Sorry if already discussed.... Basic question: Is there a "preferred size" for the vibrator head? Details: I'm going to build an ICF home in the spring of '22. Rancher with 9' basement walls (10" in thickness) and 9' wall for the main living floor (6" thickness here). I'm going to buy a "backpack" electric vibrator with a long whip and a head.... I was thinking about an 11' or 14' whip (I'll (or my helper will) be standing on the scaffold...) The heads for these vibrators can be had in 1" to 2.5" size/diameters. Does anyone have a reason to pick one versus the other head? Even the large one (2.5") will fit in an 8"x6" cavity pretty easily, rubber coated might make sense for plastic separators of the ICF forms... advTHANKSance, Chessie

Go with a 3/4" to 1" head diameter. The larger sizes will place excess pressure on the forms and are not needed for proper consolidation.

You could also ask your ICF supplier this question. Based on your chosen brand of ICF they may have different suggestions for size/type of vibrator, concrete mix (slump/aggregate size), etc. to ensure concrete is properly consolidated.

Totally disagree a 3/4" head has an area of influence of 5" and a compaction rate of something like 4 yds per hour. So unless your poring concrete out of a hand mixer, it won't work. Minimum 2" is required. Go to the Oztec website and go on the second page. It gives you the specs. on different head sizes.

Just checked. Oztec, hit the products tab. Then the next page go on the selection listing and travel to the bottom of the page for the specs. 3/4" will do a grand total of 1-3 yds per hour. I wouldn't use a back pack unit. An electric will work better. Either way your going to need 2 people on the vibrator. As you see in the chart, a 2" head needs to be dropped every 17" to be effective. With the heights your pouring you will do it in a minimum of 3 lifts. So it works out to 423 drops for a 200 lin ft pour. Hopefully you have some real good friends to help you. The vibration makes or breaks the job, also it's the hardest part of the pour.

Thank you for the input. I was planning to vibrate every third "chamber" (8" between plastic spacers), in other words, I'd be vinrating every 16"-24". (The NuDura installation manual mentions vibrating every 2', so I was going to be under that. But they have no guidance on sizing of the head, thus my question.) And yes, to confirm your posting, I was planning 3 "lifts", each approximately 3' tall. Again thanks. You mention Oztec... Does anyone have an opinion on their "pencil head" shaker/vibrator? One wouldn't use that *instead* of an insertion vibrator would they? The thought is great if you could avoid all that internal insertion and removal of the whip... but I'm skeptical of the "instead of"....But I'll do what works best, even if it makes me very tired and sore! Chessie