[Greenbuilding] [BULK] Re: [BULK] concrete vs block vs ___foundation wall

[Reuben Deumling]

I like the idea of using concrete blocks, and not using mortar seems fine,
too. And I'm particularly fond of getting around building concrete forms. So
far so good. What I keep hearing conflicting opinions about is whether I
have to fill (all?) the voids with concrete and rebar, just some, or whether
I can or should put, say, some loose fill insulation into the voids? Any
thoughts?

Also how does this concrete block approach compare with more advanced
systems like rastra or polysteel? I imagine it is cheaper, but are there
other differences worth keeping in mind?

I would like to minimize the use of concrete (because of its energy
intensity) and I would like to imagine that the system for my 3' high
basement walls wouldn't cost too awfully much in materials.

Reuben Deumling

On 10/10/06, Bruce Donelson <abetterbuilder at frontiernet.net> wrote:
>
>
>
> -
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> I was rather fascinated,
> because the proponents were saying that the walls go up faster, have
> more shear strength, and are easier for the DIYer to accomplish than a
> conventional mortar joint.
>
>
>
> A dry stacked wall might be a tad stronger than a wall with mortar joints.
> You can kick either of them over. All the strength in a block wall comes
> from vertical and horizontal rebar surrounded by concrete.
> Not every cinderblock is made to exact tolerances. A dry-stack wall offers
> no ability to straighten out a wall as you go, which is fairly easy if you
> tap a block down into a mortar bed. If any block in one of my foundations
> is
> out of level by more than 1/8 inch, we will shim the plates to be sure the
> foundation is level. It would be hard to adhere to that degree of accuracy
> with a dry-stacked system.
>
> IMHO the best use of that technique would be for block walls that don't
> require accuracy, particularly if they would be stuccoed. They would still
> require grout for strength, unless they were only say 3' high and not
> likely
> to injure anyone if they fell over.
>
> Bruce
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>