How to Insulate a Concrete Garage Floor

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If you’re looking to transform your cold and uninviting concrete garage into a more comfortable and usable space, insulating the concrete floor is an essential step. A properly insulated garage floor can help regulate temperature, prevent moisture issues, and create a more pleasant environment for various activities.

Whether you plan to convert your garage into a workshop, home gym, or simply want to protect your belongings, insulating the concrete floor is a relatively straightforward process that can yield significant benefits. In this guide, we’ll walk you through the steps to effectively insulate your concrete garage floor.

Understanding the Benefits of Insulating a Concrete Garage Floor

Before diving into the how-to, let’s first understand the reasons why insulating a concrete garage floor is worth the effort:

  1. Temperature Regulation: Uninsulated concrete floors tend to absorb and retain cold temperatures, making the garage space chilly and uncomfortable during the winter months. Insulation helps to create a thermal barrier, retaining heat during cold weather and keeping the area cooler in summer.
  2. Moisture Prevention: Concrete is porous, which means it can absorb moisture from the ground below or seep through cracks. Moisture infiltration can lead to mold growth, degradation of the concrete, and potential damage to stored items. Insulating the floor helps prevent moisture from reaching the surface.
  3. Energy Efficiency: If your garage is attached to your home, an insulated floor can contribute to overall energy efficiency. When your garage is better insulated, it can help regulate the temperature of the adjacent rooms, reducing the load on your heating and cooling systems.
  4. Noise Reduction: A layer of insulation can also act as a noise barrier, minimizing the transmission of sound between the garage and the rest of the house.

Materials You’ll Need:

  • Insulation Boards: Choose rigid foam insulation boards with high R-values for the best thermal performance. Common options include extruded polystyrene (XPS) or polyisocyanurate (PIR) between 50mm and 100mm thick
  • DPM: Always worth laying a damp proof membrane before the insulation to ensure damp cannot rise through the existing floor.
  • Concrete or chipboard flooring: Either screed over the insulation or lay 2.4m x 0.6m T&G flooring boards for a floating floor.
  • Safety Gear: Wear gloves, safety glasses, and a dust mask when cutting and handling insulation materials.

Step-by-Step Guide:

  1. Prepare the Garage: Clear the garage floor of any items and sweep it thoroughly to remove dust and debris.
  2. Lay the DPM: Lay the damp proof membrane on the subfloor and turn it up the wall. Later, trim to finished floor height.
  3. Measure and Cut Insulation Boards: Measure the dimensions of your garage floor and mark the measurements on the insulation boards. Use a straightedge and a wood saw to cut the boards to fit the floor space precisely. Remember to leave a small gap (about 3mm) around the edges to allow for expansion. Bring a thin piece (25mm to 50mm) up level to finished floor height around the whole of the perimetre to prevent cold bridging.
  4. Lay Flooring: Either Lay the floor boards on the insulation, glueing the joints with a suitable adhesive, or apply a concrete screed approximately 50mm minimum thickness on top of the insulation boards.
  5. Seal Gaps: Inspect the edges and seams of the insulation boards. If you notice any gaps or joints, fill them with expanding foam or similar to create a continuous and airtight layer.
  6. Cover the Insulated Floor: Once the insulation and flooring is in place, you can choose to cover it with various flooring materials to enhance the appearance and functionality of your garage. Common options include, vinyl, epoxy coatings, or rubber flooring tiles. The choice of flooring will depend on your specific needs and budget.
  7. Insulate Garage Doors: For maximum energy efficiency, consider insulating your garage doors as well. Garage door insulation kits are available, and they can make a significant difference in maintaining a comfortable temperature inside the garage.


Insulating a concrete garage floor is a practical and rewarding project that can significantly improve the functionality and comfort of your garage space.

By creating a thermal barrier and preventing moisture issues, you can transform your garage into a versatile area suitable for various activities. With the right materials and a bit of effort, you can create a more energy-efficient and inviting environment, making your garage a valuable extension of your home.

Ensure you have sufficient head height before completing the project, and box in to create a step or ramp at door thresholds.

Remember to follow safety guidelines and take the necessary precautions when working with insulation materials. With a well-insulated garage floor, you’ll have a more enjoyable space for your hobbies, projects, and storage needs throughout the year.

Contact us for a no-obligation quote or more information…