Concrete Block vs Poured walls


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Old 04-24-08, 12:14 PM
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Concrete Block vs Poured walls

Ok, so here is the deal.. I am building a new home soon, and am having problems deciding between a poured basement or block walls, filled with concrete.

There is no doubt in my mind that poured is the strongest and best of the two options.. But the problem is that I am not sure that I can get somebody to come in and do it with out charging me an outrageous cost just for travel time, etc. I think the nearest concrete plant is about 90 mins..

And I could lay the block myself, (with a little help of course) and fill the cavities with rebar and concrete, probably saving a little money in the long run..

BUT I want to do the best thing.. This basement is going to be a very lived-in part of the house, so it's definitely got to stay dry and hold up.
 
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Old 04-24-08, 02:08 PM
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How are you doing your footers and slab? Unless you are planning to mix and pour yourself (that's a lot of bags of concrete) you'll need a truck anyway. Filling block with rebar and concrete will also eat up a lot of bags, time and energy. Bags of concrete aren't expensive individually, but they will add up if you mix your own.

IIWM I would contact the concrete guys in your area, give them an estimate of how many yards you need and see what they say. Do you have forms available? My guess is that in the long run, poured is your best bet although it may cost more.

Don't forget that time has value. A poured wall goes up a lot faster than a block wall. Sit down and figure the cost both ways but I believe that a properly poured wall is a better choice even if it costs a bit more.
 
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Old 04-24-08, 02:11 PM
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Block reinforced with rebar and ladder mesh is stronger than unreinforced concrete (the standard).

That's not to say it's expedient.
 
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Old 04-24-08, 02:13 PM
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How are you doing your footers and slab? Unless you are planning to mix and pour yourself (that's a lot of bags of concrete) you'll need a truck anyway. Filling block with rebar and concrete will also eat up a lot of bags, time and energy. Bags of concrete aren't expensive individually, but they will add up if you mix your own.

IIWM I would contact the concrete guys in your area, give them an estimate of how many yards you need and see what they say. Do you have forms available? My guess is that in the long run, poured is your best bet although it may cost more.

Don't forget that time has value. A poured wall goes up a lot faster than a block wall. Sit down and figure the cost both ways but I believe that a properly poured wall is a better choice even if it costs a bit more.

Visit the Quickrete site. They have a slab calculator. A 400 s/f, 4" slab requires 225!!! bags.
 
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Old 04-24-08, 03:02 PM
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Concrete Block vs Poured walls

A concrete block foundation can be the same stregnth as a poured basement. A 12" poured basement is out of consideration because of the cost. They can build 22 story loadbearing block walls with 6" block walls, so a basement is no problem.

It is not necessary to fill all of the block cores with grout - only those with rebar in them. Also you never use concrete to fill the cores of masonry. You should use grout that has a slump of 9" to ensure all the cores are filled and the rebar is fully bonded. The extra water will be absorbed by the block and used in the curing. Using concrete will give you a weaker wall.

If your designer hasn't a;ready done it, look at the new IRC (International Residential Code) for thable that tell you how much rebar and what spacing in the walls. Your footing probably do not have to be reinforced. For an 8" thick basement wall, the amount of steel will be about the same.

If you use poured concrete, make sure you use reinforcement to minimize the shrinkage cracks and order 3000 psi minimum concrete with no more than 4" slump. Any more water and you will have the usual poured basement shrinkage cracks.

Normally, you are money ahead if you have the concrete delivered even if it is a small basement. Just think about the time and money to run around at $4.00/gal to rent a trailer, get bags and sand, pick up a mixer and then have to clean and return the mixer. Make sure you have a place to dump the extra concrete since it is tough to move once it has set up.

Dick
 
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Old 04-25-08, 06:27 AM
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Ok, good info..

I think I'm going to find a concrete guy in the area to see if they will give me an estimate on a poured basement. The house plans were drawn up with 10" poured walls.
Then I'll get an estimate on block materials, rebar, etc weigh all of my options..

IF I decide to do block instead of poured, what should I use for horizontal re-inforcement? I've heard of using fencing wire, but do they make something specifically for this?
Also, do they make different sizes of the concrete headers (not sure the real name) that go over top of windows and door openings in block walls?

Ohh, and the basement will be about 52'x40'. Yeah.. I see that could take a long time doing it with about 5 of us..and I would definitely need a truck to deliver..
 
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Old 04-26-08, 01:10 AM
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The horizontal is called ladder mesh... it's heavy wire formed like a ladder. There are some cute variations. Concretemasonry is the authority on this.
 
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Old 04-26-08, 06:40 AM
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one other thing to look into is insulating concrete forms.
Murphy was an optimist
 
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Old 04-26-08, 08:30 AM
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Concrete Block vs Poured walls

Joint reinforcement is not required for block basements because the conditions are relative stable and block are cured before they are laid.

It would not be a bad idea to put some horizontal rebar in a poured basement to minimize the cracks from shrinkage as the concrete is cured in place.

ICFs are usually difficult to justify in a basement cost-wise since insulation below grade is not as important (ground is up to 50 dergrees warmer than the outside air in the winter). Also, ICFs are really not for a DIYer unless you hire someone with experience in bracing and pouring/pumping concrete.
 
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Old 04-26-08, 07:43 PM
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So, say you build a 9 foot wall with concrete block. With the block staggered, will the rebar go down through the cells without any issues? Can it be put in after the wall is completed? Or should you use shorter pieces putting them in as you go up? And should the mortar that is filled in the cavities be filled after every few rows, or every row- working your way all the way to the top?
 
 

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