When planning the architectural elements that will decorate your property, it is always a good idea to think beyond the more common challenges and costs, and consider the factors that might affect the long term satisfaction of the property owner.
Expanded Polystyrene (EPS) is commonly used in architectural elements due to its lightweight composition, design flexibility, and insulating properties. When coated with a durable cementitious layer, EPS becomes suitable for exterior and interior applications where durability and resistance to environmental stress are essential.
Most of the time, when considering architectural EPS, the focus is on the designs that this type of product makes possible and the ease of installation, among other things. But what about the factors that might affect the owner? For example, how does architectural EPS stand up to pest intrusions – particularly insects, rodents, or other burrowing animals?
Cement coated architectural EPS products demonstrate strong resistance to pest activity when properly manufactured and installed.
Inherent Properties of EPS That Influence Pest Behavior
EPS itself is not a food source for pests. Unlike wood or organic insulation materials, EPS does not provide nutrients that attract rodents or insects. That means that, in a general sense, there is no risk of pests desiring the material itself. It is thus inherently pest resistant.
However, it is a soft material that – if left exposed or unprotected – can be physically burrowed into or used as nesting material. Luckily, this vulnerability is greatly reduced when the EPS is encased in a rigid, dense cementitious layer.
Pest Resistance Benefits of Cement Coating
The cement coating applied to architectural EPS elements serves both a structural and protective function. From a pest resistance perspective, it acts as a durable physical barrier that prevents access to the EPS core.
When properly applied and cured, like the products we offer here at Patterson Whittaker, the cement coating offers:
- Mechanical Resistance to Burrowing – Rodents and insects are physically unable to chew or tunnel through the hardened outer layer.
- Surface Hardness That Discourages Nesting – Unlike exposed foam, the cement surface does not retain warmth or allow easy excavation.
- Moisture Resistance – Properly sealed coatings reduce water intrusion, which helps prevent secondary infestations such as termites or carpenter ants that seek out damp material.
- Reduced Access Points – Installed architectural EPS components that are bonded, sealed, and integrated into the building envelope leave fewer gaps that could serve as pest entryways.
Its light weight also provides additional benefits. Because these products require essentially no additional mechanical reinforcement, no openings need to be created in the weather resistant barrier. There will not even be a single hole that allows pests to enter as a result of not only the product itself, but installation methods.
Limitations and Considerations
While cement coated EPS is generally pest-resistant, it is not completely pest-proof under all conditions. Pests are more likely to exploit improperly sealed seams, mechanical damage to the coating, or interfaces where the EPS meets dissimilar materials.
In areas of high rodent activity, the following precautions may be recommended:
- Inspect joints and connection points for gaps or cracks
- Ensure that the cement coating is continuous and free of breaks
- Avoid using uncoated EPS in exposed or ground-contact applications
- Combine EPS systems with exclusion methods, such as physical barriers or steel mesh, in vulnerable zones
The products themselves will be extremely effective, but installation quality is still going to play a role in the long term pest prevention success of the material.
Overall Performance in Pest-Prone Environments
When installed to specification and maintained properly, cement coated architectural EPS is considered highly effective against most common indoor and outdoor pests. It offers a significant improvement in pest resistance over raw foam, and in many cases, performs comparably to traditional materials such as stucco or concrete panels in deterring pest intrusion.
For applications where durability and pest resistance are required – such as soffits, cornices, or façade elements – cement coated EPS provides a lightweight, versatile, and low-maintenance alternative that meets both functional and aesthetic goals.
