How to Insulate Brick Walls From Outside?
To insulate brick walls from the outside, a common method is to cover the existing brick with rigid foam insulation.
Insulating brick walls from the exterior is an effective way to improve energy efficiency and comfort in a home. Unlike insulating from the inside, exterior insulation allows the brick wall to stay warm, which helps prevent moisture issues within the wall structure itself. This process typically involves installing a layer of insulation on the exterior surface of the brick, followed by a new weather barrier and exterior cladding.
Based on common practices and the provided reference, one primary method for insulating brick walls from the outside involves applying rigid foam directly over the existing brick surface.
Here's a general breakdown of the process:
- Prepare the Wall: Ensure the existing brick wall is clean, dry, and in good repair. Any cracks or damaged mortar should be fixed.
- Install Rigid Foam Insulation: Rigid foam boards (like EPS, XPS, or polyiso) are attached directly to the exterior surface of the brick wall. The thickness of the foam will depend on the desired R-value and local building codes. Multiple layers might be used.
- Seal Seams: The seams between the rigid foam boards are typically sealed with tape or caulk to create a continuous thermal barrier and prevent air leakage.
- Add a Weather Barrier: A weather-resistive barrier (WRB) is installed over the rigid foam. This layer protects the insulation and the wall structure from moisture penetration while allowing vapor to escape from inside.
- Create a Rainscreen Gap (Optional but Recommended): In many systems, vertical furring strips are attached over the WRB. These strips create a small air gap (rainscreen) between the insulation layer and the final siding, promoting drainage and drying behind the siding.
- Install New Siding/Cladding: Finally, a new exterior finish is installed over the furring strips or directly onto the rigid foam (depending on the system). This could be siding (vinyl, fiber cement, wood), stucco, or other suitable exterior claddings.
This approach, which includes covering the existing brick with rigid foam, is a direct way to add substantial insulation value to the exterior of a brick home. While the reference also mentions removing siding from concrete block and then insulating, for existing brick walls, applying rigid foam directly over the brick is the relevant exterior insulation strategy highlighted.
This method effectively moves the thermal boundary to the outside of the original brick structure, helping to keep the building warmer in winter and cooler in summer, while also protecting the brick itself from extreme temperature fluctuations.
