Built in 1996: Can My House Survive a Category 4 Hurricane?

[MGC]

My house in Diamondhead Mississippi went through the eastern eyewall of Katrina. The house was build in 1997. Had it not been for the 4 trees that landed on the roof the house would have survived fairly undamaged. Of course we only saw Cat-4 gusts there, but there was an extended period of hurricane force winds. The house I currently live in was build in 1947 and has survived both Camille and Katrina. It is built with real 2X4's not the new cheap lumber. I would not trust a new home to sustained Cat-4 winds.......MGC

[TheShrimper]

Dade County Pine, Southern Yellow Pine, and Yellow Pine are all one and the same. All PT lumber purchased is made out of this wood. If anyone is in the excavating business, they will attest to the fact that if an old yellow pine stump is unearthed, even after decades, you can strip a piece off and put a match to it, it will burn and burn, no matter if there is a driving rainstorm or not. The turpentine content is so great. Over here it is refered to as 'lighter knot". Now when it is lumbered, you'd best get it nailed in place in a quick fashion, as it will do what it wants, twisting ect. The older houses were framed with the full 2"x4" studs, not the 1 1/2x 3 1/2 studs we are used to buying at Home Depot. And as someone else alluded to, when dry, dont try to cut it. You'll be replacing blades as fast as you can put them in.




'

[Ptarmigan]

I don't think your house will survive. It will be badly damaged for sure. Storm surge will completely destroy it.

[Recurve]

Dade County Pine, Southern Yellow Pine, and Yellow Pine are all one and the same. All PT lumber purchased is made out of this wood. If anyone is in the excavating business, they will attest to the fact that if an old yellow pine stump is unearthed, even after decades, you can strip a piece off and put a match to it, it will burn and burn, no matter if there is a driving rainstorm or not. The turpentine content is so great. Over here it is refered to as 'lighter knot". Now when it is lumbered, you'd best get it nailed in place in a quick fashion, as it will do what it wants, twisting ect. The older houses were framed with the full 2"x4" studs, not the 1 1/2x 3 1/2 studs we are used to buying at Home Depot. And as someone else alluded to, when dry, dont try to cut it. You'll be replacing blades as fast as you can put them in.
'

Yes, 2x4 nominal and 2x4 actual lumber are different. But I think there's also some agreement that the pines that grew in deep se FL -- dade -- are unique in strength.
And today not all 2x4s are SYP, though all the PT you find is.

[wxmann_91]

As others have already stated, it will probably not.

The problem is that while your house perhaps can withstand 150 mph winds, momentum and kinetic energy account for both velocity and MASS. Air lacks that. 150 mph winds have a whole lot of power but not as much as a piece of a sign that travels at that speed. Or a branch for that matter. A piece of debris traveling at that speed could break through. From there on it would be a downhill battle. The winds would likely then destroy the structure from inside.

[DanKellFla]

Do you have a concrete roof? Otherwise, I doubt it. Also, what about your soffits? Those have turned out to be a problem form many people. I spoke to one adjuster who told me about house that had no roof damage, but the soffits failed and wind driven rain heavily damged the interior of the house.

[Dionne]

I am a carpenter. 32 years in the trades. Without personally seeing your home it is hard to judge the possibility of the structure surviving 140 mph winds. If your home has gable end roof lines it is unlikely they could withstand strong winds. If you have a full hip roof, your chances improve. Look for connectivity from the foundation through the roof line. If your home is a McMansion (cookie cutter) it is unlikely to survive the winds.

We have a home in the historic district of Hattiesburg, Mississippi. It is an old home....full dimension lumber, shear panels throughout and a full hip roof. It survived sustained 90 mph winds of Katrina. Our daughter rode out Katrina in this home while a student at USM. She told me the walls were vibrating. I am of the opinion that the home was approaching failure.

My home in Crystal Springs, Mississippi is a one level 3/2 brick veneer built on a concrete slab with gable end trusses in the roof system. Built in 1970. I seriously doubt it would survive 140 mph winds.

[Frank P]

I think you can build a house to survive Cat 4 winds, provided they are relatively short in duration... some key ingredients that can help that process

As mentioned earlier its very important that the house is not breached by wind... some things you can do in a typical stick built house to prevent that are as follows:

Windows and Doors

1. Install Armor glass... glass that will not fail even if hit with wind debris hitting it at 200 mph, costs about 600-700 for a 3X6 window. Manufacture guarantees it and states you don't have to cover with shutters... I am still covering my front windows with shutters..
2. Hurricane shutters... Dade county type approved
3. Reinforced garage doors, entry doors.., kits available

Roofing

1. All hip roofing, strap/tie every connection ....
2. Min 5/8 inch plywood roof decking... ring shanked and glued... even better, spray dense foam at all the plywood joints and rafter connections from the underside of the decking... helps prevent plywood decking from leaking if metal or shinges are blown off, and also helps secures plywood decking to rafters... if you don't want that expense, which about $2-3K (florida residents get a good discount on their home insurance if they do it), then do the same thing with glue, much cheaper and something the home owner can do..
3. Add addtional metal straps from rafters to underside of top plate of exteror wall.. strapping is cheap and something the home owner can do quite easily for a new construction project.
4. Add additional shear support for all gable roofing.
5. Plywood the soffets before finishing them... this is very critical for those homes with vinyl siding soffets... reason, siding soffets will be blown off leaving quite the breach area for winds to enter through the openings... winds will now have direct access to the attic of the house and will do one of two things... either blow all the sheet rock ceilings down, or blow off the roof decking... the second is really bad and could cause the house to fail.. not good to lose any part of your roof... to install siding sofffets they usually either nail directly to the ceiling joices or strip with 1X4s...

Walls

1. 2X6 framing
2. Strapping on every stud, not every other one as code required.
3. Strapping on window headers
4. 3/4 in plywood sheating on exterior walls for maximum shear strength (ring shanked). For raised houses have the plywood drop down below the bottom wall plate to tie into the primarly load bearing joices... bottom line, must have a continuous connection path from the bottom of the house to the top... no weak points... everything interconnected
5. Use closed cell dense foam for all wall insulation... great for sound and energy savings but even better for increasing the strength of your house, glues your walls studs and top and bottom plates to the plywood. (also either bolt or screw down your bottom toe plate).. also use dense foam if you have a raised house for flooring insulation ... about 2 times more expensive than fiberglass, many new home builders along the MS coast are using foam now
6. Use docking hardware (corner plates) to strength corners of porches. install in the front and rear corners of the porch headers... 3/8 in gav plating with gussets... comes in a variety of sizes... either thru bolts or use lag screws (1/2 in). Don't want to have any porch failures either...

these are just some of the things that I did for my new house and many of my friends are doing the same building their new homes..

but the best advise I can give any one is NOT TO BE UNDER INSURED... because if mother nature wants your house she is going to get it... and I don't care how well you build it..

[Tampa Bay Hurricane]

Thank you all for the excellent advice!! I wanna build myself a hurricane
proof home sometime down the line when I graduate from college
and get me a house...

oh also the house that is supposed to withstand cat 4 even though
it probably wouldnt is my parents house we moved here in 1996

so hopefully ill build me a domelike tornado/hurricane proof
house so I dont have to worry so much when a hurricane
comes

[Dionne]

Hey Frank P.....you should write building code standards. I only noticed one miss. When using the strapping make sure you use the appropriate nail......not an 8p or a screw but the fat teco nail.

[Frank P]

Thanks, and you are exactly right Dionne about the nails... you need to make sure you fill in every hole in the strap as well...inspectors don't like holes not nailed... actually they make a special strap nail per the code which you reference in your post, which will save you some inspections issues down the road if you use them...

I also strongly recommend using a palm nailer for nailing all that strapping down.. its a BIG time and elbow saver for sure... they only cost about 75 bucks and work well with a small compressor... I bet I used at least 150 pounds of strapping nails in this house

[TheShrimper]

Very informative posts indeed, all worthy of retracting and remembering when needed. However, one thing that has failed to be mentioned, should also be figured into the equation. While a structure in question may be able to survive a 140 MPH hurricane, it may not be the case when the unpredictability of tornadoes, are contained in the ensuing feeder bands. You not only have your sustained winds, but the winds of the tornadoes as well. It isn't just the 140's knocking on your door, it's the tornadoes, microbursts ect, contained in the thunderstorm complexes, that most overlook. Seen it in Andrew, well north of the center.

[Frank P]

good post Shrimper... as I stated in my first post, if mother nature wants your house she is going to get it... your post only emphasizes the need to evacuate out of the path of the storm, and make sure your insurance is up to date... I was under insured for Katrina, not going to make that mistake again... build it high, build it strong, get it insured and then haul butt and get out of the way when it comes...

for all you not sure if you'll evacuate... if you're in a flood zone just listen to some of the 911 calls that came into the Biloxi Police dispatcher during the height of Katrina's surge... you might reconsider after listening to those horrific stories...

[weatherwindow]

I'll agree with hail2 on that one. Give me a home framed with Dade County Pine and I'll stay. I have seen to many that are still unphased over the years, from the old bungalows here on Pine Island to some of the older structures I have seen on/off of Krome Ave in South Dade. It says a little something, doesn't it?

second that...my shotgun house in kw(grinnell between virginia and united) has survived virtually unscathed since 1876..solid dade county pine from the studs to the roof joists...its really remarkable stuff..of course, not even dcp survives storm surge, but my place is 8 1/2 ft above msl and has never flooded(to my knowledge)...lets hope my luck holds.......rich

[baygirl_1]

good post Shrimper... as I stated in my first post, if mother nature wants your house she is going to get it... your post only emphasizes the need to evacuate out of the path of the storm, and make sure your insurance is up to date... I was under insured for Katrina, not going to make that mistake again... build it high, build it strong, get it insured and then haul butt and get out of the way when it comes...

for all you not sure if you'll evacuate... if you're in a flood zone just listen to some of the 911 calls that came into the Biloxi Police dispatcher during the height of Katrina's surge... you might reconsider after listening to those horrific stories...

Absolutely! We have some family friends who stayed in an evacuation zone in South Mobile County during Katrina. They said they'd never do that again. They were cut off from the evacuation route with the water rising. Fortunately, it didn't enter their home, but it scared the begeebies out of them!
Our home was built in 1996, also. We have a friend in construction who checked it out for us. He told us it was strapped together very well. However, somehow, a rogue gust or something knocked our chimney over during Katrina. Thank goodness we were not here-- and it happened after the heaviest rain had passed. We evacuate to get my mother to a safe place. Plus, after going through Frederic as a kid, I don't think I could take listening to that howling wind for hours and hours ever again. Though my DH talks about wanting to stay (by himself) to protect the house during a storm, he's always acquiesced to my pleas that I need him more than I need the house.

[MGC]

I remember the 3 story home we evacuated to during Betsy. It is located on Royal St. near Esplanade. At the height of the storm the home was swaying with every gust. My Mom started to get real worried when plaster started falling off the walls. It was an exciting night for sure.....MGC

[TampaSteve]

My in-laws' house in Punta Gorda survived the right-hand (bad) side eyewall of Charley with only minor damage...145 mph sustained with gusts over 160...fortunately, Charley was a compact, fast moving storm with minimal surge and the winds mainly pounded the back side of the house, away from the garage door (which is rated to 150 mph). The winds ripped light fixtures from the exterior walls and the screen cage over the lanai was completely blown away. The back side of the house faces Charlotte Harbor and was exposed to the full fury of Charley's eyewall. Fortunately, they had put up their storm panels, or all the sliding glass doors in the back would surely have blown in, resulting in the destruction of the interior of the house. If there had been a typical Cat 4 surge (15-20 feet), their house would have been completely inundated (along with the rest of Punta Gorda), because their living room floor is only 10 feet above sea level.

Their house is single-story, with reinforced concrete walls. The rebar runs from the foundation up through the walls and into the roof, making the house a very strong, unitized structure. It's basically built like a concrete bunker with windows. The roof tiles are flat instead of the barrel tiles like most people there have, and they didn't lose any of them (though several were cracked by flying debris). The only real damage other than the screen cage was one broken window pane in the side of the garage and they lost some soffit pieces and had a little rain and light debris (insulation from the house under construction next door) blown in to the attic. The interior of the house was completely intact and undamaged after the storm.

You want to build a house that will survive a major hurricane? One word: CONCRETE.

[TheShrimper]

Steve, what do you mean about the vertical steel running into the roof? Do you mean the tie beam? Before the tie beam is poured, it must be inspected to make sure that every three feet a rod extends down from the beam, thru the cell in the block and tied to the dowels placed when the footing was poured. An inspection hole in knocked out at slab grade to show inpectors that the steel is tied. The hole is then covered with plywood so the mud doesnt flow out. The tie beam is poured, but if the cells containing the verticle bars are plugged (intentionally, to save concrete) there is no connection between the beam and the slab except for the blocks laid. All the contractor needs to do when pulling the plywood off, is to slap some mud in the small hole to cover the fact that it was not poured, even though it looks like it has. I surmize that you were talking about steel tied off at the beam, and a conventional trussed roof with 90 lb hot mopped felt, with the tile placed on top. Don't see to many houses with pre cast roofs. I am sure there are a few, but not as many as in the Keys.

[Dionne]

I have never seen a residential with a "pre-cast" concrete roofing system. "pre-cast" panels are generally used in commercial applications.....where the panel is poured flat and then lifted and set. I don't think much of "pre-cast".....I would much rather see a "monolithic" pour......even if a cold joint is necessary....providing your steel spans across the cold joint.

I have been in areas where the entire residential was concrete.....even the pitched roof. The rebar extends out of the vertical wall and is bent and tied into rebar in the roof pour. It makes for an extremely strong structure. Only one problem.....if your near sea level and get the surge....all you have left is a concrete shell. When all your mechanical systems go under water.....your recovery expenses double......first you must demo out all the HVAC, wiring, plumbing.....then you rebuild in your existing structure.

There are numerous areas in the eastern caribbean that have concrete shells standing that have never been repaired. We looked at one on St Kitts. Ran the numbers and determined it simply was not a viable project. When you start estimating projects like these and your in the high six digit range before you ever sharpen your pencil....the answer is obvious.

[TheShrimper]

I have never seen one but sure would like to. Is the electrical coduit, gang boxes, ect all visible, or do they make allowences of sorts when they form up the walls. Plumbing as well, what about supply lines and drain pipes for kitchen and vanity sinks. Seems like it would be a nightmare if all was incased in poured concrete, if a repair needed done. Also, if the verticle bar should somehow shift to the inside of the form, moisture will eventually takes it's toll on it, and will rust and the wall will pop.