Designing a house for a client on a lake not far from the Gulf in the FL panhandle. Going to raise it on concrete piers. Guessing the engineer will call for about 24 12″D piers. The challenge at the moment is determining the height of the house. The height affects the design, which affects the cost.
They had 3.5′ of water from Hurricane Opal. Deciding if they wanna plan for (budget for) 4′ or 6′ or 8′ or 10′ surge.
The question now is, can you offer any guidance for the incremental cost of each foot of the column? Trying to give them a range of costs for moving from 4′ to 5′ to 6′ and so on. I’ve built 18″D columns 25′ high, but don’t have the perspective of a builder pricing them out. I’m guessing the rebar core will be 4 #5’s or #6’s with a belt every foot or so. Beyond that it’s all a guess at this point till we get the engineer on board.
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Speaking of columns and engineers, here’s a short story from my engineer. He got a call from a guy building a multi-story house. The engineering called out a single steel column on the main floor (with appropriate footer and ceiling attachment details) as “4 inch column, Sched 40” or some such. The “builder” was planning on using Sched 40 PVC!!!! Didn’t know the whole detail was for steel. When asked how that could support the loads, he said he was gonna fill it with concrete!
Same “builder” didn’t know what a header or a king stud was, either.
Glad it wasn’t one of my designs.
Be very, very careful out there.
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Seems to me that as the columns get taller they may have to get wider as well, due to side loading from wind/wave forces.
I don't see how there could be any way to do it other than to engineer both sizes and fully price them, or base estimates on someone's previous experience building very much similar columns to similar specs.
we have a height of 13 feet. If they got water during opal, they pretty much going have to raise floor up to 13 feet. local building inspector could tellyou.
>...base estimates on someone's previous experienceThat's why I asked here. Perhaps someone has built concrete piers 12" or 14" or 16" or 10" and figured that the incremental cost of a foot is $100 or $200 or $20 or $x or whatever. At least with the experience here I might be able to bound it to $x-$y.
not 100% on subject...
but brownbag I'm sure has a grasp on what's required for the area...
I've spent a ton of time in that area and keep up with alot of what is getting built there... and a ton comes into play when you are dealing with the sands and beach area...
I spent a 4 days watching them raise a house that would never be allowed to be built under the new codes (sited very close to the water)
they punched holes in the walls slid i-beams through and drilled holes through the slab... pushed a type of toggle bolt through the hole that was then attached to the i-beam... must have had over 100 bolts...
Ibeams on electric over hyd jacks... they raised the whole house about 12ft in the air... drove bobcats under the house... placed concrete piers and a parking slab under ythe house... they had raised the house level... so they measured down to get the exact pier heights for each pier as what was the bottom of the slab would now sit on these pier once it was lowered back onto them... they even drilled up into the slab... placed a pin in the top of the pier and lowered the house onto said pins...
very cool operation... at the time they told me it was a 60k job... but it was that or distroy the house and be left with a lot you would never be allowed to build on again... crew told me they were doing one a week and if they had more guys & equipment they had calls to do one a day....
I'd look at the space below as covered parking, pretty sure you can have walls but that they must break away in a storm...
keep us informed what you they do require
p
http://www.al.com/printer/printer.ssf?/base/news/118155367647060.xml&coll=3"Mobile County requires that Crockett's new house be at least 17 feet above sea level, which is 2 feet above the 100-year flood prediction of 15 feet. Yet if he were building a few miles away on Heron Bayou in Jackson County, Miss., his house would have to be 21 feet above sea level."
Edited 7/14/2007 11:58 am by brownbagg
Kinda like with floods along the Mississippi...what flood plain do you build for? What disasters are you trying to prevent?Do you build for a 3' flood and hope to not see 10'? Do you build for 10', having "wasted" the money if you see a max of 4' in your lifetime?The higher you build, the more the daily inconvenience of ascending that height. The lower, the greater the anxiety re storms.Pick your poison.I'm trying to gauge incremental costs so I can help them pick the least distasteful poison.While we were shooting the #### here, they picked 8'. That gets them parking, an outdoor shower, light storage via tear-away walls, and a bit more. Couldn't do that at 4'. But it also means they'll have wet feet if there's a 10' flood.They picked their poison. Now we gotta design and engineer it, get formal estimates and see how bitter that poison actually tastes.Still interested in opinions on the cost of pouring such columns...
Design the home to flood up to two feet deep -- put most storage above that level, make walls water/wave-tolerant up to that level, etc. Air conditioner & air handler in the attic or elevated somehow. Some sort of wave deflection scheme (could be incorporated into a deck/balcony) on the seaward side, to break up the energy of the waves before they hit the walls.If they get a bad storm the furniture, carpets, and appliances will be trashed, but the home will still be secure.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
That's part of the consideration at any height. There's always a threshold at which you stay dry, get minimally wet, are inconvenienced, or have catastrophic damage. Each of these has a cost, and it's that cost/benefit by which the client makes the decision. I know the spectrum of "safety" and am now seeking the spectrum of "cost".
Not an engineer nor do I play one on tv but would pilings be worth considering? ..........Suspect you may have to go pretty deep even with a bell bottom pier. Driven wood and concrete pilings seemed pretty common to me in road and bridge projects along the Gulf coast....... might be worth looking into depending on your soil conditions. No idea as to cost.