Essential Guide to Permanent and Temporary Structural Support Posts

As a home inspector, I often find myself in the hard-to-access and often unvisited areas of homes, uncovering the often unseen yet vital components that keep a home standing strong. One of the most critical things I encounter is the structural support system, especially in basements. These supports, often overlooked, are the unsung heroes of a home's structural integrity. Understanding the difference between the different types of support posts and how they're installed is crucial for homeowners in maintaining the long-term stability and safety of their home.

In modern homes, steel structural support posts, or columns, are commonly used. There are two main types of steel support posts: single-piece and multiple-piece (telescopic) columns. It's important to use the right type of column and install it correctly to prevent future structural issues. These support posts play a crucial role in transferring the weight of the home to the basement floor, usually connecting to a wood or steel I-beam at the foundation walls.

Permanent Support Posts

Permanent support posts, usually single-piece and made of steel, are the go-to for long-term stability. They're typically hollow, with a minimum diameter of 3 inches, and should have an ICC or BOCA sticker indicating third-party certification to meet specific design criteria. Although the sticker could be removed post-installation, a permanent post will have an adjustable end and a flat steel plate end. It can be installed with the adjustable end either up or down, but it's crucial that the bottom end is securely cemented or bolted into the basement floor.

According to the International Code Council (ICC), it's necessary for an engineer, architect, or builder to ensure that these posts can appropriately support the home's load and that they're installed in the correct locations.

Temporary Support Posts

On the other hand, temporary support posts, often smaller than 3 inches in diameter, are not meant for permanent use. Known as 'jack posts' or 'lally columns,' these are used for temporary tasks like gradually lifting a house. Once the lifting is completed, permanent columns should replace these temporary supports. However, I've noticed in my over a decade of experience that temporary posts are sometimes left as the only support, which is not ideal.

These multi-piece posts have smaller sections fitting inside larger ones, fixed in length by a metal dowel. No multi-piece support less than 3 inches in diameter is certified for permanent use. Finding these as permanent posts is a defect needing immediate attention, often indicating non-professional structural work that might lack proper engineering or permits.

Choose Permanent Posts Over Temporary Posts

Temporary-rated posts can't handle the same weight load as permanent ones. Over time, the weight of a home can cause these temporary posts to bend, bow, or even break. Don't be fooled by a temporary post that looks undamaged – it may not be safe. Homes adjust to the weight distribution of their contents, and changes in ownership can lead to resettlement issues, visible in new cracks or sticky windows and doors. Extreme cases might reveal damaged structural components like joists, rafters, or support posts. Rust damage, especially from flooding, is a red flag, as it can significantly weaken a steel post.

Regardless of which post type you use, a correctly installed support post should be vertical and plumb. If not, it could indicate amateur installation or structural movement post-installation. Home inspectors are not licensed structural engineers, so we recommend consulting a licensed structural engineer for any issues with structural support posts. Even if repairs seem well done, it's wise to inquire about the nature of the repair, the qualifications of those who performed it, and any warranty documentation.

In summary, choosing and installing the right type of support post in your home is crucial for its long-term stability. As a home inspector, my goal is to help you understand these differences and the importance of professional installation and maintenance for the safety and integrity of your home. Remember, a home inspection is a visual and non-invasive examination, but it plays a vital role in ensuring the overall health of your home's structure.

For expert advice and thorough home inspections, consider consulting professionals like WIN Home Inspection, who can provide detailed insights into the structural soundness of a home.

Author Bio:

Josh Rogers

As a former professional home inspector and Training Specialist at WIN Home Inspection, Josh has years of experience in both performing and teaching home inspections, infrared scans, radon testing, mold testing, and more.