Infill lot costs are where most park underwriting falls apart before a number is ever typed
The common assumption is that an empty pad costs whatever it costs to get a home on it, and once you subtract the lot rent shortfall you are done. That is not how it works in most markets I look at. The number doing the most work is not the home cost or the transport fee, it is the time from pad activation to stabilized occupancy, because during that window you are paying debt service on a lot that is not covering itself. Say a park runs 55 lots and 9 are empty. At $400 per month per lot, that is $3,600 per month in lost revenue. If infill takes 18 months per lot averaged across the 9 pads, you are looking at $64,800 in foregone revenue that never appears as a line item in the acquisition underwriting. It just shows up later as the return that did not come. The decks I see almost always model infill as instantaneous or use a single fill-up period rather than a staggered timeline per pad, and the stagger matters because your first filled lot does not prove the second will fill on the same schedule. It proves you have one data point. The assumption underneath the whole infill thesis is local home availability, because you cannot place a home on a pad that nobody will sell you at a price that makes the lot economics work. In many markets right now the new home pipeline from manufacturers is the real constraint, and a 6 to 9 month delivery window on a new HUD-code home changes your infill math more than almost anything else in the model. What does the seller's stated infill history actually show, meaning how many of those 9 pads have been empty for less than 24 months versus longer?
