What Are “Modified” Soils Reports?

Considering some new construction on your home? Here’s something you should definitely familiarize yourself with: some jurisdictions (such as the city of Glendale) allow for analyses known as “modified soils reports” for small addition projects.

So, what are modified soils reports? Typically these involve a short site visit by a soils engineer, followed by a very brief report. This report provides a description of the soil in the general vicinity based on prior experience, minimum bearing values, and dimensions for footings. It will include a requirement to conduct field observations during footing excavations to ensure the assumptions regarding the subsurface strata made in the modified report are generally correct (for example, no deep fill or unusual soil horizon is present).

The modified soils report may be accompanied by a site plan drawing of the proposed addition. No investigation of the site is performed, nor are there any laboratory tests conducted. Owners are often glad to hear a modified soil report will be allowed by the building department, because modified reports are significantly less costly than traditional geotechnical reports which require site investigation and laboratory testing.

However, even if the local building agency allows for a modified soils report, not all sites are suitable for this approach. Sometimes a planned addition or structure is situated in an area of transition soils, or uneven ground, or near slopes. In such cases, experienced soils engineers will not feel comfortable providing minimum requirement recommendations if the soils in the area of the planned additions may be variable or more complex.

If the subsurface conditions are in any way different from the suppositions made by the engineer, these can lead to delays during construction and other problems, and needless to say, plenty of finger pointing and liability exposure for the engineer. In such cases, when we are not comfortable making assumptions about the subsurface conditions in the area of the planned additions, we will recommend a minimum investigation be conducted.

When all is said and done, the allowance of modified soils reports can be a huge cost saver for people in Glendale seeking to add onto their home. And of course, the veteran team at AES Soil will always make a calculated and professional judgement about whether your unique project is suitable for this special analysis. Wondering if your project qualifies? Contact AES Soil today!

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