Internal ceiling insulation: complete guide and help

The ceiling, often underestimated, plays an essential role in the thermal performance of a home. The heat escapes from the top first.especially in old or poorly insulated houses. Insulating it from the inside not only allows it reduce energy lossesbut also to avoid drafts, noise pollution and sensations of cold. Let’s see together how to proceed correctly for a long-lasting and comfortable result.

Why is ceiling insulation essential?

In a poorly insulated house, up to 30% of the heat can escape through the ceiling. The cause: warm, lighter air, which naturally rises and accumulates under the roof. This heat loss leads to excessive heating consumption and a high bill at the end of the month. Insulating the ceiling therefore becomes a priority.

But that’s not all: good insulation also limits noise pollution, which is very appreciable in a building or a two-story house. Finally, it contributes to energy efficiency housing, an essential criterion of current environmental standards such as RE2020.

Which insulation to choose for a high-performance ceiling?

There are three main families of ceiling insulation:

• Mineral insulators : glass wool, rock wool
• Natural insulators : cellulose wadding, wood fibre, cork
• Synthetic insulation : polystyrene, polyurethane (PUR)

To choose wisely you need to know two fundamental facts:

• THE lambda (λ)which measures thermal conductivity: the lower it is, the better.
• THE thermal resistance (R)which reflects the ability to block cold or heat: the higher it is, the more effective the insulation is.

THE polyurethane it is very efficient thermally but poorly insulating phonetically. Glass or rock woolfor their part, they offer a good compromise between thermal and acoustic insulation. THE expanded corkeco-friendly and sustainable, it is also a great option for nature lovers.

How thick should you plan to insulate a ceiling?

The thickness of the insulation depends above all on its type and the space available. On average, we recommend between 12 and 30 cm of insulationdepending on the material chosen and the desired performance.

In a home where the ceiling height is generous, it may be wise to install a drop ceiling to accommodate a thicker layer of insulation. This heat gain is immediate. In addition, reducing the ceiling height makes it possible heat a smaller volumethus realizing further savings.

What techniques to insulate a ceiling from the inside?

Two main scenarios:

• The flat ceilingbetween two floors
• The creeping ceilingunder roof

For a straight ceiling, the most common method remains the same installation of a suspended ceiling. It consists of fixing metal or wooden tracks to the existing ceiling between which the insulation is inserted. Everything is covered with plasterboard, wooden paneling or decorative panels.

If the height is low, we will rather opt for a stretch ceiling OR thin insulation glued directly on the plate. This technique makes it possible maintain maximum height while providing a minimum of insulation. On the other hand, thermal performance is more limited.

Should we hire a professional for this job?

It is quite possible to insulate a ceiling yourself, especially by opting for semi-rigid panels OR easy to install rollers. However, a specialized craftsman guarantees professional installation, without thermal bridges, and will be able to advise you choosing the most suitable materials for your home.

Another interest: an RGE (Recognized Environmental Guarantor) professional allows you to do so benefit from state aidto the conditions. It also has ten-year insurance, a guarantee of peace of mind in case of future problems.

What aids are available for ceiling insulation?

Good news: various aids can finance all or part of the insulation work of your ceiling.

• MaPrimeRenov’ : open to all families, its amount varies depending on income.
• MaPrimeRénov’ Serenity : up to 50% of the work if the energy performance is improved by at least 35%.
• Energy Saving Certificates (EEC) : paid by energy suppliers.
• VAT reduced to 5.5% on materials and labor.
• Zero interest eco-loan (Eco-PTZ) : up to €50,000 repayable without interest.
• Local help : often little known, they integrate national systems.

To benefit from this it is necessary that the works are carried out by an RGE certified company. Remember to check the conditions before starting!

Insulating a ceiling from the inside is much more than a project: it is a step towards a healthier, quieter and above all more economical home. An intelligent investment, which combines daily comfort and enhancement of your property.