Sounds like when they backfilled the inside of the garage they didn't compact the fill up against the deeper house foundation (frost walls on the garage). Over time the in & out of the vehicles would cause it to settle. Mudjacking or Pressure grouting could cause the foundation of the house to crack rather than lift the existing slab. As you have already found out - concrete is great under pressure but lousy under tension - Mudjacking against the foundation would put the foundation under tension.
I wouldn't consider it a structural defect, more of a nuisance. If it doesn't bother you that much and isn't a hazard, leave it.
__________________
Some guys they just give up living
And start dying little by little, piece by piece,
Some guys come home from work and wash up,
And go racin' in the street.
Bruce Springsteen - Racing In The Street - 1978
|