slow down the progression of the flames. Its combustion does not release toxic fumes. It is also resistant to water, which is very interesting to avoid possible humidity problems. Finally, in general, insulation materials of mineral origin have a good quality / price ratio.
However, wools are mainly suitable for interior insulation of houses. External insulation will often make it possible to call on the family of materials of natural origin. Here we can cite fiber panels cork or wood, bricks, for example hemp brick, or simply straw. These materials come from a more easily renewable production and tend to involve less energy expenditure during their manufacture. There are also natural wools, such as wood wool, hemp, or even cotton. These wools make it possible to complete an ITE or to carry out an ITI while respecting the environment.
In this video, you will find an example of the use of straw for exterior insulation:
What are the pitfalls to avoid ?
When choosing the type of insulation for your home, several pitfalls can stand in your way !! Thus, when insulating from the outside, it is important to check with the land registry that your house is eligible for this type of insulation. Indeed, if the insulation is not carried out at the time of the construction of the habitat, it will be necessary to verify that the building area available around your house is sufficient to achieve it.
If you live in an area classified as a historic monument, you may also not be allowed certain exterior insulation techniques. See that your facade cannot be changed at all.
In general, it is important to identify the areas at risk of thermal bridges in your house, and to compare their extent with the different insulation techniques considered. You will then probably have to make a compromise between budget and aesthetics, while trying to optimize these thermal bridges as much as possible so that they are as few as possible!
Finally, if your more or less long-term goal is to sell your house through an agency, consideration should be given to the choice of materials used. Indeed, the importance given by the agency to the insulation technique used will in many cases be relatively low. So effective insulation but too expensive in terms of materials could lead to a loss of money when you put your property up for sale. However, this concern can easily be circumvented by offering your purchase for direct sale, more and more buyers being sensitive to the ecological nature and respectful of the health of their future habitat.
The roof, an essential insulation!
For successful insulation, there should only be as small an area as possible of your home that is not covered with an insulating material. In these conditions, insulate the roof and the attic which represent an important part of the home is an essential task for the good conservation of heat by your home.
Wool, whether mineral or natural, is particularly suitable for this type of insulation. If you want to inhabit the space in contact with your roof, you can also use insulating panels which will complete the wool previously laid.
However, you may not want to insulate your roof from the inside either. In the event of a total renovation of the latter, or in the event of a new construction, it is possible to carry out insulation from the outside as well. Two methods are then possible: in the first, the insulation will be interposed between the rafters that make up the roof of your house. A second method called sarking, will allow the insulation of the roof by positioning the material chosen above the rafters. The second solution being more effective in order to avoid thermal bridges, but also more complicated to set up. For the insulation of the roof from the outside, it will again be possible to use various insulation materials. Straw is an interesting possibility that can also be adapted to this type of situation.
To conclude on insulation from the outside
As you can see, insulating your home requires making several relatively important choices. It is therefore recommended to call on one or more expert opinions if you do not already have a solid knowledge of the subject.
By finding the right compromise, and using the right materials, insulation properly done should allow you to save energy, while making your home more comfortable. These energy savings can only be beneficial for the environment, especially if your choice of materials has turned towards natural alternatives to the most famous insulators.