CONCRETE / CMU walls in hot / humid regions

[knosaj]

living on the gulf coast i have been told it is not a good idea to build with concrete / CMUs walls. Now, i am thinking id like a simpe solid concrete or CMU wall with little to no insulation or waterproofing....ideally.  they do it all over central and south america, through out all parts of asia, through out the islands, and many other places.

i understand the advatages of a thermal mass in desert like conditions where this and rammed earth is used. but i am interested in the gulf coast. i would rather not paint it, or insulate it. i mean what is the real issue. i know since it is so dense it offers little insulating properties. i am hoping that if the wall is thick enough, i will have no radiant transfer of heat through the wall. cave like. winters here are easy so i am not worried about cold as someone up north might be.

i know there are alot of these buildings around, schools, jails, gas stations, etc. i am just wondering why i dont see more residential projects built with the same materials.

anyone shed some light on this?

thanks in advance!

[knosaj]

nothing? i was hoping someone would at least be able to point me in the right direction. -thanks for any help.

[Don_P]

Block houses were popular here after the war for a time, very few are still occupied. These were uninsulated so heating them through the winter was a bear but mold was I think the biggest drawback. We cool off enough at night that the mass would cool to below the next days dew point and they were damp and musty. The ones that are still occupied have foam panels retrofitted to isolate the inside air from the block.

If you're in a code area I imagine you'll have to insulate it.

The concrete block people put out a number of passive designs in the 70's, they might exist on the web somewhere.

[archimedes]

I'm not sure I agree with your contention that CMU residential buildings are not popular in the Gulf Coast area.

I live in FL and they're all over the place.  Actually,  I would say from my personal experience that CMU houses are the preferred building method here.

[knosaj]

well, maybe not popular was not quite the right choice of words. I am not familiar with typical construction methods used in florida, but in houston, a residence using concrete or CMU walls is rare.  Now often you will see schools, gas stations and other low cost buildings usng them.

My largest concern is their insulating value. I understand that it will be low, but i am hoping that a wall on the south side, and thick enough to block radiant gain, could still be practical.

i am looking for the cheapest way to build an exterior load bearing wall and ive been told that concrete block is one of the cheapest ways to go. but, i dont want 15000$ utility bills either.

[MountainDon]

Looking at the CMU as a method to reach the goal of building a low cost load bearing wall may be correct. But it is not the whole picture. If this is to be a structure you will live in, not just store tools or whatever, the entire package must be considered. When everything is considered the usual stick built and insulated method is likely the most satisfactory. One of the things that may make it most satisfactory is probably that it is most cost effective for most residential purposes.

You never said what this building is; is it a residence? I assume it is.  Is it going to have a temperature and humidity controlled interior? Are you going to not have A/C and want to have thermal mass to assist in interior climate control? If that os the goal, that is probably one reason you don't see many residences built with CMU's. The few people I know close to the gulf coast live in insulated and A/C spaces.

That is to say, what is initially a cheap method of construction may end up costing more and in many ways, in the long run.

[BRUTAL]

check out autoclaved aerated concrete. its been uses for decades in europe. fire proof, non porous, light, and very thrmally efficient. Im going to build my house in a few years from this and theres an experianced builder in Houston I know that uses this product. It will standup to huricanes here in Houston as well a fire and flooding since it doesnt mold like wood or burn. Plus my insurance agent said my home owners insurance wont be as much as stick built saving even more.Also lower utilties and smaller hvac systems that stick built.
http://brantcustomhomes.com/