2.7: Thermal Insulation in Masonry Walls

In hot, dry climates, the thermal mass of masonry walls can be beneficial, absorbing heat during the day and releasing it at night, thereby stabilizing indoor temperatures. However, in most other climates, additional insulation is necessary to enhance thermal resistance.

External insulation can be applied using an Exterior Insulation and Finish System (EIFS), which involves affixing panels of plastic foam to the wall and covering them with a polymeric stucco reinforced with glass fiber mesh. This method not only improves insulation but also protects the masonry from temperature extremes, making it a popular choice for retrofitting existing buildings where preserving the exterior appearance is not a priority.

Insulation within the wall is another approach, involving the insertion of plastic foam slabs against the inner wythe during construction or filling the hollow cores of concrete blocks with foam liners. While effective, this internal insulation does not impede heat transfer through the masonry's solid sections, such as the webs of the blocks or fully grouted areas, somewhat limiting its efficiency.

Insulating the interior surface of masonry walls is also feasible. This typically includes attaching insulation directly to the wall followed by wood or metal furring strips. Interior finish materials, like gypsum wallboard, are then mounted on these strips. This method not only enhances thermal insulation but also creates a convenient void for hiding electrical wiring and plumbing, addressing a common challenge in masonry construction.

Masonry walls can be thermally insulated to minimize heat loss in the winter and heat gains in the summer.

Thermal insulation can be done on the exterior wythe, interior wythe, and between the wythes.

A building with panels of polystyrene foam attached to the exterior wall, which are then covered with a layer of polymeric stucco and reinforced with glass fiber mesh, is externally insulated.

Similarly, internal thermal insulation can be achieved by attaching reflective barriers or batt insulation to the interior wall surface using furring strips, followed by the installation of a gypsum wallboard to create a concealed space to house the utilities.

Moreover, maintaining a sufficient air gap between the wythes, inserting slabs of plastic foam within this space, or filling granular insulation, such as perlite, in the cavity between brick wythes helps to thermally insulate the walls."

Nevertheless, for heavily reinforced walls, rebar serves as thermal bridges, and the limited space for insulation leads to reduced thermal insulation.

The choice of thermal insulation depends on building function, building code regulations, and a cost-benefit analysis.

• Masonry Walls - Large structures built from individual blocks or bricks, often requiring insulation.
• Thermal Mass - The ability of a material to absorb and store heat energy.
• External Insulation and Finish System (EIFS) - A method of insulating walls externally for improved thermal resistance.
• Hollow Masonry Wall Insulation - Filling the hollow cores of blocks or bricks with insulating material.
• Interior Wall Insulation - Applying insulation on the inner surface of masonry walls for enhanced thermal resistance.

• Define Insulation for Masonry Walls – Explaining how insulation material is designed and used to enhance thermal resistance and stability of masonry constructed walls (e.g., insulation).
• Contrast External and Internal Insulation – Detail the differences between insulating a wall externally vs internally (e.g., EIFS vs hollow masonry wall insulation).
• Explore Insulation Materials - Describe the common materials used for insulating masonry walls (e.g., plastic foam, foam liners).
• Explain the Role of Insulation in Temperature Management – Detail how insulation manages temperature extremes within masonry construction (e.g., by absorbing and radiating heat).
• Apply Insulation Techniques – Discuss practical applications of various insulation techniques in real-world contexts (e.g., retrofitting).

• What is the purpose of insulation for masonry walls and how does it help with thermal management?
• How are exterior and interior wall insulations different in their applications and efficiency?
• What types of materials are commonly used for insulating masonry walls?

• Students of Building Trades – Understand how insulation supports energy efficiency and thermal management in masonry wall construction.
• Builders and Contractors – Gain insight into the practical aspects and benefits of utilizing various insulation techniques.
• Architects and Engineers – Learn various techniques of insulation that can be applied to enhance the thermal resistance of buildings.
• Renovation Specialists – Understand the importance and methods of insulating pre-existing masonry walls, especially for retrofitting projects.