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Raising a home to BFE or DFE

jar546

Chief Cook & Bottlewasher
Joined
Oct 16, 2009
Messages
8,521
Location
Palm Beach County Florida
Homes on basements, crawlspaces, piers, etc. are for the most part, pretty straightforward to raise them, especially stick built homes.

But what about an existing slab on grade, slab on grade with masonry exterior walls?

Better yet, what about a slab on grade with concrete pilings, and monolithic poured grade beams?
 

atvjoel

Registered User
Joined
Aug 1, 2021
Messages
44
Location
Alaska
Homes on basements, crawlspaces, piers, etc. are for the most part, pretty straightforward to raise them, especially stick built homes.

But what about an existing slab on grade, slab on grade with masonry exterior walls?

Better yet, what about a slab on grade with concrete pilings, and monolithic poured grade beams?
I am actually a land surveyor by trade. You can pull FEMA FIRM maps and will specify the BFE if you are in a zone with a specified BFE. Be aware that some local communities have their own BFEs that supersede FEMA. You can also interpolate if you are in between contours.
 

jar546

Chief Cook & Bottlewasher
Joined
Oct 16, 2009
Messages
8,521
Location
Palm Beach County Florida
I am actually a land surveyor by trade. You can pull FEMA FIRM maps and will specify the BFE if you are in a zone with a specified BFE. Be aware that some local communities have their own BFEs that supersede FEMA. You can also interpolate if you are in between contours.
And most counties that have their act together provide a digital version for consistency and accuracy.
Screen Shot 2021-09-14 at 07.42.23.png
 

atvjoel

Registered User
Joined
Aug 1, 2021
Messages
44
Location
Alaska
And most counties that have their act together provide a digital version for consistency and accuracy.
View attachment 8226
Some zones are "base flood depth" and not BFE. The good thing is if you are in certain zones and your home is above the BFE then you can qualify for a LOMA. Unfortunately you have to keep in mind if you build your home and the floor is above the BFE, they still count the crawl space elevation on their calculations for flood insurance. If your crawl space is below the BFE and finish floor above then I dont think you can qualify for a LOMA. Not sure how insurance side works but i had this all the time where FF above the BFE and they get railed by insurance companies. Needless to say, build your stem wall bigger if you build a new home and get the FF and crawl space above the BFE. As surveyors you have to measure down from the FF to dirt underneath the crawl space unless of course its a slab.
 

atvjoel

Registered User
Joined
Aug 1, 2021
Messages
44
Location
Alaska
Some zones are "base flood depth" and not BFE. The good thing is if you are in certain zones and your home is above the BFE then you can qualify for a LOMA. Unfortunately you have to keep in mind if you build your home and the floor is above the BFE, they still count the crawl space elevation on their calculations for flood insurance. If your crawl space is below the BFE and finish floor above then I dont think you can qualify for a LOMA. Not sure how insurance side works but i had this all the time where FF above the BFE and they get railed by insurance companies. Needless to say, build your stem wall bigger if you build a new home and get the FF and crawl space above the BFE. As surveyors you have to measure down from the FF to dirt underneath the crawl space unless of course its a slab.
Meant to say they get railed when BFE above and crawl space below BFE. But maybe that was just them complaining I dont know. Best is to be where both crawl space AND FF are above BFE that is most ideal
 

atvjoel

Registered User
Joined
Aug 1, 2021
Messages
44
Location
Alaska
If your crawl space, FF, and adjacent grade is above the BFE it is wise just to get a LOMA.
 
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