Choosing Insulation for Precast Walls

Precast Image with Macro

Cost is king, and with the cost of everything from building materials to energy rising, everyone from architects to building owners and operators are looking for ways to manage construction and operational budgets.

Precast concrete walls are one way to address both. Rather than conventional tilt-up walls, which must be poured and assembled on-site, precast walls are manufactured off-site and brought to the job site only when the contractor is ready to install them. The result is a wall system that:

  • Needs fewer tradespeople to install.
  • Improves scheduling efficiencies for installation.

  • Requires less space on-site for raw material storage and assembly.

  • Comes as a complete building envelope, including exterior finishes, moisture barrier, insulation and interior finishes.

  • Can replace not only conventional wall assemblies, but also other traditional building elements like cast-in-place concrete or steel columns.

  • Includes improved wind and seismic resistance.

  • Comes with quality control, since precast walls are built in an indoor facility and are not subject to weather the way tilt-up systems are.

  • Has a higher thermal mass than other conventional building materials, which can reduce energy demands, especially during peak usage.

  • Needs less maintenance, particularly on exterior cladding and finishes.

  • Is fire resistant.

  • Contributes to a lower environmental impact during installation.

Precast concrete wall systems are easily customizable to your project. The concrete panels, or wythes, come in a variety of thicknesses to suit your design. While concrete has some insulative properties, precast concrete walls are fitted with rigid foam insulation to improve their energy efficiency.

The most common types of insulation used in precast concrete walls are:

  • Expanded polystyrene (EPS)

  • Extruded polystyrene (XPS)

  • Polyisocyanurate

The insulation chosen will depend on factors including the desired R-value, cost, building conditions and surrounding climate. For example, while polyisocyanurate often has the highest-rated R-value of the three materials, its insulation properties start to deteriorate below 59 degree Fahrenheit (15 degrees Celsius) and is not well-suited to sub-zero temperatures.

K20 side image

Another issue to consider is thickness. With the growing focus on energy efficiency in building construction and management, adding more insulation was the go-to solution for a long time. But with more and more builders requiring R-values in the 30s and 40s, there is a point at which walls become too thick to manage traditional window and door assemblies, not to mention the loss of interior square footage.

Kingspan’s Kooltherm K20 Concrete Sandwich Board and GreenGuard XPS Insulation are designed to give optimal insulation for even the thinnest walls. They provide insulation and act as a moisture barrier, without requiring additional customization which would add thickness to precast concrete walls.

Kooltherm is the thinnest commonly-used insulation on the market. Some of the features of Kooltherm K20 insulation include:

  • R-values up to 17 per two inches of insulation
  • Excellent fire performance

  • Negligible smoke development

  • Consistent thermal performance by reducing moisture intrusion

  • No air infiltration

  • No irritating fibers during installation

  • Zero Ozone Depletion Potential and low Global Warming Potential

Standard features of GreenGuard include:

  • R-value of 5 per inch of insulation

  • Continuous insulation for walls and floors

  • Extra barrier against moisture intrusion

  • Meets required fire ratings for each product’s intended use

Stubbes Building Image

Kooltherm, in particular, has been used in a number of higher profile precast concrete projects. When builders are looking to maximize insulation and minimize wall thickness, Kooltherm is an ideal insulating material. It has been used in facilities such as warehouses, meatpacking plants and data centers. In all these cases, consistent insulation is critical to their day-to-day operations, and Kooltherm delivers.

Precast concrete wall systems offer a wide variety of benefits, both during construction and for the years of building operation that follow. It is both energy efficient and durable, and choosing the right insulation for your precast concrete walls is a critical step in ensuring you are able to take advantage of all the benefits precast concrete has to offer.

Form more information on how Kingspan insulation can help you manage building costs from construction to occupancy and beyond, click here to visit our website.

Kingspan Insulation North America

Head Office & Sales Office – North America

Kingspan Insulation LLC

2100 Riveredge Parkway, Suite 175

Atlanta, Georgia



Call: +1(800) 241 4402