(August 30, 2017 at 11:37 pm)Tres Leches Wrote:

(August 30, 2017 at 11:21 pm)Wyrd of Gawd Wrote: Do houses get crushed from water pressure in floods?   If you could seal the exterior would the house suffer any damage?

Your idea of a sealed up house is puzzling. Most homeowners like to have windows and most homes also have vents that lead to the outside.

-Teresa

What I'm saying is that in the event of a forecasted hurricane it should be possible to seal up the exterior of a house to keep out the flood waters.  Once that's done then the homeowner can go to a shelter until the flood waters recede and then unseal his house, which may be dry if he did a good job of sealing it up.

When I lived in Southern Florida, we all had stuff ready to seal everything up before going to a shelter. That comment isn't so off base. It's a thing.

(August 30, 2017 at 10:37 pm)Wyrd of Gawd Wrote: If a house was properly designed it should be possible to easily wrap and seal the exterior to keep out flood waters.  

Depending on the site and the type of house construction in might be possible to wrap and seal an existing house if you had enough time and the proper materials.

Flood waters contain much more than water.  There is all sorts of debris which can punch through a wall.

(August 30, 2017 at 6:51 pm)Thumpalumpacus Wrote: NPR is reporting 17 deaths in Houston, and a chemical plant at risk of exploding due to no way to cool the volatile products stored onsite. Two dams have been opened by ACoE to prevent failure.

Those poor folk aren't out of the woods yet ... and East Texas/Louisiana are getting hit as I type.

This is so sad.

Difficult to imagine Houston with one meter of water.
No argument about how awful that is...but..at the same time India and Bangladesh are under monsoon floods. More than 1200 dead a few millions people evacuated.
British and U.S TV start talking about it, French...zero

This is getting to depressing to continuously watch. Going to limit to just the nightly news.

Hard to imagine living thru that, and this is only the beginning of recovery.

(August 31, 2017 at 1:51 am)Minimalist Wrote:

(August 30, 2017 at 10:37 pm)Wyrd of Gawd Wrote: If a house was properly designed it should be possible to easily wrap and seal the exterior to keep out flood waters.  

Depending on the site and the type of house construction in might be possible to wrap and seal an existing house if you had enough time and the proper materials.

Flood waters contain much more than water.  There is all sorts of debris which can punch through a wall.

Not to mention the deseases that contaminated flood water can bring with it.

(August 31, 2017 at 10:08 am)mh.brewer Wrote: This is getting to depressing to continuously watch. Going to limit to just the nightly news.

Hard to imagine living thru that, and this is only the beginning of recovery.

Indeed.

We had water for 103 days here, in 2011.  Couldn't even start recovery till the damn water receded.  And since the flooding went on for so long, there was a tremendous amount of things installed for the flood that had to be removed first.  Like at the airport in Omaha; while protected by a levee, ground water was rising and threatening to swamp the place so pumps were installed, they all had to come out when the water went down.  Also had temporary sand bag walls installed and miles of dikes and levees that were built.

Turns out a sand bag that has been wet is a problem to get rid of, they get nasty and some care must be taken.

And the water also brought in and moved around all kinds of debris.  Railroad ties were floating around and left haphazardly, items that floated were moved, wind moved things around on the impounded water too.

With the longer warning time, at least most vehicles were moved out of the flood area, Texas, with up to 1/2 a million ruined cars to deal with is a huge issue we were spared.

(August 30, 2017 at 10:37 pm)Wyrd of Gawd Wrote: If a house was properly designed it should be possible to easily wrap and seal the exterior to keep out flood waters.  

Depending on the site and the type of house construction in might be possible to wrap and seal an existing house if you had enough time and the proper materials.

What, like this?

(August 30, 2017 at 11:21 pm)Wyrd of Gawd Wrote: Do houses get crushed from water pressure in floods?   If you could seal the exterior would the house suffer any damage?

YES.





People underestimate the power of water.

Think of it this way: If you're inside a car that's surrounded by water up to the windows while the interior of the car is (relatively) dry, you'll have a hell of a time pushing the door open to escape because of the pressure differential between the interior and exterior of the car door.  BUT if you allow the car interior to flood, you equalize the pressure on both sides of the door and you'll be able to open the door to get out.  And that's not even talking about whether the car has been physically picked up by the floodwaters and washed away while you're trying to escape.

A house completely sealed off from flood water intrusion would have a similar principle going on: completely sealing it off from water intrusion means the pressure exerted by the water outside can build up until the structural components holding the house to its foundation fail and the house can be washed away.  If water is allowed in it can reduce the pressure on those structural components and reduce the risk of the house being completely lost.  The pressures we're talking about, though, have a lot to do with how strong a current there is and that can vary.  Houses nearer to rivers, creeks, aquaducts, spillways and the like are at a higher risk than those further away where the currents would be weaker.

(August 30, 2017 at 11:39 pm)vorlon13 Wrote: Why are dams so sturdy ??

Same principle.

Remember, though, that dams are specifically engineered to resist the hydrostatic pressure of the water they are holding in their reservoirs.  Houses aren't built like that.  Houses are engineered with static loads in mind and where dynamic loads are considered it's usually wind and earthquakes that drive the design load, not water.  I have never heard of a developer who built a neighborhood where they engineered all the houses to resist being torn from their foundations by floodwaters.

(August 31, 2017 at 1:00 am)J a c k Wrote: When I lived in Southern Florida, we all had stuff ready to seal everything up before going to a shelter. That comment isn't so off base. It's a thing.

It's a thing, but retrofitting a house to be flood-proof is difficult and expensive.  It's much easier to board up a house to prevent wind/debris damage than it is to prevent 3+ feet of water flooding you out.

We had a "100 year flood" of the Meramac River back in '08. Only a railroad line kept it out of my back yard, ~7,000 feet from the usual banks of the river. When it was over FEMA paid to jack up all the houses by ten feet. This was chosen because the waters would cross the tracks at eight feet.

I wonder how much it would cost to jack up all those houses.

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Most houses in Texas are wooden structures. Six feet of water will force itself through them readily.