Are there regulations on building homes at the end of a runway?
The FAA has regulations on the maximum height of obstacles around a runway (page 22):


  The runway Obstacle free zone (OFZ) is a defined volume of airspace centered above the runway airspace above a surface whose elevation at any point is the same as the elevation of the nearest point on the runway centerline. The runway OFZ extends 200 feet (60 m) beyond each end of the runway.


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  The inner-approach OFZ is a defined volume of airspace centered on the approach area. ... Its width is the same as the runway OFZ and rises at a slope of 50 (horizontal) to 1 (vertical) from its beginning.