Benchmarking - What Is It? Five Reasons Why I Do It Every Time

In terms of diagnosing foundation issues and designing solutions to fix them, benchmarking is the process of taking measurements using various tools and noting those metrics at the measurement location shown on a floor plan or map. The primary tool that I use is a self-leveling rotating laser, which can rotate horizontally to show a level line, or vertically to show a plumb line. So, why is benchmarking a useful tool for a foundation repair Design Specialist?

Snapshot in Time

How can we tell if a suspected foundation issue is changing over time? Well, it’s often pretty easy to see. But if we can quantify sinking, shifting, tilting, a bow or bend, even frost heave, and then log those metrics, we can track over time to determine if a foundation wall, floor support system, concrete slab, or load-bearing post/column is changing and by exactly how much. This can dictate the best long-term fix in many situations.

The Numbers Paint A Picture

We can confidently determine what is going on with a foundation issue with complete measurements from various critical areas of a home. The more data points and the more different measurement areas, the better we can visualize and understand what is happening with the foundation or support system. For instance, we can measure a sag in the main beam in two spots, but if it’s the same measurement of 0” on either end, we wouldn’t even note the 2” low spot in the center! By taking 5 measurements left to right, we could get much more useful information, like 0” down, 1” down, 2” down, 1” down, and back to 0”.

Specific Measurements - Hard Data

Minimizing guesswork and speculation is certainly useful in determining if a foundation problem exists. A lot of times, there is no question in what your speculation is - you can clearly see that there is something wrong! But no matter how extensive visible damage may be, having hard data is essential. For instance, a foundation wall being pushed in from soil from the outside and a foundation wall’s footing sinking/settling could exhibit the same symptoms (for instance, cracks in the wall). However, the fix between those two root issues is drastically different. 

Leads to the Issue Downstairs

Benchmark measurements from the main level floor are extremely useful to corroborate visible foundation elements downstairs in the basement or crawlspace, or even under a porch or addition. By taking multiple measurements from a level horizontal line down to the main level floor, we can see foundation settlement, floor support problems such as beam/floor joist issues, inward wall movement. Main level floor level readings are not always the best or highest-confidence measurement we can take - sometimes the subfloor is built strangely with questionable carpentry techniques, or if moisture has had an effect - but it is always a useful set of numbers to log. If we pick up a low spot in the floor uniformly on the north side, it makes sense to take a very close look at the north foundation wall! It’s common to have visible issues hidden by layers of paint, finished walls, shelving or cabinets.

Can Corroborate With Multiple Data Points

Benchmarking and saving the measurements allows us to compare all areas and data points. Without logging our measurements, we can’t corroborate and compare different areas that we’re measuring, or different types of measurements. For instance, by saving 8 measurements from the upstairs floor levels, and measurements off of a plumb line from all four foundation walls, we can explain why cracks in drywall towards the corner of the east walls are caused by soil on the east wall pushing in, dropping the floor, and causing stress on the drywall from below. In another example, we can confidently diagnose foundation settlement if measure consistent decreasing metrics from left to right, for example, from the mortar joints of the block foundation wall in the basement, and from the exterior siding, and from the main level floors, from the basement floor joists, and have a crack and hear a void under the basement slab.