Code Conundrums: Foundation Anchorage

Code interpretations and commenting on building codes are beyond the purview of the home inspector during an inspection. However, background knowledge of the codes can
be helpful in many instances.

In this installment of “Code Conundrums,” we’ll explore more issues that may arise during inspections, how they are related to the building code, and why sometimes the code and best practices are not aligned. Let’s focus this issue on foundation anchorage.

REAL-LIFE CASES

Pre-purchase home inspections were performed recently on a 10-year-old house and on a new construction house. In both cases the houses have their Certificates of Occupancy (CO) from the local Authority Having Jurisdiction (AHJ). Each AHJ was a different municipality. However, the framing was not anchored to the foundation properly in either house.
A third case involves a house elevation project with a new foundation and some poorly located anchor bolts.

Case 1

In the 10-year-old house, which is
located in a flood zone, anchor bolts were installed and protrude through the sill plates but do not
have nuts and washers to secure the framing
to the foundation. The anchor bolts are rusted
due to the saltwater exposure.

Case 2

In the new construction house, anchor bolts have also been installed but are not secured with nuts and washers for the framing/foundation connection. Spray foam installed for energy code requirements made the anchor bolts difficult to access. However, all 12 anchor bolts inspected did not have a nut or a washer.
The contractor of record was “surprised” when this was pointed out and insisted we were lucky to have found all the improperly secured anchor bolts. Going out on the proverbial limb, we made the assumption that all anchor bolts were not properly secured and pointed this out to the prospective buyer. The buyer became wary of the contractor’s finished work in the remainder of the house due to this concern.

Case 3

The third case is for a house elevation project with new foundation in a flood zone. To the contractor’s credit, most anchor bolts were installed and secured properly to the foundation. Several anchor bolts were in the wrong locations on the sill plates.

Relevant Code Section

Section R403.1.6: Foundation Anchorage

(Definition from 2021 International Residential Code)

Wood sill plates and wood walls supported directly on continuous foundations shall be anchored to the foundation in accordance with this section.

Wood sole plates at all exterior walls on monolithic slabs, wood sole plates of braced wall panels at building interiors on monolithic slabs and all wood sill plates shall be anchored to the foundation with minimum half-inch diameter anchor bolts spaced not greater than six feet on center or approved anchors or anchor straps spaced as required to provide equivalent anchorage to half-inch diameter anchor bolts.

Bolts shall extend not less than 7 inches into concrete or grouted cells of concrete masonry units. The bolts shall be located in the middle third of the width of the plate. A nut and washer shall be tightened on each anchor bolt.

There shall be not fewer than two bolts per plate section with one bolt located not more than 12 inches or less than seven bolt diameters from each end of the plate section.

There are additional foundation anchorage requirements for seismic zones C, D0, D1, and D2.

(Mudsill anchors by Simpson-Strong-Tie are one possible alternative to anchor bolts.)

INSIGHT

The first two cases are in violation of the building code requirements as per the International Residential Code, yet have their Certificates of Occupancy. The third case was mostly in compliance and needed some adjustments to be in full compliance, as the CO has not been issued yet.

A home inspector, as per the ASHI Standards of Practice (SOP), is required to inspect readily accessible, visually observable, installed systems and components listed in the SOP, including structural components. As per the SOP, the inspector shall inspect structural components, including the foundation and framing and describe the foundation, floor structure and wall structure. Furthermore, the inspector is not required to provide engineering or architectural services or analysis, or offer an opinion about the adequacy of structural systems and components.

Several tornadoes occurred in December 2023 in Tennessee and caused extensive damage and loss of life. Multiple homes were found to be only secured to the foundation with construction adhesive and nails, according to local news stations who reviewed National Weather Service inspection information. These homes were reported to be approximately
25 years old.

FEMA performs post-disaster studies after natural disasters—including tornadoes, hurricanes, floods, and wildfires. In a study called “Hurricane Sandy Recovery Fact Sheet No. 2 (May 2013),” FEMA stated that all buildings must be properly anchored to resist flotation, collapse, and lateral movement.

Most home inspectors are thorough and conscientious and want to provide the best service for their clients. This will include inspecting the foundation and framing, provided there is safe access. As noted above, houses not secured properly to the foundation can result in a deadly situation. The issue arises when the owner says they have a Certificate of Occupancy and are not going to address these concerns.

The home inspector is then put in a common, unenviable position between competing interests—
in this case balancing the safety of clients versus code official approval. Just because the real estate agent provides you with a Certificate of Occupancy does
not mean it was done correctly.

The home inspector can call this out in their report, indicating that it presents a safety hazard in their opinion, while not becoming involved in a code interpretation. The home seller and client are then put on notice that the issue should be addressed, reducing any potential liability for the home inspector. Note: Some states have modified their versions of the International Residential Code and may have different requirements.

Opinions or statements of authors are solely their own and do not necessarily represent the opinions or positions of ASHI, its agents, or editors. Always check with your local governmental agency and independently verify for accuracy, completeness, and reliability.