I am building a garage, and most of the block will be below grade. The last one I built I tried surface bond cement, but got nervous and filled the cores with concrete and rebar anyway. So now I am thinking…
Why use the surface bond (which is quite expensive), when I can stack and pour and be done? I am slow as molasses at mortar work, and the last stack job went fast! I’ll use 10″ block for my buried walls up to the bottom of the slab, and 8″ block above, shimming with brick ties occasionally to stay plumb.
Is this method strong enough? (it seems stronger than mortar to me) Any cautions? (other than it might look terrible)
Replies
Whaeeel neow...
First - this IS FINE Homebuilding's forum, not the Fudgeritalittle Horse Barns forums...
but, keeping all that in mind
;)
Since this is a garage and will have infill, all other things being proper and equal, these walls do not need to resist any lateral loads of soils pressing on one side or another. You have equal amt of soil and load - more or less, on each side of the wall, so it should have equilibrium. All the loads on it would be in the verticle plane - the building weighting downward, and the ground resisting upward. So the far more impoortant consideration is that you have good undisturbed soils and a footing with plenty of rebar in it.
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Didn't he say that most of the block will be buried? Did he say on both sides?"But I say to you who hear, love your enemies, do good to those who hate you, bless those who curse you, pray for those who mistreat you.... and just as you want people to treat you, treat them in the same way."
Thanks, Piffin for the quick response - while this discussion may be FINEhomebuilding, this project has a POOR boy building, and I'm looking for where I might save $ to use in other, visible areas, and I certainly want to do things well & permanent everywhere--thats why I'm asking.
Since it will be below grade, I really only care about structure, and my hunch is I am improving that. The only visible block will be a 3 block high section on the back of the garage. BTW footers are on undisturbed clay, 12"x24" w/ 2 pieces #4 grade 60 rebar continuous.
I guess another way to look at it is I am using block as cheap, quick concrete forms in some regard. I could be swayed, but a quick, rough cost comparison makes me lean toward no mortar. Other thoughts?
Edited 5/17/2005 6:19 am ET by Brian
You got frost heave? No rebar/no concrete = lift blocks off footer.
SamT
It's certainly easy to drop vertical rebar down through the cores, to resist most forces in a basement-like wall (so long as the bottom and top are braced). Horizontal rebar is harder to do without special block (and I recall that the block used in Denver had cast-in notches for the horizontal rebar).
Other thoughts?
Yup. There's a reason you don't just plywood form the walls, call in the readymix truck and be done with it? What you're proposing looks neither cheaper nor easier. PAHS Designer/Builder- Bury it!
So I'll run some #'s, but I think either surface bond or stack and fill (or some combo) saves me 50-66% over calling a mason, and I can start right away. Although Piffin nearly shamed me into making the call. As a bonus the last walls I did this way didn't crack, but most buttered walls eventually have a staircase crack somewhere. I am leaning toward surface bond and some filled cores...
Frost heaves are absolutely not a problem (western MD, 9 feet underground).
VaTom, I have done plywood formwork before, no thanks.
Thanks for all the advice
I did see this done in Denver about 10 years ago, on an H4H project. The blocks used were special, with tongue-and-groove edges so they dry stacked better. The concrete was placed with a pumper. Goes real fast.
I lay them in mortar, add bar horizontally and vertically inside, and then pour most of the cores.... but I like overkill if I really want something of lasting value.
I wasn't clear: Will these walls be partly buried on the outside, or will they only be buried below a relatively level perimeter grade?
As far as the possibly ugly exterior goes, you could always add rigid foam and stucco later.
"But I say to you who hear, love your enemies, do good to those who hate you, bless those who curse you, pray for those who mistreat you.... and just as you want people to treat you, treat them in the same way."