In North America, it's common for houses to have one or two garages.
Literal
North-America [in-では] 1 [of-の] house [to-に] 1 [or-ないし] 2 [of-の] garage [subject-が] exist [nominalizer-の] [topic-は] common thing is.
ないし ('or, from...to') is a formal/written connector for listing alternatives or ranges — '1 or 2,' '20 to 30.' More considered than や or the colloquial か. よくあること ('a common thing, something that happens often') is a standard hedge for 'normal, usual.'