Comment by mschuster91
2 days ago
> Or in Florida's case, mandate hurricane ties on timber homes so they can't lift off their slabs.
That doesn't mitigate much. The mass of a paper and matchsticks "house" just isn't enough to resist it getting torn apart - if not by the wind, then by debris.
The only kind of structure able to survive a dead-on hit is steel bar reinforced concrete or very, very solidly built brick-and-mortar. But that is expensive to build.
> The only kind of structure able to survive a dead-on hit...
That isn't the goal, because the eyewall of a Cat 5 is minuscule in footprint compared to the surrounding wind bands.
Consequently, most houses are going to have to deal with those winds, for which timber bolted to slab + properly secured to roof is perfectly valid.
It's uneconomical to hurricane-proof all housing in Florida.
It's entirely possible (and has largely been done) to mitigate the bulk of hurricane wind impact (the lesser standard) for all housing in Florida.
> It's uneconomical to hurricane-proof all housing in Florida.
Given the yearly news about record breaking destruction... I'd say it is uneconomical to build in Florida at all. The only thing keeping some regions (in addition to FL and other hurricane hotspots, add California for fires and potentially earthquakes) afloat is politicians bribing populations by promising government bailouts or by forcing insurance companies to offer coverage by law even if it is extremely expensive.
The amount of waste and human suffering generated because of these perverse incentives is staggering.
The news tends to exaggerate a bit (quite a bit) for effect. Where the storm hits is devastating, but a mile away can be basically fine. So percentage wise very little of Florida gets destroyed, but of the part that gets flattened, it may be entirely destroyed. Same thing can happen periodically near virtually any body of water or stream. But hurricanes are something that can be observed and predicted in advance instead of being out of nowhere like flooding
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Explain to the class where the water is gonna get all that momentum from. Florida is flat.
The storm surge goes up (and a whole bunch of water falls on top of it). The storm surge goes down. This isn't some river bursting it's banks.
Between the requirements imposed by needing to resist hurricane winds and the slab ties it's "good enough" that there's a 99.9999% chance the building will stay on it's foundation long enough for something else to be the problem.
> The storm surge goes up (and a whole bunch of water falls on top of it). The storm surge goes down. This isn't some river bursting it's banks.
FEMA has a flood rating specifically for exactly this situation: V. They have this because it carries additional hazards beyond normal flooding seen with storms.
> Coastal areas with a 1% or greater chance of flooding and an additional hazard associated with storm waves. These areas have a 26% chance of flooding over the life of a 30‐year mortgage.
And here's a video about researchers at the Oregon State University's Wave Lab studying this exact thing:
https://www.youtube.com/watch?v=-2HSFJOzQQ8
Once again, this sort of reddit-esque penchant for projecting general guidance and engineering standards into specific situations misses the mark.
Someone in a subdivision that's a few miles inland with a mangrove swamp between it and the ocean anyway has to care about New Orleans style flooding, not "what sea state is my picture window rated for" flooding.
Like there's a reason that Florida building code just says tie it down and call it good. It's just not necessary nor economically worthwhile to try and make structures shrug off the surf. Sure, literally on the coast type stuff will get rekt (most of that stuff is concrete now though) but the average modular home subdivision doesn't need special requirements above and beyond what it takes to shrug off the wind.
When it comes to wind loading the code is basically a fight between evil civil engineers who want the state jackboot to force you to buy their service and the hardware makers (Simpson and the like) who'd prefer you reference a conservatively pre-computed table and install that much of their hardware.
There are many reasons to shit on Florida but their building code is pretty top notch (and this makes it expensive but everything has tradeoffs).
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If people are going to build cheap houses, it makes sense to spend a little bit more on adding the hurricane ties (it's not like they're expensive or difficult to use). It might not be perfect, but it's surely better than just relying on gravity.
Do they not bolt the house to the slab in Florida? This is a main part of the inspection in Texas
They do. One req is continuous tension using approved connectors from roof down to slab.