• How to Install Foil Insulation on Walls

    | by Holly Wood

    If you’re looking to enhance the thermal efficiency of your home and reduce energy bills, learning how to install foil insulation on your walls can be a great solution.

    Foil insulation, also known as reflective foil insulation, radiant barrier, or multifoil insulation, is designed to create a reflective surface. This reflective surface acts as a barrier to radiant energy, making it highly effective for both internal and exterior walls.

    In this comprehensive guide, we will take you through the steps to properly install foil insulation on your walls, ensuring that you achieve the desired thermal performance.

    Materials You’ll Need To Install Foil Wall Insulation:

    Before you begin, gather the following materials:

    1. Foil insulation (e.g., Superfoil insulation or Superquilt insulation)
    2. Thermaseal foil joining tape
    3. Heavy-duty staple gun
    4. Treated timber battens
    5. Counter battens (optional for extra thermal benefits)
    6. Fixing materials recommended by the insulation manufacturer
    7. Foiled-back plasterboard or insulated plasterboard (if you plan on installing it)
    8. Rigid PIR insulation (if required)
    9. Staple gun
    10. Tapes to ensure fully taped joints

    Step 1: Prepare Your Walls

    Before you start installing foil insulation, ensure that your walls are clean and free from any debris. Additionally, if you are working on refurbishment projects, it’s crucial to address any existing issues with your walls, such as dampness or structural problems, before proceeding.

    Step 2: Calculate the Desired U-Value

    To determine the thickness of insulation needed, use an online U-value calculator specific to your region and the type of insulation you plan to use. The U-value represents the thermal performance of your insulation, and it should meet the recommended standards for your area.

    Step 3: Install Timber Battens

    Fix treated timber battens to your walls vertically at the recommended batten depth. These battens provide a secure frame for the insulation and help reduce compression, ensuring the insulation functions optimally year-round.

    Step 4: Install Counter Battens (Optional)

    For extra thermal benefits, you can install counter battens horizontally on top of the vertical battens. This creates an air gap that further enhances thermal performance, especially for solid walls. Make sure they are fixed perpendicular to the vertical battens.

    Step 5: Fit Foil Insulation

    Roll out the foil insulation horizontally across your wall, starting from the bottom and working your way up. Ensure that it covers the entire wall and that any overlaps are fully taped using Thermaseal foil joining tape. This step is critical to maintaining the integrity of the vapour control layer.

    Step 6: Staple Foil Insulation

    Staple the foil insulation to the timber battens using a heavy-duty staple gun. Ensure that the insulation is taut and securely fastened to prevent any sagging or gaps.

    Step 7: Install Insulated Plasterboard (Optional)

    If you plan to add an extra layer of insulation, you can install insulated plasterboards over the foil insulation. Follow the manufacturer’s recommendations for fixing them in place.

    However, please note, that you are not obligated to utilise foil-backed plasterboard if your chosen foil insulation incorporates a vapour control layer (such as Superquilt). This allows you to cut down on extra expenses for your project.

    Step 8: Check for Gaps and Overlaps

    Inspect the entire installation to ensure that there are no gaps or overlaps in the foil insulation. Any gaps can compromise its thermal efficiency.

    Step 9: Seal Joints and Edges

    Ensure that you use tapes to fully seal all joints and edges of the foil insulation. This step is crucial for maintaining the vapour control layer and preventing air leakage.

    Step 10: Finish the Wall

    Once your foil insulation is fully installed and sealed, you can finish the wall with your desired wall covering, whether it’s paint, wallpaper, or another finish.


    By following these steps and using high-performance multifoil insulation products, you can greatly reduce heat loss through your walls, improve your home’s thermal efficiency, and ultimately lower your energy bills.

    Remember that this guide provides a general overview of how to install foil insulation on walls. It’s essential to consult the manufacturer’s instructions for the specific product you are using, as different multifoil insulation products may have slightly different installation requirements.

    Additionally, always adhere to good building practices and seek professional advice when necessary to ensure a successful insulation project.

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