Robert Premium Member join:2001-08-25 Miami, FL |
Robert
Premium Member
2012-Jun-3 9:55 am
Re: Tornados & House Structure Question..What i was trying to get at, is if the cinder block structure could withstand a tornado (even if the room is torn off and the house is gutted), wouldn't recovery be a little faster since the structure of the home is still there? |
|
mityfowl Premium Member join:2000-11-06 Dallas, TX |
mityfowl
Premium Member
2012-Jun-3 9:58 am
said by Robert:What i was trying to get at, is if the cinder block structure could withstand a tornado (even if the room is torn off and the house is gutted), wouldn't recovery be a little faster since the structure of the home is still there? Think of getting hit with 500 lbs dumb bombs |
|
|
to Robert
said by Robert:What i was trying to get at, is if the cinder block structure could withstand a tornado (even if the room is torn off and the house is gutted), wouldn't recovery be a little faster since the structure of the home is still there? Replacing the roof and the windows should be faster and cheaper than replacing the whole thing, that's for sure. However, I think even woodframe houses could be built to be much stronger with some simple enhancements. I do not know the building standards in Florida and other places in the south, but here pretty much everything is nailed together with a nailgun, and with enough force, it's not too difficult to pull those nails out. However, if screws were used instead, they would require a significantly bigger force. In addition glue could also be added for some additional strength and rigidity. Of course they would add quite a bit of labor cost, and make construction much slower. (Personally, I use screws as much as I can, but usually don't bother with glue since hurricanes and tornadoes are very rare around here) |
|
marigoldsGainfully employed, finally MVM join:2002-05-13 Saint Louis, MO |
to Robert
said by Robert:What i was trying to get at, is if the cinder block structure could withstand a tornado (even if the room is torn off and the house is gutted), wouldn't recovery be a little faster since the structure of the home is still there? Can the cinder block walls be reused once the roof is torn off and the house is gutted? If a full demolition is required before rebuild, then you have to deal with hauling off cinder blocks instead of wood. |
|
|
said by marigolds:Can the cinder block walls be reused once the roof is torn off and the house is gutted? If a full demolition is required before rebuild, then you have to deal with hauling off cinder blocks instead of wood. Why not? |
|
iknow Premium Member join:2012-03-25 |
to aurgathor
said by aurgathor:said by Robert:What i was trying to get at, is if the cinder block structure could withstand a tornado (even if the room is torn off and the house is gutted), wouldn't recovery be a little faster since the structure of the home is still there? Replacing the roof and the windows should be faster and cheaper than replacing the whole thing, that's for sure. However, I think even woodframe houses could be built to be much stronger with some simple enhancements. I do not know the building standards in Florida and other places in the south, but here pretty much everything is nailed together with a nailgun, and with enough force, it's not too difficult to pull those nails out. However, if screws were used instead, they would require a significantly bigger force. In addition glue could also be added for some additional strength and rigidity. Of course they would add quite a bit of labor cost, and make construction much slower. (Personally, I use screws as much as I can, but usually don't bother with glue since hurricanes and tornadoes are very rare around here) screws can't be used instead of nails because they aren't rated for shear strength, they are hardened, and can snap, where a nail will bend. they CAN be used in addition to the required amount of nails, though. |
|
marigoldsGainfully employed, finally MVM join:2002-05-13 Saint Louis, MO |
to printscreen
said by printscreen:said by marigolds:Can the cinder block walls be reused once the roof is torn off and the house is gutted? If a full demolition is required before rebuild, then you have to deal with hauling off cinder blocks instead of wood. Why not? Well, at a certain level of placard, mandatory demotion comes into play. But after doing some research, missing roof and interior walls gutted is only a mandatory yellow placard at the highest level. As long as no more than 2 rooms are destroyed, it could still avoid red placard and potential mandatory demolition (red by itself is not a mandatory demolition, but some cities will automatically issue a demolition order on a red placard house). |
|
|
disconnected to iknow
Anon
2012-Jun-4 3:02 pm
to iknow
Based on my own testing, it takes about 25X the force to pull screws out, versus nails of the same size. I put larger screws about an inch apart on the roofing, ext walls, etc. Use lag bolts to hold structural members together, with the addition of screws in between for extra bonding. I can assure anyone that the wood will shred apart before the screws give way. I see new construction using large staples now and flakeboard (OSB) for sheathing. Houses in the 60s used to use Cleotite on 2x4 studs. My first house was nearly destroyed in an F1 tornado in the early 60s because of this shoddy contractor construction. When I built my own house, I decided to build to withstand a 30KT blast at 1 mile, or 300MPH gusts. Contractor built homes are dangerous. I don't feel secure in them. I can kick a hole in the wall easily. How would that keep a burglar out, much less a tornado? |
|
|
to iknow
said by iknow:screws can't be used instead of nails because they aren't rated for shear strength, they are hardened, and can snap, where a nail will bend. they CAN be used in addition to the required amount of nails, though. References? The screws I normally use for framing (#9 x 3.5") has a somewhat higher diameter than the comparable nails, and if they're subjected to a force sufficient to snap them, then I think all bets are off and an equivalent nailed structure would fail earlier than that. |
|
|
|
to marigolds
said by marigolds:Well, at a certain level of placard, mandatory demotion comes into play. But after doing some research, missing roof and interior walls gutted is only a mandatory yellow placard at the highest level. As long as no more than 2 rooms are destroyed, it could still avoid red placard and potential mandatory demolition (red by itself is not a mandatory demolition, but some cities will automatically issue a demolition order on a red placard house). I am not familiar with the placard thing you mention but I was based on that if the block structure was not damaged and its structural integrity was kept why not reuse the same structure with a new roof and interior walls? A house could be damaged with a missing or badly destroyed roof but still have the exterior walls intact. |
|
marigoldsGainfully employed, finally MVM join:2002-05-13 Saint Louis, MO |
said by printscreen:said by marigolds:Well, at a certain level of placard, mandatory demotion comes into play. But after doing some research, missing roof and interior walls gutted is only a mandatory yellow placard at the highest level. As long as no more than 2 rooms are destroyed, it could still avoid red placard and potential mandatory demolition (red by itself is not a mandatory demolition, but some cities will automatically issue a demolition order on a red placard house). I am not familiar with the placard thing you mention but I was based on that if the block structure was not damaged and its structural integrity was kept why not reuse the same structure with a new roof and interior walls? A house could be damaged with a missing or badly destroyed roof but still have the exterior walls intact. In a disaster, a damaged house receives a placard ranging from green to red. Green are safe to occupy. Yellow can be entered but have restrictions on occupancy. Red cannot be entered except for emergency operations. The rule of thumb is green can be repaired in 30 days, yellow can be repaired but in more than 30 days, red is not economically feasible to repair. |
|
|
After Isabel in 2003 and Irene in 2011 I saw plenty of damaged homes and I saw no Green, yellow and Reg tags. Must be something in your area to keep your government workers busy.
I do see on tv sometimes after a fire they condemn the structure until it can be repaired. |
|
marigoldsGainfully employed, finally MVM join:2002-05-13 Saint Louis, MO |
said by Jack_in_VA:After Isabel in 2003 and Irene in 2011 I saw plenty of damaged homes and I saw no Green, yellow and Reg tags. Must be something in your area to keep your government workers busy.
I do see on tv sometimes after a fire they condemn the structure until it can be repaired. It's a FEMA mandate adopted post-Katrina. |
|
|
said by marigolds:said by Jack_in_VA:After Isabel in 2003 and Irene in 2011 I saw plenty of damaged homes and I saw no Green, yellow and Reg tags. Must be something in your area to keep your government workers busy.
I do see on tv sometimes after a fire they condemn the structure until it can be repaired. It's a FEMA mandate adopted post-Katrina. I didn't see any here after Irene which was post Katrina |
|
robbin Mod join:2000-09-21 Leander, TX |
robbin
Mod
2012-Jun-4 11:45 pm
Sounds like you should complain to FEMA. |
|
|
to marigolds
I travel regularly to Massachusetts and have seen this sign in abandoned buildings. But I have been told it is to tell firefighters not to enter the building during a fire.
|
|
|
to Jack_in_VA
After the building next to ours had a fire in which ten 100 pound propane tanks exploded, they "condemned" our building. We were allowed to enter and do stuff in the building, but we just couldn't live there (I guess that meant everything except sleeping was OK). They also turned off the electric and gas.
After the inspectors checked the electric and gas, the red sticker was removed, and we were allowed to live in the building again. |
|
|
to robbin
said by robbin:Sounds like you should complain to FEMA. For what? We already have enough snitches and busybodies. I don't need to add to it. Besides it's not my problem or any of my business. |
|
marigoldsGainfully employed, finally MVM join:2002-05-13 Saint Louis, MO |
to Jack_in_VA
said by Jack_in_VA:said by marigolds:said by Jack_in_VA:After Isabel in 2003 and Irene in 2011 I saw plenty of damaged homes and I saw no Green, yellow and Reg tags. Must be something in your area to keep your government workers busy.
I do see on tv sometimes after a fire they condemn the structure until it can be repaired. It's a FEMA mandate adopted post-Katrina. I didn't see any here after Irene which was post Katrina Ah, Virginia was never approved for individual assistance, so they never did placards. » www.fema.gov/news/event. ··· id=15594The damage assessment lists no placarded buildings because there was no individual assistance. » www.fema.gov/pdf/news/pd ··· 4024.pdf(p2 Minor Damage is green placard, Major Damage is yellow, Destroyed is red) In contrast, New Jersey was approved for individual assistance, so they had 2,080 declared major damaged: » www.fema.gov/pdf/news/pd ··· 4021.pdfThough they might have been allowed to skip individual assessment and declare everything Yellow, since it is odd to have all yellow at that magnitude. For our tornado here last year, we had a wide range of structure damage: » www.fema.gov/pdf/news/pd ··· 1980.pdfThe AIA handbook explains the placards in detail » www.aia.org/aiaucmp/grou ··· 7904.pdf |
|
iknow Premium Member join:2012-03-25 |
to aurgathor
said by aurgathor:said by iknow:screws can't be used instead of nails because they aren't rated for shear strength, they are hardened, and can snap, where a nail will bend. they CAN be used in addition to the required amount of nails, though. References? The screws I normally use for framing (#9 x 3.5") has a somewhat higher diameter than the comparable nails, and if they're subjected to a force sufficient to snap them, then I think all bets are off and an equivalent nailed structure would fail earlier than that. references are all over, look on google for "screws for framing" and you can ask your town board too, there are instances where people used screws in stead of nails, and the town inspectors made them use nails instead. here's some info, metal fatigue and building codes come into play. » www.contractortalk.com/f ··· s-90287/ |
|
MaynardKrebsWe did it. We heaved Steve. Yipee. Premium Member join:2009-06-17 |
to aurgathor
said by aurgathor:said by iknow:screws can't be used instead of nails because they aren't rated for shear strength, they are hardened, and can snap, where a nail will bend. they CAN be used in addition to the required amount of nails, though. References? The screws I normally use for framing (#9 x 3.5") has a somewhat higher diameter than the comparable nails, and if they're subjected to a force sufficient to snap them, then I think all bets are off and an equivalent nailed structure would fail earlier than that. Take a look at the Simpson Strong-Tie catalog » www.strongtie.com/ and see what they say about shear strength of screws vs. nails. |
|
|
to iknow
a) search terms with over 30 million hits are not references b) a message board is not a reference either |
|
aurgathor |
to MaynardKrebs
said by MaynardKrebs :]Take a look at the Simpson Strong-Tie catalog »www.strongtie.com/ and see what they say about shear strength of screws vs. nails. There is a 200+ pages catalog there -- please point out the exact section or page, or quote it here. |
|
MaynardKrebsWe did it. We heaved Steve. Yipee. Premium Member join:2009-06-17 |
said by aurgathor:said by MaynardKrebs :]Take a look at the Simpson Strong-Tie catalog »www.strongtie.com/ and see what they say about shear strength of screws vs. nails. There is a 200+ pages catalog there -- please point out the exact section or page, or quote it here. You have Mk1 eyeballs, don't you? |
|