Have a question about my ICF foundation walls. I am preparing to pour this coming Friday, the 23rd, and we spent all weekend putting up bracing and placing door and window bucks (it’s a walkout). Two things suited me fine – the squareness (diagonals were out by less than an eighth inch) and plumb (everywhere we checked, dead nuts). What didn’t suit me was the straightness of the walls and the perception of how level it appeared to be.
We strung each wall and measured with mason’s blocks, and the wall was straight as an arrow according to the tape. However, I could *see* ripples in the wall, where some of the individual ICF’s seemed to have a slight curve to them. Also, the footing was within 1/4″ of level all around – that, of course, seemed to transfer to the top of the wall.
What’s the standard for a conventionally formed foundation? Is it too much to expect perfectly plumb, level, straight walls, or am I being seriously a*** retentive here because (a) it’s my own house and (b) I have no clue what concrete crews typical tolerances are? For you framers, what’s the most you’re willing to see a concrete wall out of plumb or square, or vary in elevation from one point to another, before you say it’s c-rap?
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I can't say just why you are anal retentive, but within a half inch in the levelplane and 3/4" in the diagonals is fine.
And it can change while youare pouring too. Heck, you might get a windstorm between now and thjen. Watch the weather reports, fast, pray, and offfer up a virgin sacrifice every night for the next week, sprinkling their blood on the corner footings..
;)
But where you see waviness in the forms is natural. when they are filling up, they will pouch a little stretching tight the expand whalers that are integral to each block.
Laying in the bottom course is the place to get rid of any swale in the elevation being of. You could have shimmed att he low spot, and then sealed the gap with spray foam from cans, which would also help glue the forms down against uplift.
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Having only worked with conventional forms, I have always wondered the same things about ICF. When we shoot grade at the top of our forms, we will try to be within 1/16". Granted, when you're troweling off, you can't be that exact, but I would be unhappy if the wall levelness were off a 1/2". (1/4" +/- on a horizontal plane?) Doesn't that mean you'll have a 1/2" stack of shims at your low point unless you do some chipping?
When I've seen guys pour ICF foundations on TV shows, the most vibrating that is done makes use of a 2' 2x4 lightly tapped on the side of the walls. We'll still get rock pockets vibrating and beating walls with rubber hammers. I think a vibrator would blow out an ICF wall. I guess if you pour an 8" slump it's no big deal...but I claim to know very little about ICF.
How much steel did you have to put in your walls?