Hello: Do you think installing “hurricane clips ” is benefical here in central Arkansas. We do have tornadoes, but will hurricane clips even work in the that situation.
Thanks in advance
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I don't think anything would help in a tornado situation except one of those specially constructed safe rooms in the core of the house, or a basement. But, they would help with strong winds, or if a tornado is nearby but doesn't actually touch the house (don't know where the "boundaries" of a tornado are, but my feeling is that if your house was blown away by a tornado, hurricane clips would not have helped). In any case, I think they are a good idea--mainly as "insurance." I would think they may even help in an earthquake, not that they are a major concern in Arkansas.
We've had this go-round before.Hurricane clips are a waste of money and time if hurricanes aren't going to hit your house. Simpson has done a great job of lobbying the code writers to sell more hardware. Back in the mid 70's, I was on a crew that had to go into a tornado struck subdivision to do reconstruction work. Our first priority was to construct temp roofs on those homes that lost their roofs. Heres what I witnessed.Some of the roofs were ripped off and took the top plate with them. The simpson ties that are specced only fasten to the top plate. I can't scientifically say that they wouldn't help, but I'm skeptical.One house was gone completely, leaving only the foundation and chimney. The house next door had one broken window and a couple shingles missing. On the houses with the roofs gone, the drywall remained intact on the small rooms: baths, closets, etc. None of these houses had clips. My conclusion: if the tornado hits a couple houses away, clips aren't needed. If it hits on top of your house, clips won't help. If you install these to maximize your own safety, then find some that will extend down and fasten to the studs. Tie the studs to the foundation. Bob's next test date: 12/10/07
I definitely agree that Simpson-Strongie has built a strong business on convincing the building industry and officials that we "need" their products.
You are right though that that a wind resistant framed structure needs the roof tied to the studs tied to the foundation. The properly nailed sheathing does some of this but hardware can definitely help.
You said >> Some of the roofs were ripped off and took the top plate with them. The Simpson ties that are specced only fasten to the top plate. << Good observations. Here, being 100+ miles inland we don't get direct hits from hurricanes, but do get low power ones occasionally. Our wind zone is 100 MPH. We normally use H2.5s which as you say only tie to the top plate or maybe 1/2" and 2 nails into the lower top plate depending on how they are installed. As far as I know 99% of the houses here don't have the wall sheathing extending up and nailed to the uppermost top plate. Only the lower top plate. I wonder if it would help if instead of using H2.5s which barely include the lower top plate, we used something a little longer like the H2.5t shown on this page.
Along the same lines I really wish that 9' and 10' wall sheathing was commonly available. That, and 92 5/8" studs - here we only get 93s.
When we were building hurricane-proof housing in Puerto Rico they (LDR) used ties across every joint from foundation to rafters.
If your view never changes you're following the wrong leader
My conclusion: if the tornado hits a couple houses away, clips aren't needed. If it hits on top of your house, clips won't help
Yep. Tornados run to 200-300mph winds. The difference between a 'small' (F0) and a 'large' (F5) tornado is in the span of the damage on either side of the path. I ought to look it up, but and F0 is a 20m or swath, F5 1500m, IIRC.
Now, the inverse cube function applies with tornados, unlike hurricanes. Let's presume a 40m damage area--about a city lot "wide." Next lot over, the winds will be 1/8 the strength at the nieghbors. So house A has the rather difficult task on surviving 300mph winds, house B may only have to survive 60mph winds (and the splintered peices of House A raining down).
Hurricanes run to miles across. Inverse cube functions apply there, too--but in a storm sysytem that can be 100-300km across, there can be entire streets near maximum wind strength, and it's jsut quibbling over whether 90kt at this in is better than 80kt at the other end of the street.
The big twister that ran though Jarrett, just up 35 from you, was a monster. Spotters gave an on-ground width of 1500-1800m. But, you only needed to be a mile off track to have no damage at all.Occupational hazard of my occupation not being around (sorry Bubba)
one of the point that nobody talk about is, even if the house is destroyed it will hold some part of the house together to keep the debre from hitting your house and car. the damage from hurricane is not wind, but water and flying debrie like tree falling. if you was in a open field with no nearby water, no trees, no cars, no wheelbarrow. a typical built house be fine with little damage like shingle. But instead of building houses to minimum codes, we need to build to maximum codes.then a million people would not need to evacute a city during a storm.two ways to screw up concrete 1) concrete driver 2) concrete finisher
the damage from hurricane is not wind, but water and flying debrie like tree falling
Don't forget that add-insult-to-injury part where the t-storms in a hurricane breed up tornados just to keep it exciting.
Your point on maximum codes is apt, too. Rather like where jim & couple others wer going, that, unless you act ro tie the entire biulding together, anddown to the foundation, then adding just one thing or another is not much help.
There's something to be said for the argument of not "if" we should build better, but of "why wouldn't we want to."
My house (before I lived in it) survived a 60-70mph "line burst" windstorm. I don't know why--it's only tied to the pier blocks it sits on by gravity, that and the plubing fixtures. Occupational hazard of my occupation not being around (sorry Bubba)
"My house (before I lived in it) survived a 60-70mph "line burst" windstorm. I don't know why--it's only tied to the pier blocks it sits on by gravity, that and the plubing fixtures."They survive and stay put because they are heavy.I forgot to mention that in MI, we didn't start anchoring our frames to the foundation till the late 80's. I dont remember putting a sill plate on any house until about 1980 or so. The houses in the tornado neighborhood probably were just sitting on the foundations too. None were affected by that except the house that was totally gone. I'm sure the plates would have remained. Bob's next test date: 12/10/07
I would ask how many other homes in your area constructed the same way did not survive that storm. It seems to always be possible to have the exception but the wide spread damage seen in areas that have suffered direct hits points to doing more to keep the building together and tied down.
They can't get your Goat if you don't tell them where it is hidden.
how many other homes in your area constructed the same way did not survive that storm
Depends on how we define survive. Was a strecth of three houses with roofs stripped bare to rafters. Another batch on either side with damage through the roof sheathing. Typical damage, along the swath, was stripped off shingles.
So, the "level" of damage varied, and with the component of how well insured the house was (some would have been rental properties) being a factor, too.
It occurs, as I recollect after you posed the question that way, that the nost-damaged places had the fewest trees. Sobering thought that "too close" trees can protect as well as threaten.
We had a hail storm follow about the same "corridor" through town in '98, it was interesting to see the quality of the re-shingling jobs "laid bare" as it were. Enough damage out of that storm that when I bought my house in '99 it was one of the last to get roof repairs done. Seller's bank made it a condition of closing, and wound up with a complete reshingle, even though that was not needed.
Edit to add: In a three-block radius, my 55 y/o neighborhood only has 4 houses not built substantially like mine.
Occupational hazard of my occupation not being around (sorry Bubba)
Edited 1/20/2008 1:13 pm by CapnMac
damage of homes is mainly on "luck" i know of many that are within a 1000 feet of the gulf right where the eye of katrina came in, with zero damage, but if you lean against the house you can push it off its block. so why not invest $50 and add the clips for insurance. and we wonder why so many hacks are in the trade not doing code.If I had my way I make every house 100 miles from the gulf. 100% concrete. including roofs..two ways to screw up concrete 1) concrete driver 2) concrete finisher
I had my way I make every house 100 miles from the gulf. 100% concrete. including roofs.
Capitol idea.
But, it's good to remember that the fools and hacks outnumber "us"--they'd find a way to screw up "almost bullet proof" construction.
I've always wanted the time/money to experiment with concrete planks in coastal residential construction. But, I'm weird that way. I want to know what happened to the Plank/SIP hybrid that was all the rage a couple decades ago, too.
Oh, would you accept metal framing to 180-200mph in lieu of concrete? Something to be said for welded steel.Occupational hazard of my occupation not being around (sorry Bubba)
There is plenty of wind damage in hurricanes. It is a windstorm event. I've been in my house in 140 mph winds.
I was the only person on my block with an intact roof. I live 2 blocks from Pensacola Bay. But, I put on a roof( pink panther 25-year) to that code. It was less than 5 years old. Anything much older than that is a goner in high winds.
Simpson has done a great job of lobbying the code writers to sell more hardware.
I am so with you on this. In alot of cases hardware simply isnt needed.
I would like to ask a few question about your reconstruction work if you don't mind.
What did the homes have as wall sheathing? Back in those days (not like I was there, just seeing the results today) a whole grocery list of wall sheathing was used. Everything from Celotex, 3/8's plywood, brown fiberboard, 3/4" planks. Planks probably not so much.
Were they all sheathed the same? Which ones were the worse for wear if they had been hit?
My uncles and grandfather were hard into 1/2" plywood, I know not everyone was. Woods favorite carpenter
The neighborhood that was hit was relatively modern; probably 60's to late 60's vintage. The houses were celotex sheathing with let in 1x6 "windbraces". The roofs were plywood. I don't remember if it was 3/8" or 1/2". Each was common in those neighborhoods. It was trussed construction.We saw one house where the brick veneer wall on the garage fell off: no brick ties. The house was intact but the brick was laying on it's side. The path of the tornado was clear: you could see the swath going right through the area. Everything in the direct path was stripped. Trees that survived were bare with debris clinging. There were personal items strewn all over the neighborhoods: teddy bears, clothes, papers, etc. It's possible that some of the damage on the lessor damaged houses would have been minimized even more if the trusses were strapped. It didn't matter on some where the entire roof was gone with the doubled top plates. It is significant that most trusses were nailed with 16d cement coated sinkers though. The normal nailing standards was three spikes toe nailed. Most decent framers could create a substantial connection with three. Grain split is the greatest danger.I don't remember rebuilding any walls. Once the roofs were off, the tied in walls were able to withstand the winds. I think the neighborhoods were brick on the first floor and aluminum siding on the second floor. Bob's next test date: 12/10/07
Thanks I was curious about your experience.
I knew Celotex was popular around that time. Along with a few other options.
I think the intention of the hurricane straps isn't to protect a home from a direct hit, it's the near misses they are working on.
Woods favorite carpenter
jim.... we have to build for 110 mph
we use h2.5's
but we also plan our plywood sheathing to tie from mud sill ( bolts @ 4' oc ) to top plate
on 9' or 10' walls we have to lap minimum of 16" onto the studs... so our top plate is tied to the bottom plate , which is tied to the stud , which is tied to the shoe, which is tied to the band joist, which is tied to the mudsill
and the rafters are tied to the top plate with 2.5's or some other rated metal connector
then we start on the roof
yes... the OP should be using wind uplift contruction.... and yes , the insurance companies will keep lobbying for better construction to protect themselves and their policy holdersMike Smith Rhode Island : Design / Build / Repair / Restore
Our windload inFL is 140 mph. A lot depends on where your hous is. But after 160 mph, I wouldn't expect anything to stay.
I can guarantee Dorothy's house had clips holding the roof on. Otherwise she wouldn't have been able to go see the wizard.
None the less wouldn't clips go a long way toward helping your home survive a low power tornado or one that was not a direct hit?
I have been curious about your area since I saw a show about it.
Clemson University had built a house that displays all sorts of hardware to prevent wind damage. Not sure if it's still up or not.
Things like big angle iron bolted to the rafters and the top plates around the perimeter of rooms, covered up by crown molding. No ones the wiser.
We have to use 2.5's here as well, or an equal strap. Had to use H1's once or twice because the yard was out of 2.5's.
I was very hard on my guys to make sure that they nailed the living daylights out of sheathing, we used ringshank 8's at 6" OC for every piece of sheathing on a home . I made sure that the plates were hit very well.
For what nails cost, a few extra isn't going to break the bank for my GC's. Overkill maybe, but I can't wait to see others houses in the same subdivison fall apart due to details being too costly for them.
Woods favorite carpenter
In my line of work I have to pick my battles...
I will never tell someone he is using too many nails..., or generally that he is doing too good a job. Sometimes I have to remind myself of the last one since I have a close working relationship with most of my subs (the owner of that co) and I hate to see his guys wasting too much of his money. Most everything I pay for is by the job - not hour, etc. so it really doesn't make any difference to me except that I want my good subs to turn a reasonable profit so they will continue working for me. Case in point.... I had this concrete guy - did wonderful work and cheaply too... he went out business... I guess he was a concrete guy - not a business man.
I wouldn't build without them. Not much will help if with an F-5 tornado (261+ mph) but they'll give you a fighting chance with lesser ones.
http://www.tornadoproject.com/fscale/fscale.htm
Nothing will make a wood framed house withstand a direct hit from a tornado. But Most houses that are damaged don't get direct hits.
The winds insde a tornado may be 400 MPH. But if it just passes close by, you may "only" get 120 MPH winds. The hurricane clips may make a difference in a case like that.
But how many houses go through tornadoes? It's really a personal choice. In my case I used 'em.
If you're lucky that sort of thing won't stop there.
Clips will help like some of the previous posters said. But they have to be installed properly. They should tie the rafters to the studs as well as to the top plate. And the top plate should be held down by having the sheathing nailed into it all along its length.
Read this:
http://www.coastalcontractor.net/pdf/2007/0705/0705blow.pdf
Particularly page 6
Here, GC supplies lumber and hardware and sub suppies nails and staples. Some framing subs add $200 or whatever for nails, but it's a flat fee. Me - I try to get my carp subs to indluce as much as possible in their sq ft price, that way it makes it easier to build budgets I can stick to.
Can't see any harm.
And keep in mind that it's not just tornados you can have -- "downbursts" can cause a lot of damage, along with the ever-popular "straight-line winds".
>> Why do you guys make a sub supply nails? <<
Regional practice. They include it in their price so what's the difference? I see your point but do you think I'd hire subs who would be one-nailing studs?
Really though I think you must live in some kind of golden bubble building market if your GCs just phone up the building supply and say "give Matt Swanger whatever he wants". It's not a matter of trust, it just a matter of economics. If they are paying for it, then they won't waste as much. True- it could go the other way, but the sub always needs to be trusted in some fashion - although let it be known that I check after all my subs... it's kinda 2 sides of the same coin though - I trust my framer to use enough nails - your GCs trust you not to waste their money...
BTW - I also make them supply their own crane. Same reasoning - when I hire, crane is there for 3 hrs. When they hire, crane is there for 2.
Do you charge your trim mails to your builder's accounts too? If so, I'd have to say i never heard of such a thing...
We always supplied nails, joist hangers, and crane. A lot of the old timer builders also wanted the framers to supply soffit vents and gable vents. Some want the framer to supply ply clips! We refused to let the builders supply nails because we didn't want to hear them complain when they saw five laying on the floor. Additionally, they supply the wrong type. We know what we want. We use them every day and I get very picky. A nail is not just a nail. Bob's next test date: 12/10/07
You are doing new construction carpentry and getting paid by the hour?
BTW - sounds like you are not only a great carpenter but a great manager of the budget of the projects you sub on too... Or do I have this mixed up and you are the GC...?
Edited 1/19/2008 8:21 pm ET by Matt
I claim to be neither Matt.
I'll email you so the hijacking stops. Woods favorite carpenter