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Are construction companies supposed to fill concrete blocks in with cement, or do they leave 'em hollow?
I just want to make sure we're being specific about time frame. TODAY, like right now... if concrete blocks are used, they are required to be filled with a thick hydraulic cement (not like you would use in a shower floor). They'll even knock a hole in the bottom block where some air can escape, covered by a board. They'll even use a vibrator attached to a string to get the air bubbles out. The board is then removed, and the inspector needs to be able to see this area to verify that concrete made it from the top to the bottom as part of the inspection for certificate of occupancy. They've been doing this now for about 18-19 years.
There are some exceptions:
- Homes that are raised (on stilts if you will), the lower concrete walls are designed to "breakaway" in a flood. You'll see this commonly in places like the Keys / Key West, and the walls are made of CBS, but they are not filled. Furthermore, they are only tenuously attached to the posts at only two or three points at most... so if hit with a significant rush of flood waters (like 4 or 5 feet high), they are meant to break away so that it leaves the home on the posts. The first floor for homes like this are used for storage and vehicle parking, and that's generally it.
- Another situation in which they don't do this is if you have a garage that's external and not attached to the home. I have a three car garage that is an entirely separate structure from the home. When I go to my garage, I leave the house and walk about 50 feet to my garage. In this case, it does not have a certificate of occupancy, and therefore is not required to meet that level of safety standards.
Quote:
Originally Posted by MortonR
Typical construction of a single story home is like this:
Hope that clarifies it for you. This will at least give you an idea of how the house "pieces" are tied together as a unit to add strength and resilience. I am not a construction person but I've built a number of homes both myself and with contractors, so consider this a high-level description. Things have likely changed since my last home was built, so there's a good chance there will be corrections.
RM
I know this is a Tampa forum, so I'm speaking specifically about Miami-Dade standard (which encompasses Palm Beach, Broward, and Miami-Dade counties), but the use of concrete block construction is dependent entirely on what's being built. It's really weird. In South Florida, almost all large brand new homes are built with poured and molded walls, at least on the first floor. They'll actually build forms and fill the forms with solid concrete. They may still use CBS between a bay of windows, or something of that sort, but generally the big walls are now all poured concrete.
There are some other nuances as well. In renovation construction, you cannot connect a CBS wall to another CBS wall, and the connection must be made with poured concrete. Also, poured concrete with forms must also be used when building a wall that's used between major truss supports. Basically... poured concrete gets used now around 85% of the wall construction. Multi-family units and condos may also still use entirely CBS construction if they are only a single floor, despite the fact that their much larger counterparts use poured walls. I'm not a general contractor... I'm a computer programmer (or was, but now all I do is sit in meetings), but there's a weird if / then / else and decision tree for when to use CBS. But it gets more and more strict after every hurricane.
I still think there's some of this despite updated codes.
I've seen numerous two story houses built in the south County where the second story is stick built and not concrete block. Code or not, I can't imagine a means by which this type of construction would survive a storm like Ian when it hit south Florida.
RM
Why on Earth would they do that for 2-story houses? They should just make the whole thing concrete and finish the damn job right.
I just want to make sure we're being specific about time frame. TODAY, like right now... if concrete blocks are used, they are required to be filled with a thick hydraulic cement (not like you would use in a shower floor). They'll even knock a hole in the bottom block where some air can escape, covered by a board. They'll even use a vibrator attached to a string to get the air bubbles out. The board is then removed, and the inspector needs to be able to see this area to verify that concrete made it from the top to the bottom as part of the inspection for certificate of occupancy. They've been doing this now for about 18-19 years.
There are some exceptions:
- Homes that are raised (on stilts if you will), the lower concrete walls are designed to "breakaway" in a flood. You'll see this commonly in places like the Keys / Key West, and the walls are made of CBS, but they are not filled. Furthermore, they are only tenuously attached to the posts at only two or three points at most... so if hit with a significant rush of flood waters (like 4 or 5 feet high), they are meant to break away so that it leaves the home on the posts. The first floor for homes like this are used for storage and vehicle parking, and that's generally it.
- Another situation in which they don't do this is if you have a garage that's external and not attached to the home. I have a three car garage that is an entirely separate structure from the home. When I go to my garage, I leave the house and walk about 50 feet to my garage. In this case, it does not have a certificate of occupancy, and therefore is not required to meet that level of safety standards.
I know this is a Tampa forum, so I'm speaking specifically about Miami-Dade standard (which encompasses Palm Beach, Broward, and Miami-Dade counties), but the use of concrete block construction is dependent entirely on what's being built. It's really weird. In South Florida, almost all large brand new homes are built with poured and molded walls, at least on the first floor. They'll actually build forms and fill the forms with solid concrete. They may still use CBS between a bay of windows, or something of that sort, but generally the big walls are now all poured concrete.
There are some other nuances as well. In renovation construction, you cannot connect a CBS wall to another CBS wall, and the connection must be made with poured concrete. Also, poured concrete with forms must also be used when building a wall that's used between major truss supports. Basically... poured concrete gets used now around 85% of the wall construction. Multi-family units and condos may also still use entirely CBS construction if they are only a single floor, despite the fact that their much larger counterparts use poured walls. I'm not a general contractor... I'm a computer programmer (or was, but now all I do is sit in meetings), but there's a weird if / then / else and decision tree for when to use CBS. But it gets more and more strict after every hurricane.
What I do not understand is: why isn't this the building standard throughout hurricane alley, including the entire state of Fla??????
From someone that lives in a DoubleWide, our unit is glued and screwed. Taking off drywall was a challenge. IAN blew a lot of debris around, but no damage here. I saw residential homes not even in the path, with soffits/facia down and looking at them, they were nailed... rusty nails.. not enough fateners, too small of a fasteners.etc. Looked like shortcuts were made...to me IMO. I was asked to help with putting it back together. I was concerned of the construction quality that was done. I personally had new windows installed, storm doors added, and new entry doors. Some mobile home components are marginal. I also see old aluminum Jalousy crank windows in residential homes, that do nothing for homes around here. Whatever you live in... that has the potential for seeing Hurricanes or tornadows... look at the construction quality. After IAN, I will consider moving up north to sticks and bricks
Why on Earth would they do that for 2-story houses? They should just make the whole thing concrete and finish the damn job right.
The primary reason for the first floor of homes to be built out of concrete had nothing to do with hurricanes in the first place. It was done in the 1950s to prevent rot and mildew. In much of Florida, it generally rains every single day between noon and 2:00. The ground around your house is going to be constantly wet, and we also have subterranean termites. Early home builders came to realize that homes were getting mold, and the only way to stop this was to make the walls out of concrete.
Furthermore, single-story homes in Florida are also made using steel wall studs. They are actually not as strong as wood, even though they are made out of steel, and the only reason they are used is because they don't attract mold. These are the same studs that a commercial building uses to create partitions between two stores with drywall.
I'll answer the other part of your question below in response to Sinatras...
Quote:
Originally Posted by sinatras
What I do not understand is: why isn't this the building standard throughout hurricane alley, including the entire state of Fla??????
Cost.
Building a home out of concrete is exceptionally expensive. The wood comes from Georgia... so that's a simple path down I-95 or I-75, but much of the concrete mix needs to be imported by Cemex, etc. The cost to build a home entirely out of concrete is significantly more expensive than it is to simply build a home out of wood studs like everywhere else in the country.
And the second answer... "Vertical Federalism."
I'm sure we've all heard about the supremacy clause of the United States Constitution that grants authority of the Federal government to mandate laws across all states, so long as they don't violate any Constitutional amendments or the specific bill of rights. But in ABSENCE of a law, then there is no law for such a thing and the states can do whatever they want.
Likewise... the state of Florida, as do most other states, also practice vertical Federalism at the state level. Each state has their own constitution (as mandated by the U.S. constitution). Likewise... in absence of a state law, everything is legal in the state. Cities set their own building codes when not otherwise already mandated by the county, and each county sets minimum building codes when not otherwise already mandated by the state. Furthermore, each state sets their own minimum building codes when not otherwise already mandated by the Federal government.
The Federal government sets only the real basic building codes... it's up to the state, county, and city to determine what they want to do. Broward and Palm Beach both agreed to adopt Miami-Dade's standard... the others likely won't do it simply because they know it will dramatically increase the cost of home construction, which will lead to homes being less affordable, and further affecting the "working poor" as they call it.
Again... this is not a correct narrative. Much of the Florida coast abides by the Miami-Dade hurricane building standard. This includes, but is not limited to:
- Impact windows (that can withstand 125+ mph winds, effectively, bullet proof.
- Outward swing for all exterior doors (to resist implosion)
- Impact Doors (can withstand 125+ mph winds)
- Concrete construction, not just CBS construction, but literally poured concrete with rebar
- Galvanized-steel wall studs, not wood, but steel (not particularly stronger, but resist rotting)
- Roofing straps, the roof trusses are wrapped with a steel wrap that is tied directly to the concrete walls
Anyway, there's a whole list of things. When people see leveled homes, they automatically assume that these are all brand new buildings. Florida had massive growth in the 1950s when air conditioning was made possible (typically by window units), and the prevalence of dozens of military bases that were built throughout the entire state, from Key West, to the panhandle, to Jacksonville. There are dozens of military bases in Florida that no longer even exist. The location now occupied by Nova Southeastern University, one of the densest residential areas in Fort Lauderdale, and former location of the Dolphins Training Camp, was a major Naval Air Station.
Anyway, most of the homes in Florida were built in the 50s... many of them were wood, especially on the west coast. Some of those were built with CBS construction, which while stronger, are still not hurricane proof. Not every location in Florida supports the Miami-Dade standard. It's easy for us who all make 200k+ to scoff at people who own silly stick-built homes, but not everyone can afford that. So some counties build homes that are affordable... hence why they still allow trailer parks and manufactured homes. Those homes are held to a different standard, and the cost is drastically below the cost of a normal home.
Still, a Category 5 hurricane, which is essentially what it became at its peak, is not something really any building can withstand.
Anyway, most modern homes built today, depending on county, are built using the standards I mentioned above. Not all counties do this, because the prevalence of hurricanes are far less. Sorry if I seem miffed, but it does bother me when I see people make comments like this. Homes in Florida are built to a significantly higher standard. If a major hurricane like this was to pass through say... the state of Pennsylvania... there wouldn't be a single building still standing.
Absolutely right on. We are in Punta Gorda and got slammed by those nearing Cat 5 hurricane winds. From what I can see most of the houses, and other buildings looked to have very little damage, and many had none at all that we could see. We live outside PG, and our house had no structural damage. We lost many shingles, down to the plywood in a number of areas on the roof, and a number of soffits were torn out. Our well water treatment system was knocked over with broken pipes and components scattered all over. We got water intrusion through the ceiling once the roof had been breached. But the windstorm impact windows were great, as were the doors- they are metal and open to the outside as required by current code, IIRC. The garage door, with metal bar reinforcements both horizontally and vertically across the door, and locking latches on each side to prevent the door opening ( also current code,), held well, even though we heard loud scraping/ grinding noises from there during particularly strong gusts. We also have extra truss bracing in the roof system. We consider ourselves very lucky things were not worse. Our insurance adjuster, who came by two days ago, congratulated us on the strength of our house, said all we needed was a.metal roof ( properly installed) to make the house virtually impervious ( is that the word?) to hurricane damage. I expect much of the post- Charley construction in Charlotte County can also say the same thing.
We will need a new roof. We are considering a metal roof, but will have to see if we can afford it. The homeowners' insurance will not cover the cost of a metal roof, but we will see.
Absolutely right on. We are in Punta Gorda and got slammed by those nearing Cat 5 hurricane winds. From what I can see most of the houses, and other buildings looked to have very little damage, and many had none at all that we could see. We live outside PG, and our house had no structural damage. We lost many shingles, down to the plywood in a number of areas on the roof, and a number of soffits were torn out. Our well water treatment system was knocked over with broken pipes and components scattered all over. We got water intrusion through the ceiling once the roof had been breached. But the windstorm impact windows were great, as were the doors- they are metal and open to the outside as required by current code, IIRC. The garage door, with metal bar reinforcements both horizontally and vertically across the door, and locking latches on each side to prevent the door opening ( also current code,), held well, even though we heard loud scraping/ grinding noises from there during particularly strong gusts. We also have extra truss bracing in the roof system. We consider ourselves very lucky things were not worse. Our insurance adjuster, who came by two days ago, congratulated us on the strength of our house, said all we needed was a.metal roof ( properly installed) to make the house virtually impervious ( is that the word?) to hurricane damage. I expect much of the post- Charley construction in Charlotte County can also say the same thing.
We will need a new roof. We are considering a metal roof, but will have to see if we can afford it. The homeowners' insurance will not cover the cost of a metal roof, but we will see.
We have wood studs, not metal.
Glad to hear your damage was not horrible! Is your house new?
Absolutely right on. We are in Punta Gorda and got slammed by those nearing Cat 5 hurricane winds. From what I can see most of the houses, and other buildings looked to have very little damage, and many had none at all that we could see. We live outside PG, and our house had no structural damage. We lost many shingles, down to the plywood in a number of areas on the roof, and a number of soffits were torn out. Our well water treatment system was knocked over with broken pipes and components scattered all over. We got water intrusion through the ceiling once the roof had been breached. But the windstorm impact windows were great, as were the doors- they are metal and open to the outside as required by current code, IIRC. The garage door, with metal bar reinforcements both horizontally and vertically across the door, and locking latches on each side to prevent the door opening ( also current code,), held well, even though we heard loud scraping/ grinding noises from there during particularly strong gusts. We also have extra truss bracing in the roof system. We consider ourselves very lucky things were not worse. Our insurance adjuster, who came by two days ago, congratulated us on the strength of our house, said all we needed was a.metal roof ( properly installed) to make the house virtually impervious ( is that the word?) to hurricane damage. I expect much of the post- Charley construction in Charlotte County can also say the same thing.
We will need a new roof. We are considering a metal roof, but will have to see if we can afford it. The homeowners' insurance will not cover the cost of a metal roof, but we will see.
We have wood studs, not metal.
Good to hear.
Metal is definitely the way to go, unfortunately it's far more expensive than a traditional shingle roof, 3x-5x more, I've been told. But - it's supposedly good for 150 years!
RM
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Built out of toothpicks
