This Content Originally Published by a land surveyor to Land Surveyors United Network
I would agree with this and it makes sense (even though that is often not a required element). Just like a home with a crawl space where the water could enter the crawlspace through foundation vents or the access, the floor of the crawlspace is not considered the LAG. What ends up getting us from time to time, is that attached stairs and deck supports count as part of the structure for the determination of the LAG for a LOMA.
FEMA LOMA Determination Requirements:
I had this discussion with a FEMA tech at the first of last year. He claimed that the LAG was the bottom of the access well to the crawl space. I could not get him to budge and the LOMA was denied.
Since then the new EC has come out with Diagram 2B. That diagram calls for the LAG at the top of the walk out. Therefore the bottom of a window well for a basement (below existing ground) is not the LAG.
We resubmitted and have successfully received a removal for last years denial.
I think it would be Diagram 2B and the Grade would be the ground, based on the Diagram in the instructions. Since the finished floor would be the controlling factor for being in or out of the flood, the LAG by the window would prevent surface water from getting into the window well (except for rainwater straight down.)