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An addition and substantial improvement

jar546

jar546

CBO
Joined
Oct 16, 2009
Messages
12,805
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Not where I really want to be
We all know that an addition to a home in the special flood hazard area must comply with the requirements under your floodplain ordinance.

At what point, however do you consider an addition as a trigger to upgrade the rest of the house if no other work is planned inside the house other than attaching the addition?
 
I don't know the answer but some jurisdictions will cite the 50% rule (ie: replace 50% of roof or siding and you need to replace all of it to conform to class A in the fire zones), or recently I hit their threshold of 1000 sq ft addition which triggered fire sprinklers throughout the whole house. We applied for an expensive AMMR which allowed fire sprinklers in only the addition (as opposed to the whole house). The most frustrating thing I learned is that everyone has their own definition of floor area.....the energy folks have their definition, the fire folks have theirs (called "fire area"), the building code floor area is based on height for habitable space, etc..... and none of them align.
 
If you add square footage, you expose yourself to more flood flow, thereby putting more stress on the existing construction.
 
Jar, I know this question was asked a while ago but didn't see many replies so I figured I would throw my 2 cents in. The way its done in my jurisdiction is by a 50% rule which is considered substantial improvement...using your question as the example, if the total estimated cost of all work including painting, appliances, labor and materials for building the addition and all subs ect... equals or exceeds 50% of the value (appraised or assessed) of just the structure the addition is being attached to then the entire house must be raised to BFE plus 1 foot fretboard. It can be a real pain especially because alot of people dont do their research before planning the project, hiring everyone, getting the plans drawn up, and applying for permits
 
For purposes of the Natoinal Flood Insurance Program the FEMA Coastal Construction Manual says:
SUBSTANTIAL IMPROVEMENT: Improvement of a building (such as reconstruction, rehabilitation, or addition) is considered a substantial improvement if its cost equals or exceeds 50 percent of the market value of the building before the start of construction of the improvement.

 
Paul Sweet said:
For purposes of the Natoinal Flood Insurance Program the FEMA Coastal Construction Manual says:
SUBSTANTIAL IMPROVEMENT: Improvement of a building (such as reconstruction, rehabilitation, or addition) is considered a substantial improvement if its cost equals or exceeds 50 percent of the market value of the building before the start of construction of the improvement.

Click to expand...
I believe that this is the correct answer. Our municipal code, as I believe most jurisdictions will similarly do, is worded to match the FEMA language. Otherwise, your jurisdiction may find themselves crosswise with FEMA and end up on the naughty list that kicks you out of the FEMA insurance program.
 
Agreed on the 50% rule along with an additional "factor" in the equation which I have found varies town by town. , at least here in NJ. Had a project years ago whereby homeowner wanted to add second level to small ranch house. House had basement and had no issues or flooding with Hurricane Sandy. If we designed what he wanted, we would have had to fill in the basement. We did the math and worked backwards (scaled down the scope of work) so that the construction cost did not exceed the threshold so that he could keep his basement. A year later he applied for new permit for balance of work (call it phase 2) and he is happy.

I am not a fan of loopholes but I do like happy clients. I explained to the Floodplain Manager from day 1 exactly what our strategy was and he said no problem.
 
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