Rigid Board Insulation

Rigid Board Insulation (Continuous Insulation)

Rigid board insulation (or foam board) is a highly effective solution for adding thermal resistance to complete building assemblies. Unlike cavity insulation (such as batts inside a wall), rigid board is typically installed as "continuous insulation" over framing, sheathing, or masonry, reducing thermal bridging and improving overall energy performance.

Structo Insulation installs rigid foam systems for exterior walls, foundations, roof decks, and specialized applications where high compressive strength and moisture resistance are required.

Why Continuous Insulation Matters

In standard wood or metal frame construction, the studs act as "thermal bridges," allowing heat to bypass the insulation in the cavities. This can reduce the effective R value of a wall by 15-20% or more.

Continuous insulation covers the framing, creating an unbroken thermal blanket that minimizes heat loss and improves the efficiency of the entire assembly.

Benefits of Rigid Board Insulation

High R value per inch
Rigid foam provides excellent thermal resistance with minimal thickness.

Moisture resistance
Most rigid foam products are resistant to water absorption, making them ideal for below grade applications and exterior sheathing.

Compressive strength
Rigid board can withstand pressure, allowing it to be used under concrete slabs, roofing membranes, and exterior siding.

Air barrier contribution
When widely sealed, rigid foam acts as an air barrier, reducing drafts and air infiltration.

Common Applications

• Exterior walls: Installed behind siding or masonry to break thermal bridging.
• Basement walls and foundations: Applied to concrete surfaces to control temperature and minimize condensation potential.
• Under slab insulation: Placed below concrete floors to prevent heat loss into the ground.
• Low slope roofing: Used as a thermal base layer for roof membrane systems.

Types of Rigid Board Insulation

Structo Insulation installs industry standard rigid foam products, including:

Expanded Polystyrene (EPS)
Cost effective and versatile, adaptable for walls, roofs, and foundations.

Extruded Polystyrene (XPS)
Higher density and moisture resistance, often used for below grade and slab applications.

Polyisocyanurate (Polyiso)
Highest R value per inch, commonly used for roof insulation and exterior wall sheathing.

Request an Insulation Evaluation

Rigid board insulation is a specific component of a high performance building envelope. Determining where and how to use it requires an understanding of the entire assembly.

Request an insulation evaluation to determine how rigid board insulation can improve the energy efficiency and durability of your project.