How to insulate the door of a garage ?

The garage door is a practical or even aesthetic element today, but which, on its own, does not provide the thermal insulation necessary for the garage. However, it is a room that should not be neglected, firstly because it often serves as an airlock between the house and the outside, but also because the garage is increasingly becoming a storage room rather an annex to park a vehicle. It is therefore recommended to insulate it well for optimal comfort.

What types of insulation should you consider?

In order to avoid heat loss, several types of insulation exist. Whether bio-sourced, synthetic or mineral, each carries interesting virtues.

Polyurethane or polystyrene foam sheets

Being part of the category of synthetic polymer insulators, it is actually plastic worked into different forms. It is the most commonly used insulation.


Both polyurethane and polystyrene have notable qualities: economical, perfectly waterproof, weather-resistant, very light, high thermal insulation power. If they both offer similar capacities, polyurethane will remain preferable to polystyrene in terms of efficiency, which will obviously be felt on its price where we will go from simple to triple.


Non-recyclable and made from non-renewable resources, they are not environmentally friendly. In addition, if their thermal insulation capacity is excellent, the sound is much less, which can be problematic depending on the use made of the garage. Finally, these materials are strong combustibles and release harmful gases if ignited.

Wool or wood fiber plates

As we know, wood is one of the best natural insulators, offering a top-of-the-range level of thermal and acoustic performance. The difference between wood wool and wood fiber lies in their manufacturing process.

The wood wool plate is flexible or semi-rigid. It consists of crushed wood fibers, dried, fireproofed, then agglomerated with polyester.

The wood fiber plate is rigid and is obtained by recovering waste from wood processing that is mixed either with water or glue.

These two types of plates are often complementary. For the garage door, we prefer the rigid wood fiber plate, but both can be used. These materials are heavier than plastic-based materials, but more efficient and moisture absorbers which cleans the atmosphere of the garage.

cork sheets

Composed of cork bark residues, this makes it a 100% natural insulator. In addition to its eco-responsible aspect, it has the advantage of excellent thermal and sound insulation. It has the power to retain heat and diffuse it inside.

The thermo-reflective film

It is probably the least effective insulator on the established list. It will be preferred on overhead garage doors that will not support too heavy a load.

And the garage door: insulating material?

These different insulators will be chosen in particular according to the material of your garage door. Indeed, some materials have a natural insulating power while others, conversely, are powerful conductors of temperature.

  • Prison is an extremely conductive material, which makes it almost ineffective in terms of insulation since it will communicate both the extreme cold of winter and the scorching heat of summer. A powerful thermal insulator will therefore be necessary;
  • Wood is an excellent natural insulator. A wooden door will eventually need a simple reinforcement of insulation of the lightest it is, but here it will rather be a question of obstructing the openings between the door and the ground with a weatherstripping;
  • Metal or PVC are the most modern materials found almost systematically on recent constructions. Very often already equipped with insulation, PVC or metal garage doors offer good load resistance, which will allow them to support any type of additional insulation.

Also, depending on whether it is tilting, folding, sectional, swinging or rolling, the choice of insulating material will be constrained by the format of the garage door.

Additional tips

Here are three tips for a perfectly insulated door over time.

Installation of weatherstripping

Still to limit heat loss, it is possible to add a weatherstripping to your garage door that will block the air between the door and its frame. It consists of two parts of plastic or aluminum surrounded by rubber: one under the door to seal the threshold, and the other along the sliding panels to finish insulating it. On recent door models, it is usually included.

The interview

The lifespan of any device or material will depend on the regular cleaning and maintenance given to it. Same principle for the garage door, whose rubber cushions, plastic strips or seals will wear out over time, first by friction of course, but also by bad weather and sunlight and moonlight. . It will be necessary to renew them when a path of air will be felt again.

Call a professional

Most handymen will know how to do it with commercial materials and perhaps the pair of arms of a charitable soul. For the most amateur, it will be better to call on a competent company in terms of energy renovation, ideally an RGE certified craftsman (Recognized Guarantor of the Environment), a guarantee of expertise in the sector.

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