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Question from a first-timer: concrete blocks vs. poured concrete

La Na
9 years ago

Hi,
This is my first post here. I've been reading the forum for a while and now it is time to start asking questions. :-) Hope someone can answer them.

It's been 15 years that I'm dreaming about building a custom home. After a year of research, I've finally selected a plan that fits our needs the best. I haven't contacted any builders yet, just want to gather information first and learn as much as I can.

I'm enclosing an image of the house. We plan to build it in northern Florida, so no basement will be added. I would like to have it built with either cement blocks or poured cement with reinforcing bars. I need help deciding which one would be better regardless of Florida weather and humidity.

Also, would poured concrete walls be cheaper than cinder blocks?

Thanks for any input!

Comments (31)

  • live_wire_oak
    9 years ago

    If you are wanting to do this because of hurricane resistance, ICF is the way to go for that. Block may look less expensive up front if you're only considering materials choice, but the labor to lay block will absolutely kill you, and it's weaker than ICF. Either way, that is one expensive house to build. Darn expensive. Especially if you want to do it out of concrete.

  • La Na
    Original Author
    9 years ago

    Hi Live_wire_oak, thanks for your comment. Yes, we're concerned about the hurricanes. Also, I think Florida humidity isn't good for wood.

    I've researched the cost of wood frame vs. ICF and some articles say that the cost per sq.ft. is only $2.50 more than wood. I've no idea if that is true, that's why I'm doing research now.

    This house is 4011 sq. ft. + 3-car garage. I don't know where the excessive cost would come from because I've never built a house before and really don't know much about ICF. Do you have an idea how much per sq. ft. it might cost approximately?

  • lookintomyeyes83
    9 years ago

    Raspberry latte, 'all-in', icf may cost you anywhere from 3-10% more than conventional 'stick framing'. That is a ballpark though, and may be influenced by your need to hurricane-proof.

    ICF doesn't appear to be terribly popular here, so you may want to check with the Greenbuilding talk forum, as they deal more with alternative building methods.

    http://greenbuildingtalk.com/Forums.aspx

  • La Na
    Original Author
    9 years ago

    Naween, thanks so much for the link! I've never heard of that forum, but I see there's lots of good topics there.

    I was also wondering if solid poured concrete walls are better than ICF, and what the cost difference is. I'm not that fond of chemicals, plastic, styrofoam and such, and prefer more natural materials around me.

  • La Na
    Original Author
    9 years ago

    The more I read, the more confused I get. Is ICF the same as solid poured concrete? Sorry for a dumb question, but I'm stuck...

    This post was edited by RaspberryLatte on Tue, Nov 4, 14 at 15:48

  • La Na
    Original Author
    9 years ago

    How about the removable forms? The ones that are removed when the concrete sets. Would this method be better than CFI?

  • GreenDesigns
    9 years ago

    The expense on that particular home comes from the many many corners, elaborate roofline, curved windows, and lots of stone. With the added premium of concrete, are you prepared for a 1M range build?

  • mrspete
    9 years ago

    While I'm not well informed about this type of construction, I can add these thoughts:

    - Saying "only $2.50 more" sounds like pennies, but if your house is 4000 sf, and the ICF is $2.50 more than stick-built construction, you're looking at $10,000 MORE than standard construction. That's a used car.

    - I suggest you read LOTS of information, and not just from people who sell ICF. Obviously their websites will tout the benefits of this type of construction!

    - 4000 sf is a large house. Unless you're talking about an extended family, you do have the option of looking at a smaller place. Not only is "small" cheaper to build, small is less expensive to furnish, to maintain, to pay taxes upon, and to cool in the Florida heat. You may end up choosing between square footage and ICF.

  • robin0919
    9 years ago

    Yes, ICF is a solid concrete wall with insulation on both sides.

  • dekeoboe
    9 years ago

    If you are looking at a concrete house, you might also want to look at precast concrete.

  • mushcreek
    9 years ago

    Structurally, the only difference between ICF and poured concrete is the forms. The ICF stays in place to insulate the home. Either one is far superior to concrete block for structural integrity. In north FL, make sure that the roof structure is built to the highest standards as well.

    Despite the mild climate, a well-insulated house is important, even in FL. Make sure the attic is well insulated, and don't let them put the HVAC equipment in the attic unless the roof deck is well insulated, making the attic conditioned space. Our old house in central FL had the HVAC in the attic, which used to reach 130 degrees.

    I second the recommendation to study and ask questions on greenbuildingtalk. Designing and building my own house, I have discovered that a lot of 'professionals' know little about energy-efficient houses. I had one HVAC contractor try to sell me equipment that was 300% too big because he didn't know how to design a system for ICF construction.

    FWIW, we love our ICF home in SC. Our July power bill was $66 for an all-electric home, versus $300 for a drafty, poorly insulated home in FL.

  • La Na
    Original Author
    9 years ago

    GreenDesigns, we will alter the floor plan and make some of the weird corners straight. Also, we probably have 2-car garage instead of 3 because we don't plan getting a 3rd car and paying extra for a useless space isn't what we need. So, the room above the garage will also be shorter. We want it to be a guest room and there's no need to have that room so big.

    I'll try to post a floor plan.

  • La Na
    Original Author
    9 years ago

    And here's the 2nd floor.

  • La Na
    Original Author
    9 years ago

    Also, we don't want stone on the wall, just stucco. It's the floor plan that we really want in this house that fits our needs very well. I know, it is a rather large house but we're trying to simplify a bit here and there to bring the cost down. 1M certainly sounds a bit steep...

    MrsPete, I didn't realize that the styrofoam stays on the wall! I thought that once the concrete sets, the styrofoam is removed. I guess, the regular removable forms approach would be better as I want more natural materials around us. Too many chemicals out there already!

    Dekeoboe, the precast concrete sounds interesting. If that could shorten the time of construction, that would be awesome.

  • La Na
    Original Author
    9 years ago

    MushCreek, those are very good points too, thanks! I'll definitely take that in consideration.

    This post was edited by RaspberryLatte on Sat, Nov 8, 14 at 21:50

  • La Na
    Original Author
    9 years ago

    I've read a bit about the insulated concrete panels and it sounds really good. Did anyone build a house with ICC Wall (Insulated Concrete Composite Wall)?

    I love the idea that the panels are prefabricated and insulated. Even if it were more expensive per sq. ft., it saves the time of the construction, PLUS there's no need to insulate those walls (more savings on construction time and insulation material). The expanded polystyrene (EPS) foam board is sandwiched between the two layers of concrete.

    The structure of the house is very important to us and we don't mind spending extra on the walls, roof and windows. Everything inside can be upgraded later, if need be (floors, cabinets, even windows), but the structure of the house can't, or it would cost an arm and a leg.

  • Brian_Knight
    9 years ago

    Ive never understood why someone would choose ICF when pre-cast concrete panels are available. I would even prefer traditional poured walls with added insulative sheathing to ICF.

    That homeplan is an energy use nightmare for the most part. Probably 1M to build for quality, especially other than stick framed.

    Be aware that with concrete walls and hurricane resistance, you are over-engineering the walls of your home. Windows, garage doors, foundation ties, and the roof become major weak links if your arent addressing those at the same time.

    Wood does just fine in FL if used in a quality manor. If you have concerns for IAQ, an outdoor air introduction system is the best way of achieving measurable results. Building material specification is minor compared to outdoor air exchange.

  • Gary6958
    9 years ago

    I have ICF blocks. (Insulated Concrete Forms). Any amount for sale.
    Shipped to any country worldwide.

    Size: 50â long (127cm), 10â high (25.5cm) and 6â (15cm) wide
    (with a nominal concrete core of 4â (10cm) ).

    It is the exact equivalent of 4 CMUs (concrete masonry unit) in area and only weighs 1.25 pounds.
    The forms are stacked without mortar and are interlocked like a Lego Set into which reinforced concrete is placed, creating a wall and foundation with a fraction of the labor of conventional CMU. Please email with details of quantity needed. Country to be delivered and target price to: garyjmcneish@gmail.com

  • La Na
    Original Author
    9 years ago

    We're revising the floor plan and many things will be simplified. There will be much fewer odd corners, most will be regular corners, nothing too fancy, and no vaulted ceilings, plus the roof won't be as tall (we don't need a big attic). We also plan to do a lot of things ourselves: installing wood floor, painting the interiors, installing the cabinets, etc. The only things we can't do is building core of the house: the foundation, walls, roof, installing the windows, and plumbing & electricity.

    Does anyone know how much (rough approx.) it would cost to build the core & install all plumbing/electricity would cost for a 4,000 sq. ft. home without a cellar, and using the Insulated Concrete Composite Walls?

  • User
    9 years ago

    Making so many alterations will greatly alter the look and feel of the home. And won't save you that much money either. You might could get that home dried in for 700K with the building methods you propose, but it would be the rare bank (or municipality) that would allow you to finish such a home on your own time scale. Unless you are a 1M + cash build and have construction experience and contacts, you need a different plan. And different construction methods. You're getting out of the residential comfort zone and into commercial territory. Which costs even more.

  • josephene_gw
    9 years ago

    Superior Walls has a good website.
    18888175537

  • tulips33
    9 years ago

    We were talking to a builder that wanted to use superior walls for our basement, but the seams really made us doubt it. If I remember correctly the panels are bolted and caulked together. The caulk had a limited warranty on it which I didn't understand, b/c what are you suppose to do when a finished basement needs to be re-caulked? and are bolts sufficient to hold together a foundation?? IDK Anyway, this builder was just starting out and hadn't done too many basements so it was hard to trust his opinion. So if you are going to go that route, make sure you research it. We didn't research it any more b/c we went with a different builder who didn't use them. We did cinder blocks with concrete and rebar put in them after they were set and that dimple material and tar for waterproofing. It was cheaper than poured concrete here in NC.

  • bus_driver
    9 years ago

    Anyone with any doubts about Superior Walls should use something else.
    I watched the setting of those for two houses before making my decision. The bolts installed when setting the panels hold the walls until the house floor structure is PROPERLY secured to the top of the walls. The basement floor slab keeps the walls from moving in at the bottom and if the builder chooses, the walls are secured to the slab to prevent outward movement for daylight basements. The backfill prevents outward movement at the bottom.
    Thinking things through from a technical perspective is helpful.
    Going on now with 12 years with my Superior Walls and am perfectly pleased.
    Concrete block probably comprises the majority of basement foundation construction and it is the poorest choice in my opinion. But that is not to say that it is a bad choice-- definitely not the best.

  • robin0919
    9 years ago

    I still say look at ICF. Go over to greenbuildingtalk.com and read up on it at the ICF forum. It's not much more than stick building and a much better shell. Also 'much' better in a hurricane.

  • La Na
    Original Author
    9 years ago

    We won't have a basement in Florida, just a foundation.

    What about a solid poured concrete foundation, not cinder blocks? Would that be a good idea for a large house (4,000 sq.ft.)?

    As for the walls, I think we might go with the Insulated Concrete Composite Walls, where the outer layers are concrete and the inner layer is insulation. I really want to go totally without wood because of the termite issue, which is pretty bad in Florida.

    We're still working on the floor plan and might go with a totally different plan, just using parts of the plan I posted above, as I like some details about it.

    Would placing a fireplace in the exterior wall be better than interior wall? Still trying to decide if we need it in the living room, but I would like to have one in the house.

  • bus_driver
    9 years ago

    The ICF that I observed is foam on BOTH sides. And termites have been known to attack the foam. I think the ICF is a good concept, the results being dependent upon the knowledge and integrity of the builder.
    I also suspect that you have not put any effort into learning about this on your own. My idea, and practice, is to take any interesting new idea and intensely research it ON MY OWN.
    There are many suppliers of the ICF.

    Here is a link that might be useful: ICF

  • Brian_Knight
    9 years ago

    Why would you "need" a FP in FL? Interior might be better but center of ridge is probably most important. Best of all: Skip it, you dont really need one, they are expensive, waste conditioned air and introduce combustion gas concerns.

    Termites love to tunnel through foam which may only be a problem if they have access to it and a pathway to wood. Do you have a link of the product you mentioned? Sounds like Mgo SIPS to me which are pretty rare.

    Pre-cast concrete panels dont have to be for basements, people around here are using them for their entirely above grade homes.

  • La Na
    Original Author
    9 years ago

    Brian, this is what I meant for the Insulated Concrete Composite Walls:

    http://www.sipcrete.com/System.htm

    It's the opposite of ICF and the foam is sealed inside the concrete. So, no bugs can get in.

    I love FP, and in the northern FL it does get cold! Sometimes even freezing.

  • La Na
    Original Author
    9 years ago

    Bus_driver, I read about the ICF and people reported leaks, melting, etc. I really would prefer more natural material around me. There are too many chemicals out there already, no need for more!

    Also, foam walls would need siding and sheetrock added, which is extra cost. While with the insulated concrete walls (concrete sandwich with foam inside) all you need is good sanding, primer and paint, or stucco on the outside. Insulated concrete walls look like this:

    http://4.bp.blogspot.com/-kLC_gq_WwMI/UaX2p9tqjzI/AAAAAAAAAQY/qgdGknGmsYU/s1600/animaatio1.jpg

  • Brian_Knight
    9 years ago

    That Sipcrete is an interesting product. I can imagine incredible thermal and structural performance. Certainly not inherently termite resistant without closing off the bottom somehow. It would be nice if they could swap the interior concrete for a metal stud system for typical drywall attachment.

    Good luck with your budget. Unless you can talk to an experienced contractor whose used it and the satisfied customers, I would be leery. Judging from their website, there has been a grand total of one house built so far. Maybe you can talk to Boris in Cyprus.

  • La Na
    Original Author
    9 years ago

    Brian, this website was just an example of what that product looks like. I'm still far from selecting a builder at this stage, just trying to figure out the budget (not that it matters a whole lot, but it would be nice to save something). I'm sure in Florida there are plenty of builders who use something like this since they build lots of houses from concrete (blocks, solid poured, etc.) because those kind of houses are better in a hurricane area.