The missing foundation

The owners of a house in Southern California decided to strengthen their home to better survive “the next big one”. They called a local earthquake retrofit contractor for a price. One of the improvements they were looking for was to bolt the wooden house structure to the concrete foundation.


The contractor arrived and, after taking exterior measurements, wiggled into the tight crawl space under the house to see what needed to be done there. When he later emerged, he reported to the home owners that a portion of their foundation was missing.

GEI was hired by their insurance company to inspect the site to identify and determine the predominant cause and approximate age of the missing foundation.

Our expert visited the residence and conferred with the owners. They showed him the report of estimated costs that had been prepared for them to install foundation bolting to comply with the voluntary earthquake preparedness provisions of their city codes. Their property was a single-family, timber-framed building, aligned principally north-south, with an integral garage to the north, built circa 1923, according to the County Tax Assessor’s office.

The living room to the residence was entered from the front door in the west wall. The floor of the southeast corner had some minor separation from the wall, but the separation was normal for a building of this age. There were no other sagging or developing cracks in existence that were the result of a missing foundation. The under-floor support was comprised of a series of 4-inch by 4-inch beams carrying 2-inch by 6-inch floor joists. The beams were supported on individual timber support posts bearing on concrete or concrete/brick amalgam pads. The property was built prior to the enactment of laws requiring permits for construction (permits were not required in the county unincorporated areas until 1933). As such, the building might not meet current standards for protection of public health and safety. The area under the front door, which was claimed to be without a foundation, did have the required support. It had stood for the last 88 years, apparently without damage. The support was provided by timber beams and concrete pads instead of the expected poured concrete foundation strip found elsewhere.

The foundation supports varied throughout the residence crawl space, but appeared to be solid. The exception to this was the support by the west end of the foundation beams on a variety of concrete/brick/stone pads and by burial in the front (west) wall foundation strip. None of the west end beam supports included any form of waterproofing that could be discerned without lifting the beams. While the beams were not currently deteriorating from dry rot, it was advised that they treat the buried and supported west ends of the 4-inch by 4-inch beams to prevent possible dry rot and/or insect attack.

Our expert also noted that the downspout by the front door was not functional and could be discharging rainwater near the foundation strip and beam-ends. Also noted was the fact that the crawl space did not meet current code requirements (most of us would describe the crawl space as claustrophobic). The current crawl space code requirements are not retroactive unless the crawl space is altered.

 

Based on the foregoing, it was the expert’s opinion that the predominant cause of the perceived missing foundation was a misinterpretation of the principles of foundation engineering and of framed construction. The approximate age of the residence was 88 years, and the foundation had been in existence since that time, with no apparent structural issues.

Auto/Garage Fire

The case of the month concerns an auto/garage fire. The vehicle manufacturer issued a recall notice for an electrical problem. The insured took his nearly new vehicle to the dealer for he required work. He picked up his car about 5 pm, drove home without incident, and parked the car in the garage. About 2 am, he was awakened by smoke and flames. The fire department extinguished the fire and determined that the fire started in the garage. Each interested party brought in their own CFI, but they could not agree as to the origin of the fire. At that point GEI was brought in.

The vehicle sustained a burn to near completion. Most of the combustibles in the interior, exterior, and the engine compartment were consumed by the fire. Large aftermarket twenty-inch diameter wheels were found on the vehicle mounted with aftermarket wide tires, a navigation system and sound system.

A large amount of drywall and insulation material was found inside the vehicle. This was fire debris from the garage where the vehicle burned. The front of the vehicle had been cleared to accommodate the preliminary inspection. The front seats had moved to their full back position, most likely during the fire. The remains of magazines and clothes were found behind the right front passenger’s seat. A lightly burned umbrella was found hooked on wires beneath the driver’s seat.

With possible spoliation from the previous inspection combined with the vehicle being too badly burned led to the conclusion that it is not possible to determine with absolute certainty the cause and origin of the fire. However, the fire appeared to have started in the left front interior of the vehicle.

The engine compartment was heavily fire damaged. All of the rubber, plastic, and light aluminum components of the engine compartment were consumed. Our expert examined the fuel injection system, the power steering system, the air conditioning system, the automatic transmission system, and the engine compartment electrical system. The battery was consumed; the alternator was heavily fire damaged and seized. The engine compartment fuse box was consumed. No short-circuits or other pre-fire problems were found to the battery cables or the engine compartment wiring harness.

The recall was for a possible incorrectly routed electrical wiring loom, under the drivers seat. Some wiring harnesses lacked a particular plastic fastener that secured the wire loom from, over time, drooping down into the path of the frame of the seat, as it moved forward and backward due to the seat position requirements of different drivers. The concern was that over time, the wire insulation would be rubbed off, and eventually short-circuit. The manufacturer provided a replacement section of wiring that would be safely out of harms way, due to its special fasteners, when the seat was advanced and retracted.

The recall notice instructions to the dealer technicians were very explicit in warning where not to route the wires. In particular, it said, “CAUTION: Do NOT route the lumbar adjustment control harness between the seat lifter bar and the metal seat pan.”

Our expert carefully examined this area and found the wires to be precisely there. During the recall service, the wire loom was misrouted between the driver’s seat lifter bar and the metal seat pan. This action was specifically warned against in the service procedure to satisfy the recall. Additionally, the driver was a tall man and had moved the seat to the farthest back seat position. This pinched the wires, rubbing the insulation off as he drove home. Once the exposed wiring made contact with the seat tray, the wires short-circuited and generated sufficient heat to melt the wiring insulation and ignite the fire. The fire then progressed upward in the areas of available fuel. This was not a circuit that turned off with the engine-it was always “hot”. Hot enough to nearly burn down the house.