Modern homes, especially those built in high seismic regions, are typically constructed to meet updated building codes that account for earthquake resilience. Since building standards have advanced significantly in recent decades, homes built to relatively recent codes already include key seismic detailing to protect against ground shaking and lateral forces. However, even modern homes may benefit from additional retrofits to enhance resilience further. Here’s a guide to understanding seismic detailing in newer homes and how homeowners can strengthen their properties against earthquakes.

In regions prone to seismic activity, building codes require residential structures to include specific design features to withstand earthquakes. For example, reinforced connections between the foundation, walls, and roof are required to manage lateral forces, while foundation anchors and steel reinforcements help keep the structure stable during shaking.

Homes built in recent decades are generally equipped with these features, providing a strong foundation of seismic resilience. Modern codes focus on securing the building’s structural components—such as the foundation, framing, and roof—so they move together rather than separating or collapsing during an earthquake. As a result, newer homes are less likely to experience catastrophic damage compared to older structures with minimal or no seismic detailing.

One of the most accessible areas to observe seismic detailing in a modern home is within the crawlspace. Common seismic features found in modern crawlspaces include:

• Foundation Anchors: Metal anchors that connect the foundation to the mud sill or base framing help prevent lateral movement.

• Shear Walls: These walls are designed to resist horizontal forces and may include plywood or steel bracing.

• Steel Connectors: Metal connectors between framing components provide added stability and resistance to separation.

When reviewing a modern home’s crawlspace, it’s essential to check if seismic detailing aligns with the age of construction and current codes. If any foundation improvements were made after the original construction, such as the addition of plate washers or enhanced shear walls, these can be noted as positive reinforcements.

While modern homes are built to comply with current standards, additional improvements can still strengthen their earthquake resilience. For homeowners looking to enhance their property’s seismic detailing, the following upgrades are recommended:

In some cases, replacing standard plate washers with larger versions can help distribute loads more effectively during seismic events. Larger washers provide increased contact area, creating a stronger and more stable connection between the foundation and the framing. This upgrade is relatively low-cost but can make a meaningful difference in performance.

Adding extra metal framing connectors can improve the structure’s lateral stability, especially in areas where the framing bears significant load. Steel connectors that secure floor joists, wall studs, and roof trusses offer additional protection against shifting during seismic activity.

Modern homes often include shear walls to resist lateral forces, but homeowners can upgrade these with additional bracing or plywood sheathing if desired. Improved shear walls help prevent walls from bowing or collapsing under the stress of an earthquake, providing enhanced structural support.

Adding more anchors or upgrading existing ones can increase the home’s seismic resilience. Foundation anchors that connect the base framing to the concrete foundation keep the structure stable, reducing the risk of shifting or separation.

Although modern homes generally comply with current seismic requirements, additional retrofitting can still be beneficial. For homeowners, retrofits offer peace of mind and enhanced protection against potential earthquakes. Retrofitting is especially recommended for homes located in high seismic zones, where even a small improvement in detailing can make a difference in structural performance.

As with any property, assessing risk tolerance is a key factor. Some homeowners may choose to retrofit proactively, while others may prefer to monitor and make improvements as needed. Generally, it’s advisable to reinforce seismic detailing when the opportunity arises, especially if planning renovations that would expose framing or foundation elements.

While modern homes are constructed to high seismic standards, there are still opportunities to improve resilience through targeted retrofitting. Adding larger plate washers, reinforcing shear walls, and upgrading foundation anchors can all provide extra security, particularly in high seismic regions. In general, retrofitting is a valuable investment that offers additional safety and peace of mind, ensuring that the structure is as prepared as possible to withstand seismic events.