Insulating Florida concrete block homes

[Masquernom]

We've been considering moving to a 55+ community and have looked online at some in Florida. They say the houses are concrete block. I'm curious if anyone knows how they insulate the walls in this type of construction? I don't think concrete block provide much insulation alone.

 

[boog]

Here are some videos which show construction details at a large 55+ community in Ocala, FL. I live in a different community nearby and our home was similarly constructed. We’ve been very satisfied with the energy efficiency compared to our previous brick veneer home in southern Georgia.
https://ontopoftheworldcommunities.com/construction-methods-at-on-top-of-the-world/

 

[ShokWaveRider]

Ours has Tyvek inside and out. Studs go on top of the inside insulation and stucco on the outside.

 

[ScoopKona]

Two things to consider about insulation:

1) Insulation only slows the transfer of heat. It cannot stop it. And if the concrete heats up in the sun, the insulation then does a dandy job holding the heat IN. (It slows heat transfer in both directions.)

2) The most important consideration is the thermal coefficent of the building material and the thermal mass of the structure. (This is why stone ovens stay hot for hours after the fire goes out.)

The old Plantation style home is the way to go in Florida (and any humid subtropical locale) -- wood frame houses, single walled, with an eye toward maximum air flow. With cupolas on the roof to act as heat chimneys.

If you want comfort, that's the way to go.

Insulating a concrete house will make it hold heat more effectively. You can't win the battle vs. the sun. Not without massive power bills and an enormous air conditioning system.

 

[ERD50]

Two things to consider about insulation:

1) Insulation only slows the transfer of heat. It cannot stop it. And if the concrete heats up in the sun, the insulation then does a dandy job holding the heat IN. (It slows heat transfer in both directions.) ...

I'm pretty sure the insulation is on the inside of the concrete walls.

... The old Plantation style home is the way to go in Florida (and any humid subtropical locale) -- wood frame houses, single walled, with an eye toward maximum air flow. With cupolas on the roof to act as heat chimneys.

If you want comfort, that's the way to go.

Insulating a concrete house will make it hold heat more effectively. You can't win the battle vs. the sun. Not without massive power bills and an enormous air conditioning system.

That style home made sense before air conditioning. Most people are going to want a lower humidity than the outside air in FL. And they are going to want cooler than ambient temps. So the house needs to be sealed and air conditioned.

The air flow ideas might make sense for the outside of the house. Overhangs to keep some of the sun off, and outside air flow over the outside of the walls to pull away any heat build up from the sun.

-ERD50

 

[Aerides]

Ours has Tyvek inside and out. Studs go on top of the inside insulation and stucco on the outside.

Pretty standard in S. Fla too.

wood frame houses, single walled, with an eye toward maximum air flow.

Wood frame houses no longer exist in most areas in Florida, and would not be legal to build, or insurable, not since at least 1992 codes. Some municipalities still allow wood on the 2nd floor, but many don't.

Most focus here on good roof insulation. Not hard to keep the electric bill well under $200 in season with a standard AC system just like other parts of the country use.

 

[Tom52]

We live in Florida and have a concrete block and stucco (CBS) house with decent double pane windows. Nice and quiet compared to wood frame houses we have lived in before. In the Florida summer, max air flow does not apply as you don't want hot/humid air circulating thru the house. You want good insulation and A/C. We have 2005 sq. ft in the house and 630 sq. ft. in the garage which is also air conditioned. House and garage is very reasonable to cool, and I am sure part of the reason is because of the CBS construction. Our house is total electric including clothes dryer, water heater, and range.

Our total monthly electric bills 2021 cooling season:

April. $98.06
May. $103.10
June $104.34
July $164.68
August $163.36
Sept. $148.69
Oct. $163.48
Nov. $96.69

 

[ScoopKona]

That style home made sense before air conditioning.

I'm originally from the Florida Keys. That style of house still makes sense today. The most comfortable house I lived in was cavalry officer's quarters from the 1800s -- moved from Ft. Zack to its current location near the Key West Bight.

It includes the roof cupolas and single wall construction, with long overhangs. It was also placed with two buildings, L shaped, with a gap between them for air flow.

This house was fairly comfortable, even in the summer, with just a ceiling fan. And on the worst days, a room air conditioner to knock the heat down at bed time was sufficient.

Having spent plenty of time in the modern concrete bunkers which pass for housing in Florida, I much prefer the old style.

If I was going to live in the desert full time (that'll be the day), I'd build a Moroccan riad. Same reason -- match the architecture to the climate.

The houses I'm building here in Hawaii are bamboo and basically look like the old Swiss Family Robinson movie, minus the treehouse aspect. (Although I might just build a tree house -- because it'd be cool to have a tree-top observation loft.)

 

[Out of Steam]

Two things to consider about insulation:

1) Insulation only slows the transfer of heat. It cannot stop it. And if the concrete heats up in the sun, the insulation then does a dandy job holding the heat IN. (It slows heat transfer in both directions.)

<SNIP>

The old Plantation style home is the way to go in Florida (and any humid subtropical locale) -- wood frame houses, single walled, with an eye toward maximum air flow. With cupolas on the roof to act as heat chimneys.

There are a couple of competing requirements for a house in an extremely hot, humid place like Florida.

First is surviving an extended power outage after a hurricane or tropical storm. Since the plantation house is what was built before the existence of air conditioning, and high ceilings keep the hottest air overhead, it should do that well. I'd go for the higher ceilings and roof overhangs of such a house.

Second is efficiently reducing humidity and temperatures using air conditioning. With dew points not falling below the mid-60s in the summer, opening up the house just admits humidity that the residents have to pay to remove later. So, relying on the house being opened at night is problematic.

The requirements compete, though storm survival has to take precedence.

If the masonry walls are white, and shaded with generous overhangs, they should stay close to the daily average temperature, which is less than 20 degrees higher than the inside. The humidity of Florida makes temperatures above 100 degrees unlikely.

 

[ERD50]

I'm originally from the Florida Keys. That style of house still makes sense today. The most comfortable house I lived in was cavalry officer's quarters from the 1800s -- moved from Ft. Zack to its current location near the Key West Bight. ...

Well, that's fine for you. But I am very skeptical that most people in FL would consider that humidity and temperature to be "comfortable", even with some air flow. Sure, a house designed to optimize that air flow and sun block will be much more comfortable than one that isn't. But that just isn't going to cut it for most people. They are going to want some humidity relief 24/7 (and temperature, but I'd guess humidity relief rates higher if you had to choose).

-ERD50

 

[Out of Steam]

Pretty standard in S. Fla too.
Most focus here on good roof insulation. Not hard to keep the electric bill well under $200 in season with a standard AC system just like other parts of the country use.

The summer design temperatures in Orlando, Florida are no higher than in Atlanta or Central Virginia. The difference is more hours of system operation for humidity removal and hot weather lasting for more of the year. The system doesn't need to be bigger, it will just wear out faster.

I'm interested in adding attic insulation to our house in Virginia, mainly to keep temperatures more even in a long power outage.

 

[Bamaman]

It's a heck of a lot hotter in Louisiana, Arkansas and Mississippi in the Summer. The ocean and Gulf actually keep Florida a little cooler in Summer than the states inland.

Florida has those concrete block homes to combat hurricanes. I would much better prefer a conventional framed and insulated home--but they have to be built like a tank to meet Florida's building codes.

It's just a shame that insurance costs are out the roof on Homeowners in Florida. And insurance companies collect those sky high premiums for 8-10 years between hurricanes. There's a pile of money invested somewhere waiting to pay for natural disasters when they do come.

 

[Out of Steam]

Well, that's fine for you. But I am very skeptical that most people in FL would consider that humidity and temperature to be "comfortable", even with some air flow.

It's worth mentioning that the current population of Florida is 25 times higher than in 1920. So few people considered the state permanently (year-round) inhabitable at all before air conditioning.

 

[GTFan]

I'm originally from the Florida Keys. That style of house still makes sense today. The most comfortable house I lived in was cavalry officer's quarters from the 1800s -- moved from Ft. Zack to its current location near the Key West Bight.

In the Keys? Maybe, with the regular breezes you get.

In central FL? No frickin' way.

 

[JP.mpls]

Masquerer,
A little off topic.
A new home is going up on the next block over from my townhome.
It is on an open lot on a canal.
They hauled in 4-5' of sand, and then routed rebar through channels they dug into the leveled sand. I think they also pounded rebar down into the sand.
They are going to poor the concrete footings soon.
It seems weird to me, like the whole house is just sitting in the sand that was recently hauled in. It must work.
JP

 

[ScoopKona]

It seems weird to me, like the whole house is just sitting in the sand that was recently hauled in. It must work.
JP

Never make the assumption that things have been thought through in Florida. There are condos in Miami that have weak concrete you can push your hand through -- because they made the concrete with beach sand, sea water, and non-galvanized rebar. It saved a few dollars compared to doing it right.

The old Conch houses in the Keys and the old plantation houses elsewhere were built by ship's carpenters, mostly. That's why they're still standing -- more than 100 years old -- while the more recent buildings crumble around them.