Concrete home construction

[Paddy]

I desided to start a new thread on Concrete home constrution. We touched on it in another thread concerning natural cooling. I travel a bit to Mexico, 100+ times and to Europe, 20+ times. It appears that masonary construction rules. I want to build with concrete/masonary products. I like the many advantages. To name a few, fire proof, decay proof, sound proof, bullet proof, tornado/storm proof, high thermal mass and very air tight. Down sides are diffacult to move walls/create holes and general US builders are not very experinced. With wood construction, engineering has become simple use of tables to know size of floor joist and rafters. Beams are sized by the seller/manufacture. Concrete construction requires carefull review of spans and beams/steel use. Many web sites list ICFs and their wonderfull traits. It can tough to sort it all out. One gripe I have is the R-equivalent claims based on U-Thermal mass. Thermal mass has advantages where daily temp swings are above and below inside temps. In some regions this occures nearly every day of the year, say NM, AZ. In many other locations these temp cycles only occure in the Fall and Spring. Also, ICFs have the Thermal mass isolated/insulated by foam. I have read, the Thermal mass needs to be located inside the structure. Windows gathering the winter time heat and blocking Summer heat are advatages of Thermas as well.

To get the full benifits of concrete construction, I will have all the floors, walls and roof of poured concrete. Any one here have a total or partial concrete home? Anyone else looking into building with concrete?

 

[Jagmandave]

I have been planning my ICF home for several years now, and I also think concrete is a great way to build a home, especially here in the midwest with out unique weather swings, where it can be 98* one moment then a tornado blows thru and it's 50* the next. Where we can need the heater on to go to work in the morning and the A/C to come home in the afternoon. That said, I was not planning to use the concrete as a thremal mass, but merely as "super" walls - strong, and termite as well as tornado proof. I think the insulative value of ICF's make it a good way to build an efficient home without going down the passive or active solar route. For example, most of the ICF homeowners I've spoken to say they can't really use a heatolator fireplace in the dead of winter without opening some windows a couple of minutes after starting the fireplace to cool off! In other words, the reason they use such construction in hot desert climes is for the insulative properties as much as thermal mass.......bottom line, ICF's make for easy construction, strong quiet homes, effiecint utility usage and so on - works for me.
That's not to say that's the only way to do it, rammed earth is gaining favor, as is good old adobe, but I think you need to suit the construction to the location..........

 

[_RaT_]

I desided to start a new thread on Concrete home constrution. We touched on it in another thread concerning natural cooling. I travel a bit to Mexico, 100+ times and to Europe, 20+ times. It appears that masonary construction rules. I want to build with concrete/masonary products. I like the many advantages. To name a few, fire proof, decay proof, sound proof, bullet proof, tornado/storm proof, high thermal mass and very air tight. Down sides are diffacult to move walls/create holes and general US builders are not very experinced. With wood construction, engineering has become simple use of tables to know size of floor joist and rafters. Beams are sized by the seller/manufacture. Concrete construction requires carefull review of spans and beams/steel use. Many web sites list ICFs and their wonderfull traits. It can tough to sort it all out. One gripe I have is the R-equivalent claims based on U-Thermal mass. Thermal mass has advantages where daily temp swings are above and below inside temps. In some regions this occures nearly every day of the year, say NM, AZ. In many other locations these temp cycles only occure in the Fall and Spring. Also, ICFs have the Thermal mass isolated/insulated by foam. I have read, the Thermal mass needs to be located inside the structure. Windows gathering the winter time heat and blocking Summer heat are advatages of Thermas as well.

To get the full benifits of concrete construction, I will have all the floors, walls and roof of poured concrete. Any one here have a total or partial concrete home? Anyone else looking into building with concrete?

I took a class on ICF construction. It is indeed a very interesting and great way to go. Check into Nudura. They offer a class on building and some ways to go other the the way you mention. There is so much to it in terms of advantages that I cannot list them here. One of the owners of Nudura, a fellow named Murray taught our class and was really informative. He was a carpenter for many years, moved on to ARXX ICF but found even that needed much improvement. I have found Nudura to be by far the best, simplest and best ICF installation product available. Mark

 

[dmccarty]

Paddy,

I'll play Devils Advocate.

With a concrete ceiling, I would expect that you are going to need a PE to do the load and design work which will cost extra. Then you will have to have a crew experienced in this kind of construction which I would guess would be a light commerical company. From what I have read they cost more than your every day house framer. How much extra do you pay for the ICFs? And how much does the concrete cost to fill the ICFs. Can you get that much concrete? When we built our house there was a severe shortage of concrete and what you could get was expensive. Ours was cheap at 90ish dollars a yard. I heard of some parts of the country playing $200 a yard. I don't think the shortage is as bad as it was but I heard it still going on in some places.

Will the house be in a sesmic zone? No way would I want to live in a house with a concrete walls or ceiling in CA. I'll take stick built with no bricks.

We were going to build with ICFs but I kept running into two problems, they cost 5% more than stick built and finding crews who had experience. 5% adds up to alot of money.

And we could accomplish many of your requirements with stick built construction. We have 2x6 walls with R19 insulation. There is one inch of foam on the outside providing another R5 or so. So we have a good R24 wall. We also have brick venneer and good quality metal clad wood casement windows. Its quiet in the house. We don't feel any air leakage or movement. Its very energy efficient and cheap to maintain HVAC/power wise.

For themal mass we have a fireplace hearth that has a double wall of bricks and the floor is a concrete slab. This definately helps temperature swings. While concrete walls my be bullet proof you windows will almost certainly NOT be bullet proof. What seems to cause most problems for houses is water. Our wall construction along with 28 inch roof overhangs keeps rain off the walls except with VERY windy storms. I would guess the average height from grade to the concrete slab is 24-30 inches which helps keep water from bouncing of the ground back on to the wood structure of the house. The water just hits brick and CMUs which ain't gonna rot.

What we did, and I would strongly encourage anyone who is building a home to do, is to site the house for passive solar. Unless there is a geographical/lot issue its a not cost item. With the proper placement of windows and overhangs you get free heating in the winter. And there is no cost or minimal cost to add to the house design. Active solar use is a different story and may or may not make money sense due to location and tax incentives.

Like I said we where going to use ICFs but for us we could get what we wanted cheaper and easier with stick construction. There are a few things I would like to have done differently with our house such as going up another 8 or 16 inches off of grade but we are 99.90% happy with the house. We certainly don't regret using stick built over ICFs.

Later,
Dan

 

[_RaT_]

In California, ICF built homes fly through engineering. In the Bay area, the building departments kick the ICF design through much easier then the wood frame homes (not to mention title 24, our energy design requirements). We design everything here with a lot of seismic qualities whether we live in earthquake areas or not. ICF homes cure very slowly because of the insulation which releases the moisture very slowly making the concrete very strong. With the engineering of the home comes all the rebar/lintel requirements. I would not have any issue with ICF homes in California. Remember too, its just a matter of time before we eventually get to the bottom of R values. Putting R 38 fiberglass insulation in your ceiling never yields R38 nor does R19 in your walls. Between the headers, wall pockets, wood studs and last but not least, air flow through the fiberglass, you never will get the rated value, not even close. On the otherhand, the same is not the same with EPS foam that ICF is made of. Theres a lot to learn about it and many pundits who lack the facts about ICF. I suggest you take the class and learn a whole bunch about ICF. Its an eye opener. I've been framing homes since 1973, its all I know but I love the idea of ICF.

 

[KubotaSteve]

There was a show on discovery (I think that was the channel) and it went through the process of a guy and his wife building an all concrete house. He ran into major cost overruns but a lot of it was where his house was at which was up a steep hill and in the side of a hill. They almost lost several full concrete trucks because they couldn't get the pumper truck up the hill into position and the concrete trucks started backing up.
Just seems like an awful lot of money that may not be recouped.

 

[bugstruck]

If I lived in tornado alley my home would be concrete. Wasn't aware there were packages or companies specializing in this though. Interesting. I've thought about doing one for some time now. With my commercial background it wouldn't be a big deal. We Americans aren't much on construction durability though compared to the rest of the World. So no surprise to see some dissenters to the idea. Is it superior? Not even close. More money? Factor in energy over 30 years and it's probably cheaper. That's the carry period on most home Mortages. I haven't studied it though. I just know it's got to be a much superior engineering design. This is an old framing carpenter speaking. I can build with wood to take an F1 tornado I believe, but nobody does. You don't want to know the cost of that either.

 

[Highbeam]

I have been reading up on concrete construction since I am a dorky civil engineer and I plan to build a house in the next couple of years. I am siting the home on a south sloping/facing hill to take advantage of passive solar which isn't a tree hugger thing it just makes sense. The home on a hill will be built into the hill so the floor slab will be at grade on the downhill side. The floor will be a 6" slab with radiant heating tubes poured into the slab. Being built into the hill means that the buried walls will be concrete. I like reinforced concrete naked on the interior for thermal mass. The retaining/stem walls will extend well above grade and perhaps to support the floor joists of the loft. Above that and on the south facing wall I see insufficient benefit to concrete walls and will switch to stick frame for the top part of the walls. On the roof I am researching the SIPS panels but even plain wood scissor trusses will work. I would not pour a concrete roof or ceiling.

There will be at least one interior wall of concrete to support the loft and to offer a very effective thermal mass. I think that the floor slab and concrete walls from burying the home will provide a huge benefit in terms of thermal mass and even temperatures. Ever noticed how comfortable the basement is?

Oh and no forced air heating/cooling.

There are a couple of sites that folks have created to document their construction of sustainable houses and since concrete construction is sustainable even by tree hugger standards, their documentation applies well.

Check out www.ourcoolhouse.com They link to several other project homes from which you can steal ideas as I have.

 

[RedRocker]

I saw a program on aeriated concrete construction, pretty interesting stuff, you could cut it with a saw and it floated if I remember correctly.

 

[Paddy]

dmaccarty,

You are correct about having an engineer review the design. On the other hand, I have seen foam form components designed by an Itailian Co that sell floor forms. They are pre-engineered for certain spans. On their web site they show all rebar placements with regards to the forms and tieing floors to walls. I don't have the web site handy, it's on another PC.

Cost; I feel the ICFs are pricey. A standard professionally poured 8"wall with foam attached is much cheeper. I have seen where foam with tabs for sticking to the concrete are placed in the standard form to get a simalar effect, foam-concrete-foam. I have been playing with the idea of 4" concrete-6" blue foam-4" concrete. The foam would have holes cut through to allow the concrete panels conected. Blocks, 4", of foam could be glued to the foam to keep it centered in the form and hold the rebar in place. Condoit could run in the foam as well. This will be more expensive than convential construction, but so was my 3500 sq-ft timber frame home.

Windows; European buildings have a...mini garage door that covers every door and window from the outside. They are made of metal and kind of work like a roll top desk. They have a unique feature where they can be closed but still let light in, partially. They way they do this; imagine 50 piano hings with major pin slop. When fully down, total sealed and darkin the room. As you begin to open it the pin slop exposes light through the cracks formed at the pins. This starts at the top and as you continue to pull the gaps progress down untill the last one raises up. Then as you pull more the entire pannel begins to raise. Very cool idea. Storm, fire, entry proof and darn near bullet proof. I would be interested in this type of covereing if I could get it in Al foam sandwitch like...garage doors. Talk about energy savings, windows are any homes big losers.

Siesmic: I have understood the dangers of masonary building was brick and block. It's all those joints. A soild poured box that was no taller than wide, would be pretty tough. But I do not live in an active siesmic zone.