Do you know the “Thermal, Acoustic and Ventilation Regulations” (RTAA DOM)? If you have had your house built in recent years, this acronym must have been introduced to you by the architectural firm you may have hired. Conversely, if you settled for a small construction company, there is a good chance that these regulations will never have reached your ears. We interviewed an architect to ask him why many new buildings end up being fitted with air conditioners.
Zinfos: Why do we continue to see houses built from the ground with air conditioners? Shouldn’t the RTAA DOM modify our approach from the design of the buildings?
An architect : The RTAA DOM, which is part of the construction code, does not require means, it requires results. That is to say, builders are not obliged to use biosourced wood, for example. The RTAA DOM gives as a principle that a minimum of thermal comfort is necessary for housing and that this should not only depend on the choices of the user when they are in the housing. It is implied that you should not depend only on the air conditioning.
When will Reunion Island be able to say that it has passed the milestone of building with passive energy?
Passive energy is another step above. With the RTAA DOM, we are already asking manufacturers not to consume too much energy and to offer thermal comfort. So today the RTAA DOM requires that constructions have natural through ventilation. Reunionese people can notice them around them: buildings in RTAA DOM are new housing which are built in a fairly narrow strip where you most often have one facade with floors and the other a facade with passageways. It is therefore necessary to have windows on both facades to pass air into the home. Then the accommodation must be sufficiently insulated in terms of the walls and the roof. If we don’t insulate, it will be a building that will absorb heat. And it is necessary to protect the openings from the sun so that it does not enter directly into the room. If we already have all this, we have already taken a big step. Afterwards we will add air fans. Be careful, not fans but air mixers!
Then there is what is not regulated but which makes common sense. This concerns the treatment of the surroundings of buildings. I’ll give you an example: if we have natural through ventilation, we don’t treat the gardens at the foot of the building and there are car parks which come right up to the foot of the building, we will bring in hot air inside the accommodation so everything that has been done will have been for nothing! Unfortunately, this exterior part is not regulated because the RTAA DOM governs the building and not the garden part.
The regulations do not say that air conditioning is prohibited but say that air conditioning is only the last resort. That’s simplified but it’s very technical, there is for example a percentage of façade porosity, thickness of insulation, it’s a very technical specification from the RTAA DOM.
Once construction is complete, who is in control?
People often think that it is the town hall but the town hall is only competent for the control of town planning through its PLU but not for the construction code of which the RTAA DOM is a part.
Are these checks carried out?
There is control over collective housing, among developers, SEMs, private companies. They are therefore aimed at project owners who are professionals and not at ordinary people. Each year there are between 15 and 20 constructions which are controlled by the DEAL.
We are clearly sampling!
This is indeed sampling. The problem for the DEAL is that, when they control, they give notice, for example, to the SHLMR, SIDR or CBO to redo what is wrong, but give notice to Mr. or Mrs. Payet to enforce the RTAA DOM for its construction is something else…
The DEAL, when it takes action, it does not backtrack, it goes directly to the judge. So today there is, I would say, a lack of means to force small businesses that make their living from the villa world to control what they do. The only thing we can do, as architects, is to alert the project owners by telling them: “be careful, the RTAA DOM is not an option, it is part of the building code! “.
Do these small construction companies take these environmental standards into account?
I am skeptical of those who really only make individual villas. There are not many who are legal on the RTAA DOM. There are some who understand the general principle.
What is stopping the application of RTAA rules?
We have to put in the resources. It represents an additional cost for individuals to ask a professional to check that their construction tradesman complies with the RTAA DOM, because it cannot be seen with the naked eye. On villas, as the professionals are not controlled, it is very complicated to enforce these regulations. Did the construction company put in the right percentage of insulation? Did they put the insulation in the right color for the roof because depending on the color, it will make the sheet heat up more? In short, as it’s very technical, I’m not sure it’s respected properly. The construction contractor must look for his suppliers, manage his workers, so when he already manages to do all that, he is happy to complete the project successfully, so if he also has to keep up to date with the latest regulations… Entry-level construction companies are not the ones who know their stuff. However, it is not that complicated to do in RTAA DOM, it is much more complicated collectively, it has changed the face of buildings and the habits of architects. And we must say that RTAA DOM is really the basics, we could do much better!
This is how we always end up seeing houses or apartments that end up being equipped with air conditioners?
Not all users are ready to test whether, without air conditioners, they will be in thermal comfort. They are already used to air conditioning where they were, so they arrive with this requirement for air conditioning when they consider their house project.
However, even if we cannot compare through ventilation with air conditioning, we can live with through ventilation 95% of the time in Reunion. There will remain 5% of the time where we will be uncomfortable, we will be really very hot. Perhaps we need to know how to accept these 5%.
Why are there no controls on the constructions of ordinary people?
In fact, it’s a bit of the other side of the coin. As the architect is not obligatory for constructions below 150 m2, well there is no control! On the other hand, from the moment there is the architect, there are construction rules, there are insurances which come into play and therefore control obligations.
On which document does an individual or developer declare that their construction has complied with RTAA standards?
The law considers this to be self-evident. On the last page of the Cerfa of its application for authorization for a building permit, just below where the owner puts his name, the date, declares on his honor and signs, it is marked in very small letters “ I undertake to respect the construction code”.
In mainland France it goes a little further than that since you need a design office certificate. In the French Overseas Territories there is no such requirement. That would be a good start. This would be a good way to control and support users.
In 2024, we are therefore unable to say how many new constructions have been built while respecting the standards of the RTAA DOM of 2010 revised in 2016?
Indeed because there are no controls.
That’s crazy !
It’s crazy but the power is in the hands of the project owners, that is to say the owner who orders his house. Only he can require his construction company to comply with the RTAA. But most of the time, the owner has other priorities to deal with: he is trying to obtain his bank loan, find a company that fits his budget, in short he no longer knows where to turn! So there you have it, the only avenue for me which would be interesting, even if it would fall on the owner, would be to integrate into the building permit the same requirement as there is in mainland France, that is to say to have the proof that the project complies with the RTAA DOM at the time of the permit. It would be necessary to have someone outside who would control the file. So that would be an additional cost for the project owner.
Contacted, the prefecture gave us the response from the Department of the Environment, Planning and Housing (DEAL) to our question relating to the non-existence of controls for private homes:
DEAL: “It is primarily the responsibility of the project owner of an operation to ensure that their project complies with the RTAA-DOM and to be supported by competent design offices in this area.
The DEAL then carries out the mission of controlling construction rules which consists of verifying that the construction carried out complies with the rules relating to safety, fire, accessibility and the RTAA-DOM and, where applicable, in the event of identified non-compliance with one or more of these regulations; to report it to the judge.
In 2024, 12 housing operations will be controlled by the 2 sworn inspectors of the DEAL. »
