Building a Concrete House

[pb4uski]

I think the play is that these houses can be built for very little so housing would be more affordable... about $4k for a basic house IIRC.

 

[Willers]

Built a boathouse into the hill at our lake house using this construction. Worked great and I'd definitely use it again. We framed inside walls just for the ease of running electrical and water, but that wouldn't be required.

 

[calmloki]

Built a boathouse into the hill at our lake house using this construction. Worked great and I'd definitely use it again. We framed inside walls just for the ease of running electrical and water, but that wouldn't be required.

Which construction? Printed/extruded or poured concrete wall or wire frame with sprayed on concrete? Dome roof? The dome home we offered on in Prescott had wiring in plastic conduit in the sprayed walls but a big drawback was the curved dome walls: picture hanging? Unless one is a fan of exposed conduit/plumbing runs one really needs to have a solid notion of exactly where plumbing and outlets and lights will be forever with concrete walls - unless, as you did, you do false walls.

 

[cathy63]

My brother-in-law is building a garage/workshop with a small dwelling unit above using the foam blocks that have rebar and concrete inside. He's done the garage floor and walls so far, but he's kind of vague about the plumbing and electrical for the upstairs unit, so I'm quite interested to find out how all that works out in the end.

This photo was before they poured the walls.

 

[Willers]

Which construction? Printed/extruded or poured concrete wall or wire frame with sprayed on concrete? Dome roof? The dome home we offered on in Prescott had wiring in plastic conduit in the sprayed walls but a big drawback was the curved dome walls: picture hanging? Unless one is a fan of exposed conduit/plumbing runs one really needs to have a solid notion of exactly where plumbing and outlets and lights will be forever with concrete walls - unless, as you did, you do false walls.

It was ICF. It went up quickly and we just used waterproofing on the hill side wall before backfilling.

 

[Willers]

It was ICF. It went up quickly and we just used waterproofing on the hill side wall before backfilling.

As a further note we used Hardi on the upper/exposed sides.

 

[pb4uski]

My brother-in-law is building a garage/workshop with a small dwelling unit above using the foam blocks that have rebar and concrete inside. He's done the garage floor and walls so far, but he's kind of vague about the plumbing and electrical for the upstairs unit, so I'm quite interested to find out how all that works out in the end.

This photo was before they poured the walls.

I had looked into these. Plumbing would probably come up through the floor... for electrical they have specialty heated knives that cut the styrofoam for receptical and light swtch boxes and wiring.. then you install the boxes and rough in the wiring and start putting up drywall.

 

[Sunset]

My brother-in-law is building a garage/workshop with a small dwelling unit above using the foam blocks that have rebar and concrete inside. He's done the garage floor and walls so far, but he's kind of vague about the plumbing and electrical for the upstairs unit, so I'm quite interested to find out how all that works out in the end.

This photo was before they poured the walls.

Will he be doing the second floor in the same way, or building a stick (2x4 or 2x6 stud) top floor ?

 

[cathy63]

I had looked into these. Plumbing would probably come up through the floor... for electrical they have specialty heated knives that cut the styrofoam for receptical and light swtch boxes and wiring.. then you install the boxes and rough in the wiring and start putting up drywall.

That makes sense for the electrical. The plumbing is a mystery though. The pad they poured for the garage floor doesn't have any water supply or drains, so I guess those will be external and maybe surrounded by some kind of wooden box with insulation. Let's just say nobody in the family is too surprised about the vagueness of the plans and we are all just waiting to see what he ends up with.

 

[cathy63]

Will he be doing the second floor in the same way, or building a stick (2x4 or 2x6 stud) top floor ?

See previous comments about vagueness of plans. I asked that exact question on a family zoom call, but the answer sounded like the concrete walls were already 1.5 stories and there would be an A-frame roof above. Then I saw the photos and that didn't make sense, so now I have no idea.

 

[meierlde]

Thanks everyone for the feedback and information. Where we are currently at (South Korea) almost all of the houses here are built out of concrete. Was hoping there was more experience on concrete builds in the states, as our online research echoes what everyone is saying on this thread; expensive and hard to find contractors to do it. Particularly in the more rural areas we would be looking to retire to.

It's such a shame because in theory it should be less expensive as you are dealing with fewer materials to get a sturdier and longer lasting house. We love our concrete homes out here and maybe one day it will be more widely adopted back in the states...maybe not.

It very much depends on where in the US you are looking concrete or cinder block houses are common in south florida due to the huge termite problems there, plus they survive hurricanes better. Down there the insulating nature of ICFs is not as needed as further north. Here is an article from the Orlando Sentinel on the comparison between frame and block houses. You can reinforce the blocks with rebar. Note that because lumber is expensive in the Carribbean a lot of housing there is also block. To increase insulation foam panels could be put on the inside and outside.

 

[troutnut1]

I appraised a nice one a while back for a local news sports guy who was a big hunter. He wanted a log home but without the maintenance. He had a concrete home that was built like a tilt-up (think Costco) but the outside had every appearance of being real logs. I asked him how he liked it and he said he did, but that he really missed having logs inside to hand all his trophy mounts. Inside was drywall like most homes and that’s not how he had envisioned it.

 

[ACEIV]

Been looking for about 15 years at ICF

There are some good points raised, and a few that I would add...


1. ICF has been proven...cost is about 20% higher than stick, depending on your area's cost of concrete.
2. Finding an installer with experience is essential, and not going to send his kids to Ivy league schools on your project.
3. Wifi isn't an issue, just run Mesh pods via wire in the attic (plan for it)
4. Plumbing is easy, comes out the floor, and can also be installed in wall using hot knife like the electrical.
4. You can build out the walls an inch with strapping to allow for the Styrofoam to be untouched in areas.
5. ICF is VERY energy efficient...in addition to lower tonnage of equipment needed on HVAC, lower costs are observed every month.
6. Other cost offsets are higher selling price, as people who learn about it love it, and combined with the right roof, can lower your annual insurance bill.
7. Sound abatement is fantastic, good for those of us who are light sleepers or suffer from PTSD or similar.



In summary, if people cared about structure more, and the latest appliances,patterned tile, or the latest fashion trend that will be out of date in 10 years, most people would go for ICF, SIPS, or Block walls. But as any builder will tell you, very few home buyers will get overly excited about withstanding hurricane force winds (unless there is a hurricane on its way.


Hope that helps.

Alex

 

[MarkiePippo]

Cinderblock houses are pretty common in Florida. They can not use the styroforms because of Termites. We can not use them in Georgia for the same reason. I have written to this Old House a few times to mention that in their show but I guess it got lost in the mail. Here in Georgia they use the styroforms to pour the basement then they remove all of the outside pieces before they backfill. Looks like a waste but Termites can be bad around here.

 

[ACEIV]

Cinderblock houses are pretty common in Florida. They can not use the styroforms because of Termites. We can not use them in Georgia for the same reason. I have written to this Old House a few times to mention that in their show but I guess it got lost in the mail. Here in Georgia they use the styroforms to pour the basement then they remove all of the outside pieces before they backfill. Looks like a waste but Termites can be bad around here.

Hi Markie,



Good point. However there are several options in Termite prone areas. Several manufactures are injecting insecticide in the foam. In addition, there are a couple of barriers or membranes that work. EPS foam is not a food source for termites also.


Alex

 

[powersmo]

Also, do a search on like Youtube for building with cinder blocks. After Germany was so bombed out from WW2, they used cinder block construction to reduce the future possibility of destruction from fire.

 

[bolt]

There are some good points raised, and a few that I would add...


1. ICF has been proven...cost is about 20% higher than stick, depending on your area's cost of concrete.
2. Finding an installer with experience is essential, and not going to send his kids to Ivy league schools on your project.
3. Wifi isn't an issue, just run Mesh pods via wire in the attic (plan for it)
4. Plumbing is easy, comes out the floor, and can also be installed in wall using hot knife like the electrical.
4. You can build out the walls an inch with strapping to allow for the Styrofoam to be untouched in areas.
5. ICF is VERY energy efficient...in addition to lower tonnage of equipment needed on HVAC, lower costs are observed every month.
6. Other cost offsets are higher selling price, as people who learn about it love it, and combined with the right roof, can lower your annual insurance bill.
7. Sound abatement is fantastic, good for those of us who are light sleepers or suffer from PTSD or similar.



In summary, if people cared about structure more, and the latest appliances,patterned tile, or the latest fashion trend that will be out of date in 10 years, most people would go for ICF, SIPS, or Block walls. But as any builder will tell you, very few home buyers will get overly excited about withstanding hurricane force winds (unless there is a hurricane on its way.


Hope that helps.

Alex

I agree. I lived in a concrete dome home built in the 60s. The second floor was a loft like area that was a bedroom. One area about 25% of ground floor had a kitchenette/bathroomw/a-standupshower because of centralized plumbing concerns no doubt. This was 30yrs+ ago. It was ideal for both the environment, it's impenetrability, & location to the flood paths out there as well as all associated cost savings.


Good luck & Best wishes.....

 

[Masquernom]

Hi Markie,



Good point. However there are several options in Termite prone areas. Several manufactures are injecting insecticide in the foam. In addition, there are a couple of barriers or membranes that work. EPS foam is not a food source for termites also.


Alex

The termites don't eat the foam. They just burrow between the foam and the concrete to get to the upper house. They use it as a hidden pathway so you can't find them. That's been the problem.

 

[lsimpson33]

I owned a home where the walls were all concrete.

One benefit was that the outside noise was very low because of it. I lived a couple of blocks from a small airport (including a university flight school) & National Guard base and never heard a thing!

On the downside, having the interior walls be concrete caused issues when the wireng went bad in the walls and I wanted to install some additional electrical components. It was a huge challenge, costing me extra hours with an electrician as well as some creative solutions to wiring.

Insulation-wise, I didn't notice a difference.

 

[HI Bill]

I have radon mitigation under the styrofoam and concrete floor. Six inches of 3/4 inch rock with 4 inch perferated pipe running through the rock. The pipe is connected to a verticle stand pipe that exits through the roof. I have an outlet in the attic adjacent to the stand pipe where I can add a fan in line with the pipe if I have high radon readings.


I don't think radon through the styrofoam in the ICFs would be a problem. Mine are 2 1/2 inches thick with 8 inches of reinforced concrete in the middle. You can get ICFs with 4 inches of concrete between 2 inches of styrofoam too. I have never heard of radon in the cement if that is the idea.

If radon is present in the ground below a home, and both house types have a concrete slab, and radon vapor intrusion would be the same (without mitigation such as the system described above). The house with the better insulation and less fresh air flow will build up the radon gasses to higher concentrations. The rocks used in the concrete may be a source of radon.

In Hawaii, most of us leave our doors and windows open, and the only typical sources of radon are granite countertops and rock collections!

P.S. I live in a four-story apartment building with CMU block, brick, and concrete. The floors and ceilings are concrete, the exterior walls CMU block, and the interior wall wood. This is the quietest and strongest building I've ever lived in! If I had the $ and wanted to build in a hurricane or typhoon-prone area, I'd definitely build a concrete house. The insulating and noise properties, along with the strength make it worth it! I once had a conversation with a LEED-certified employee (Leadership in Energy and Environmental Design), who thought that concrete shouldn't be used in construction due to its high eco-impact. I asked him to look at the life cycle costs of using concrete versus other methods, and he did. It turns out, that the energy savings over a concrete building's longer lifespan more than make up for the material's eco impact.

 

[dixonge]

re: construction costs, most homes in Mexico are concrete. Also, most homes have no A/C or heat. Those two things go together.

 

[Al in Ohio]

Is radon an appreciably greater issue in a concrete home vs wood framed? Seems like it might be.

I wouldn’t see any appreciable difference if the comparison is to a modern tightly sealed wood frame to the ICF. Biggest factor is the location.

 

[bow-tie]

Some good points shared already regarding building with concrete / ICF (Alex's 7 points had some great insights).

We started our house build in fall of 2014. We did a lot of research before any dirt was moved, and I wasn't doing anything until I was confident our end product was going to be very efficient to heat and cool (we live in a heating climate, but it also gets hot & humid here in the summer).

We had already started down the path of using Structurally Insulated Panel (SIPs). It took us a while to find a contractor comfortable with building with them. Come to find out, he had built his share of ICF houses. We built our basement out of ICF, and I wouldn't have done it any other way. Given the opportunity to do it again, I would have strongly considered building the both basement and main floor with ICF.

ICF may be more expensive. It likely depends on area and contractor. Regardless, because of how it performs, we love it and and it's worth the upfront investment. The soundproofing is great, and it keeps the entire conditioned space very moderate, requiring very little for heating and/or cooling load. Depending on your local climate, it may be expensive for what it provides, but it's certainly worth time to educate yourself and the pros and cons.