ahewett@uselman
Member
I'm frustrated to see standard foundation design on questionable soils. We receive quite a few calls each year from homeowners for repairing standard foundation systems placed directly on expansive soils. I have researched residential code and found a very complex responsibility trail. Anybody have any input? I have tried talking to the local inspector about this subject, but I am not getting anywhere.
Here is a example.
The IRC 2009 R401.4 changes here in New Mexico, with an amendment, 14.7.3.12
• International Residential Code for One- and Two-Family Dwellings
o [ 2009 (Fifth Printing) ]
R401.4 Soil tests. Where quantifiable data created by accepted soil science methodologies indicate expansive, compressible, shifting or other questionable soil characteristics are likely to be present, the building official shall determine whether to require a soil test to determine the soil's characteristics at a particular location. This test shall be done by an approved agency using an approved method.
New Mexico changes to IRC 2009
14.7.3.12 CHAPTER 4 FOUNDATIONS:
A. Section R401. See this section of the IRC except as provided below: Section R401.4 Soil tests. Delete the text of this section and replace with the following. Where quantifiable data created by accepted soil science methodologies indicate expansive, compressible, shifting, or other questionable soil characteristics are likely to be present at a particular location, a soil test to determine the soil’s characteristics at a particular location shall be performed.
This seems like the only code is to force testing. Cannot find a code direction to do anything with the soils report, if it was showing a poor soils condition.
I am also considering this line from IRC 2009 below. I cannot find the reference: 1805.8 of the 2009 IBC. 1805.4.3 Drainage discharge is the last entry in my copy of code for chapter 18. But it almost looks like IRC2009 - R403.1.8 tries to kick the problem up to the steeper requirements of commercial building code.
R403.1.8 Foundations on expansive soils. Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1805.8 of the International Building Code.
Exception: Slab-on-ground and other foundation systems which have performed adequately in soil conditions similar to those encountered at the building site are permitted subject to the approval of the building official. I hope some of this makes sense to somebody.
Here is a example.
The IRC 2009 R401.4 changes here in New Mexico, with an amendment, 14.7.3.12
• International Residential Code for One- and Two-Family Dwellings
o [ 2009 (Fifth Printing) ]
R401.4 Soil tests. Where quantifiable data created by accepted soil science methodologies indicate expansive, compressible, shifting or other questionable soil characteristics are likely to be present, the building official shall determine whether to require a soil test to determine the soil's characteristics at a particular location. This test shall be done by an approved agency using an approved method.
New Mexico changes to IRC 2009
14.7.3.12 CHAPTER 4 FOUNDATIONS:
A. Section R401. See this section of the IRC except as provided below: Section R401.4 Soil tests. Delete the text of this section and replace with the following. Where quantifiable data created by accepted soil science methodologies indicate expansive, compressible, shifting, or other questionable soil characteristics are likely to be present at a particular location, a soil test to determine the soil’s characteristics at a particular location shall be performed.
This seems like the only code is to force testing. Cannot find a code direction to do anything with the soils report, if it was showing a poor soils condition.
I am also considering this line from IRC 2009 below. I cannot find the reference: 1805.8 of the 2009 IBC. 1805.4.3 Drainage discharge is the last entry in my copy of code for chapter 18. But it almost looks like IRC2009 - R403.1.8 tries to kick the problem up to the steeper requirements of commercial building code.
R403.1.8 Foundations on expansive soils. Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1805.8 of the International Building Code.
Exception: Slab-on-ground and other foundation systems which have performed adequately in soil conditions similar to those encountered at the building site are permitted subject to the approval of the building official. I hope some of this makes sense to somebody.