There's a single family residence here in Norman, build around 1915, that occupies a portion of a FEMA designated floodway. It is pricey property and within a historic preservation district. It flooded about a year ago and became uninhabited. Building codes require that a derelict structure within the floodway be demolished. The owners are willing to spend a butt-load to retain the structure.
The owners have tentatively hammered an agreement out with FEMA and the local municipal intelligence to rai$e the structure (approx. 3') to place it above the BFE, as long as the original 'footprint' is not enlarged, since it still occupies the floodway.
Here's the fly in the ointment...the engineer was proposing a 'slab-on-grade' construction. The city now says they won't allow that due to the fact that fill would have to be brought in to the site.
I don't technically see a problem with that design as long as the 'fill' was within the footprint limits of the original structure...but I'm not an engineer, jes' a simple old surveyor. Has anybody else ran into anything similar? What was the outcome?
There is a rule regarding floodways that you can not place any obstructions to the flow of water, so I think the engineer is right if he is saying you can not fill (or even build stem walls), it has to be supported by pilings, like a building type 5. I had a lady that wanted to build a new house (actually, it was a manufactured home) in a flood way, and she was told she would be allowed to as long as she raised the "trailer" on pilings.
FWIW, if the house was damaged by flood (and they carried flood insurance) there is a federal grant program available to elevate houses. You might want to mention that to the clients to see if they qualify.
They've tentatively approved a permit for a "new" stem-wall, 3 feet higher than the old one. It just can't be any bigger than the old foundation. No piles.
I just can't see what it matters whether it's crawl-space or not, hydraulically speaking.
here is one that our company engineered- in the floodplain, not flood way. this picture was taken right before the "lift"
fema helped pay for this too.
Thats one hell of a lift
What Is The First Floor Made Of ?
I do not see a need for a slab.
Because it already blocks the floodway, a concrete basement can be raised that has no openings. Fill inside that wall is inconsequential to further blocking the floodway, but why aggravate the local municipality?
However, flood openings beneath the home would not be a deal breaker for me.
I have seen more than 1 story lifts along the Delaware River.
Paul in PA
first floor is..
wood subfloor on joist with about 12" of crawlspace. I guess now it will probably remain, with about 4' of crawlspace after the "hoist".
Encourage Them To Get Any Wood 2' Above Flood
And any equipment.
Paul in PA