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Thread: Hurricane-proof homes - the science & engineering of surviving 155 mph winds

  1. #1
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    Exclamation Hurricane-proof homes - the science & engineering of surviving 155 mph winds

    Two articles covering the very few houses that survived directs hits by Hurricane Michael at its worst.

    ===========

    https://www.scientificamerican.com/a...to-adaptation/

    The Buildings That Survived Michael Hold the Key to Adaptation
    Houses that survived were mostly built after Florida’s stringent building code was passed

    Daniel Cusick, E&E News on October 15, 2018

    [[Article has some photos of homes that made it and some that did not.]]

    ==============

    https://6abc.com/beach-home-survives...rvive/4491085/

    Beach home survives storm nearly untouched: 'We intended to build it to survive'

    [[Article has amazing photo of the big beach house that did not go down.]]

    When Category 4 Michael made landfall at Mexico Beach Wednesday with winds around 155 mph, Lackey was home in Tennessee, "nauseated" as he monitored the house security camera, watching footage of the winds and debris whipping by. Lackey wasn't confident the home would survive, afraid he would lose the roof at any moment. "I was watching the corner of the roof buck like an airplane wing. And I was watching the air pass by with debris in it about the speed of which you'd expect to see in an airplane," he said. For Lackey and his uncle, the goal during construction just last year was to go "overboard to preserve the structure." He said they often went the extra mile to add more concrete -- especially in corners. Making small accommodations as they went, he said they often "went one step further" beyond the building codes, like when they added 1-foot thick concrete walls as well as steel cables to hold the roof steady. They also built the ground floor out of tall pilings, with the house elevated above it, to create a ground floor structure intended to give way with massive storm surge if necessary -- and "sure enough it did," he said.

  2. #2
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    I saw a fair bit of the metal roofing blow off
    living in the ANDREW eye-wall path
    and needing a new roof currently

    I am thinking 3 layers of 1/2 plywood screwed and glued [add two to the existing single nailed layer]
    local code requires tar-paper nails lots of nail holes [i see no point to] and something else shingles , tile , or metal

    I would like to do something less likely to blow off at 150++
    and currently favor cement reinforced with steel but that is ''not in the codebook'' like a concrete boat hull
    nor is the bare ply roof painted but not tar papered ''legal''
    a engineering stamped plan is required if I do the concrete/steel poured roof

  3. #3
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    Quote Originally Posted by nota View Post
    I saw a fair bit of the metal roofing blow off
    living in the ANDREW eye-wall path
    and needing a new roof currently

    I am thinking 3 layers of 1/2 plywood screwed and glued [add two to the existing single nailed layer]
    local code requires tar-paper nails lots of nail holes [i see no point to] and something else shingles , tile , or metal

    I would like to do something less likely to blow off at 150++
    and currently favor cement reinforced with steel but that is ''not in the codebook'' like a concrete boat hull
    nor is the bare ply roof painted but not tar papered ''legal''
    a engineering stamped plan is required if I do the concrete/steel poured roof
    I am sure you also consider more fasteners as well as a basically heavier roof. That implies more rafters under the roof and those rafters tied down to the ground with bolts and ties. The forces of lift at 155 mph are rising with the square and the gusts get stronger too. So i would concentrate on more tie downs per area, at least double the previous code, rather than just heavier skin. An aircraft skin is just thin metal but tied down to beams to withstand those kinds of lift forces.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Recent news report on a coast-area ("low country") man who is building "Category 5" homes for his family. Text does not have a lot of detail, but it includes a video with more information.

    https://www.live5news.com/2018/10/15...e-summerville/

    South Carolina (where I live in the "upstate", near the Appalachians, northwest corner of the state) has been hit twice this year by hurricanes but took a direct coastal hit from Hugo a few decades ago. Some damage in Charleston still not repaired.
    Last edited by Roger E. Moore; 2018-Oct-18 at 01:25 PM.

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    Curiously, there is a science-fiction angle to this. In Larry Niven's Known Space series, the human-colonized world known as We Made It undergoes severe super-hurricane winds at times because of its axial tilt and orbit around Procyon. Most humans live underground.

    Can't live underground in coastal hurricane country here, too much water comes in. Gotta build aboveground to last forever.

    https://en.wikipedia.org/wiki/Known_Space#Locations

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    Silly me, never thought to go to... WIKIPEDIA

    https://en.wikipedia.org/wiki/Hurricane-proof_building

    This gets more interesting all the time. Has a number of diagrams, many photos.

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    Having witnessed what hurricanes can do to my parents house located adjacent to the beach, I thought the following might be an economic design....

    Step 1.jpg
    Step 2.jpg
    Step 3.jpg
    Step 4.jpg
    We know time flies, we just can't see its wings.

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    Step 5.jpg
    Step 5c.jpg
    Step 5d.jpg
    Final bldg. with a gentle roof slope to allow a mower to mow the grass.
    Final bldg.jpg

    Being a free-standing building allows for a terrific range of construction within the building, be it home or commercial.
    We know time flies, we just can't see its wings.

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    Maybe this is naive, but if you use reinforced concrete (like the building I live in) it will be pretty resistant to typhoons or hurricanes. Is it because of the cost or the aesthetics?


    Sent from my iPhone using Tapatalk
    As above, so below

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    Quote Originally Posted by Jens View Post
    Maybe this is naive, but if you use reinforced concrete (like the building I live in) it will be pretty resistant to typhoons or hurricanes. Is it because of the cost or the aesthetics?
    Try low wind resistance and exceptional strength. I live near a large seaway entrance and all of the steel/fiberglass/wood boats tend to be broken up due to waves while ferro-cement ones have had to be destroyed as they tend to become navigation hazards.

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    Quote Originally Posted by LaurieAG View Post
    Try low wind resistance and exceptional strength. I live near a large seaway entrance and all of the steel/fiberglass/wood boats tend to be broken up due to waves while ferro-cement ones have had to be destroyed as they tend to become navigation hazards.
    Sorry, the question I meant to ask is, why don't people build their houses in Florida out of ferro-cement, since they would surely resist hurricanes?
    As above, so below

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    Quote Originally Posted by Jens View Post
    Sorry, the question I meant to ask is, why don't people build their houses in Florida out of ferro-cement, since they would surely resist hurricanes?
    Cost. A concrete building is more expensive than metal or traditional wood structures. I work in a concrete tilt-wall building but the company's new building is metal due to cost savings.

    The concrete design above eliminates a number of cost factors including A/C costs since the roof is about two-feet thick in material, like an above-ground cave, sorta. The forming cost are greatly reduced since only ~ 8" form boards are needed for the slab-roof structure, excluding the parapet. Even the parapet likely can be slipformed by a machine with no form costs, though it may be as cheap to form it with the crew already there. No crane is needed and ready-mix pump trucks are now typically the most economic way to pour any large slab.

    No one, to my knowledge, has put numbers to this as I'm not in this business but I was involved in planning the new building. My hope was to get one of the giant concrete companies to get involved and perhaps get grant money to do it, but they were too busy at the time.

    The savings with the use of dirt may only work when the facility is on perhaps about 5 acres of land to make use of the material. Since retaining ponds are now required for commercial sites, a lot of material need not be hauled onto the site if the site is in the hill country and lacks top soil for landscaping.

    I don't know the annual insurance cost difference but that could be one of the big cost advantages as well.

    This idea goes back over 20 years ago and an environmentalist friend took it to friends in California who liked it. That's as far as it ever got though, again, I'm just playing as an "idea guy" not an active promoter- just pouring water into the trough, not ringing any bell.
    Last edited by George; 2018-Oct-19 at 02:23 PM.
    We know time flies, we just can't see its wings.

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    Quote Originally Posted by LaurieAG View Post
    Try low wind resistance and exceptional strength. I live near a large seaway entrance and all of the steel/fiberglass/wood boats tend to be broken up due to waves while ferro-cement ones have had to be destroyed as they tend to become navigation hazards.
    Why are these navigation hazards? I traveled to a ferro-cement sailboat builder in S. Texas with my sailboat-loving father many decades ago and learned that these boats get stronger (perhaps just harder?) with time. He came very close to buying one.
    We know time flies, we just can't see its wings.

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    Definitely costs. To build a highly hurricane resistant home with reinforced concrete walls and roof is about twice as expensive as the typical framed or cmu walls with wood truss roof construction that homes in the US are typically built of. Impact rated windows and doors are also much more expensive than the typical contractor grade stuff.

    I just recently bought a new front door for our home and decided to go ahead and spring for an impact rated one so I wouldn't have to worry about covering it every time a hurricane comes along. Which is frequent where I live. One year our house spent 11 hours in the eye wall of a level 2 hurricane and then less than a month later spent 7 hours in the eye wall of a level 3. Both hurricanes stalled out right on top of us. Just last season a Cat 5 missed us by less than 100 miles.

    Anyway, for a standard size single door with a 10" side light, installed, it was approximately $3,200. I'd like to replace all of the windows, including 3 sliding glass doors, with new impact rated stuff but I'd probably have to drain a good bit of the equity I've got in the house to be able to afford it.

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    My guess they are hazards after being blown into the wrong place. They should indeed get stronger with age so long as the bond to the fibres stays strong. It's kind of interesting the glass reinforced resins eventually lose the bond and half their strength, not more. The fibers have to be treated to prevent corrosion from the cement. But as a composite material - great stuff.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    well it was a busy weekend
    a keys builder had completed a huge condo project
    and had 120 sheets of new 5/8 ply still in shipping bundles left over offered on craig's list cheap
    but I had to move it out with an older trailer and my 93 volvo 240 wagon 3000lbs a bundle/trip
    two blow out on the first trip new tyres for the second load almost home 1 1/2 block away a wheel comes off at low speed

    so my first part is done and way under budget

    next is to find a good glue not too expensive as I need to cover 1300sf twice
    epoxy would be too high cost

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    Quote Originally Posted by Jens View Post
    Sorry, the question I meant to ask is, why don't people build their houses in Florida out of ferro-cement, since they would surely resist hurricanes?
    there are a few most late 50's built
    one of the larger builders had a set of steel forms locally
    they produce a small house with few options
    they were among the few that survived ANDREW's eyewall with little problems thanks to a solid concrete roof and walls
    Edison was building some in 1910 in NJ and a few others have tryed
    the local ones were small hard to expand or even run a/c ducts

    most local homes are CBS walls with a standard wood truss roof covered with a single layer of plywood 1/2''
    the trusses are tied to the CBS wall caps with steel straps but the plywood is nailed on
    then a tar paper nailed on with shingles nailed on top
    or tile or metal roofing only the sheet metal is screwed down and all leave the plywood full of nail holes

    still amazed to see million plus dollar huge water front homes built with the single ply 1/2'' roof

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    Fascinating little piece on why people don't buy disaster-proof homes, even if the disaster is right on top of them (e.g., they live in dry sagebrush but refuse to buy a fireproof home). Also good for news on disaster-proof building.


    http://fortune.com/2018/06/20/hurricane-proof-homes/

    Hurricane-Proof Homes Exist — Why Isn't Anyone Buying Them?

    By Bloomberg, June 20, 2018

    In a private waterfront resort on the northern tip of Key Largo, nestled between tropical forest and the Caribbean, Eric Soulavy is marketing luxury for the age of climate change: Coastal homes that are all but hurricane proof. The Florida-based developer is finishing a three-story condominium project with overlapping defenses, a hydrological Fort Knox where prices start at $5 million for a four-bedroom apartment. The 27 concrete-encased units are perched 13 feet above ground with windows that can withstand 174 mile-per-hour winds. Flood pumps in the parking garage can push 20,000 gallons of water per hour 65 feet underground, fueled by a generator so large it required its own building.

    “I come from the luxury world,” Soulavy said on a recent afternoon, as he walked around the development in loafers and an exceedingly good tan. “When you’re dealing with these types of buyers, you can’t underestimate anything.”

    Architects and engineers are devising increasingly effective protections against extreme weather — and not all of them as elaborate or costly as the Key Largo project. They’re designing homes that can deflect hurricane winds, rise with the flood waters and survive wildfires. But those innovations have been slow to spread, remaining largely the preserve of homeowners who are very wealthy, unusually safety conscious or just plain quirky.

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    on a sailing board [anarchy] a suggestion was made to use a rigging cable to tie down the roof peak and sides
    with a steel V shape on the peak held down with the cables to ground anchors

    as I plan a steel panel roof on my house with a single ridge peak I think a steel bar or U channel to connect to the peak inverted V steel cap welded in place
    and continue the steel down to concrete slab foundation and simply bend the steel under the foundation a pour a block to hold it in place [filling the hole dug to place the steel]
    only at the 4 corners as the damage tends to start there or the peak
    I am guessing 1/4 '' steel galvanized as the V or U shapes would be a match for wind lifting and not too heavy as it would be directly over the CBS walls except the ridge peak cap

    you guys see the last one that grew to cat 1 to cat 5 in 24 hours ?

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    got the steel 5v roofing way more then I need 104 sheets 21 ft long cheap off an craig's list ad

    got to love change orders and we no longer need this new stock [they went with standing seam]

    I only need 44 plus 15 for the garage

    so edges will be tripled and every other sheet doubled in the middle of the roof plus the peak will be over lapped 5 ft

    found steel pipe 6'' dia 0.28'' thick near 1/4'' galvanized at 18 lbs a foot so cut in 1/3 slices will be 6 lbs a foot and cover the peak

    then the cap will be welded to 1/4 by 4'' steel channel over the CBS walls only and down to the slab as hurricane straps for the edges

    can stick in some 4x4's to support the roof peak cap steel to spread the loads

    so I need to quickly pick a glue type and some other glue/filler for the plywood voids

    and or an other to sealent for the seams steel 5v panels and glue to stick the extra layers together

    would the wood floor glue be a good void filler for the plywood ?

    are there clone/copys of 5200 that are cheaper/similar or an other product to seal the steel panels together as I will need a lot of tubes for the 5 v steel roofing

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    no new comments in a week bump ?

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    https://www.deltechomes.com/learn-mo...ne-resistance/

    Corporate website showing an assortment of hurricane-proof homes, different shapes but most of them pole-elevated, octagonal/rounded. "Survivor" photos are intriguing, made it through storm surge.

    Good place for ideas.

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    agree with most of their plan
    using 5 core 5/8 plywood tripled
    using the steel roofing doubled
    can't change the shape eazy but agree round is better
    and do not need pilings as I am on a ridge out of the flood/surge area [dry in andrew cat 5 in 92]
    so wind not water loads only needed here

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    This is how NOT to rebuild after a hurricane.

    https://phys.org/news/2018-12-houses...lt-bigger.html

    Houses in hurricane strike zones are built back bigger
    December 10, 2018, University of Southampton

    A study of hurricane-hit areas of the United States has revealed a trend of larger homes being built to replace smaller ones in the years following a storm. The research, led by the University of Southampton (UK) and published in the journal Nature Sustainability, shows that the sizes of new homes constructed after a hurricane often dwarf the sizes of those lost. Lead researcher Dr. Eli Lazarus, of the School of Geography and Environmental Science at the University of Southampton, says: "Our findings highlight a 'building back bigger' trend in zones known to be prone to damage from extreme wind conditions and storm surge flooding. This practice creates an intensification of coastal risk—through increased, high-value property being exposed to major damage or destruction."

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    pulled my permits and started my tear off

    this was a post hurricane ANDREW [cat 5 eyewall strike here] rush ** roof job
    done long before I bought the house

    they left part of the front lower roof as t&g 1’’ planks butted up to 1/2 plywood with NO transition
    guess where it leaked !!!
    so all the t&g is coming off down to the rafters
    some rot on some rafters so they will be sister-ed one 2x6 on the 4ft and double on the 8’s
    after the bad parts are cut out
    no point in a strong roof deck on weak beams
    beams sister-ed will be hurricane strapped to code with top-cons screws into the concrete wall cap

    after that we need a peel+stick layer that will self seal the nails and screws [for the metat 5v top]

    WHAT DO YOU GUYS LIKE FOR A STRONGER THEN PAPER BASE LAYER THAT SELF SEALS ?

    then a fire proof layer top cap required by the new code here

    then the 5v metal roofing lapped and doubled on every other sheet

    and after all the standard roofing an added set of steel 1/4 thick channel over the CBS walls welded to a 1/4’’ thick 1/3 of a steel pipe all galvanized and painted and tucked under the house slab to anchor with concrete to fill the hole under the slab

    I dare wind alone to move that roof
    and even impacts should not be too bad

    then we start on the tripled plywood deck screwed and glued with wood flooring glue


    does anyone make a fireproof SELF-SEALING CAP SHEET
    or is the non-fire rated SHEETS the only SELF-SEALING products out there ?
    __________________

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    banging and scraping has let up I think the last of the tear/off is done

    we did the larger front 1/2 with know problems [bad t&g planks] sister-ed a bunch of beams added straps
    and layed down 2 new layers of 5/8 plywood over the whole 1/2 roof screwed and glued

    then started on the back now striped to the original plywood 1/2'' fist layer
    and my crew of neighbors wants me to go back to the store to get pipe boots and drip strips

    just to make the whole ordeal more fun the wife caught the flu and got a bad infection from her crones meds suppression and had to be hospitalized but is recovering
    and gave me the flu also as soon as the sniffles started I got a flu shot and anti-viral meds and hope to avoid the worst of the flu but can't work so just buy stuff and drive it back
    Last edited by nota; 2019-Jan-07 at 06:28 PM.

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    Love to see some photos of your work if possible. Thanks!

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    Considering the problems encountered with severe hurricane strike for domiciles, surely we should consider the ferro-cement dome.
    This would be a shallow dome of perhaps 40 % of the upper hemisphere. It is labor intensive, but if strength in the presence of
    150+ MPH , from many directions (as the hurricane moves) this design begins to offer promise. Providing elevation as per tidal surge isn't easy, but with sufficient piles and non-corrosive fasteners, doable. You have to ask yourself..." Do we really need to be in the tidal surge
    zone? Also, mother nature is shifting the goal posts with sea level increase.
    But as far as surviving the missiles ( posts, 2 by 4's ,pipes etc in the wind ) I should bet on ferro-cement structures. They also have the advantage that the formosa termite won't eat concrete (last I heard). It isn't cheap. To counter the potential for nicked armature material , which can corrode, perhaps the investment in non-corrosive wire is the answer for that theater.
    Certainly, we need to do things differently from the past.
    By the way: the reason I live 50 miles inland from the salt water areas I love is that I respect and fear the wrath of a full strength hurricane roaring up the east coast and slamming into Rhode Island at winds of 160 mph with gusts over 200. That is what global warming can and will do for coastal living . We must look to and design for the near future and yes, the present day . These storms visit us more frequently and with more violence than people think of when building a beautiful home. Even the three little pigs evolved in their
    architectural considerations.
    Dan
    NOTE: after reading through "all" of the posts, I see Jens and others thinking ferro-cement as well. Still, and interesting approach.
    Last edited by danscope; 2019-Jan-08 at 10:13 PM. Reason: note as read

  29. #29
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    After cyclone Tracey almost wiped out Darwin in 1974 the building regulations in the Northern territory (NT) were changed.

    Note the difference between the standard Purlin Tie and the NT Purlin Tie.

    https://the-guide.com.au/home-guide/...cts/purlin-tie


    https://the-guide.com.au/home-guide/.../purlin-tie-nt

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    well the roof is done

    go here for pictures https://talk.roofing.com/t/i-need-a-...-roof/21160/16

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