Getting back to the original post - there a few things to consider when screwing into plastic tie ICFs. The type of plastic can make a difference (eg, a polypropylene tie typically has a higher pull-out/sheer strength than a HIPS tie, for instance). Also, weather can play a large part (if you get into cold weather construction, the plastic ties may become brittle and necessitate pre-drilling - especially with a HIPS plastic).

All this being considered, a course thread screw is the best bet. Also be sure the fastener being used is proper for the application (eg, if you are fastening exterior siding, be sure to use a screw rated for wet locations, etc.). As far as nails are concerned - they may be strong by the standards of your own pull test, but I would check with the manufacturer of the ICF and exterior cladding for recommendations, as this may void warranty.

Yes, if there is any risk that the material will crack or split when fastening screws, pre-drilling is appropriate provided you don't oversize the pilot hole for the fastener being used.

Both Hardie Board and BuildBlock approve the use of ring shank nails, but recommend screws for best results. So I am thinking spiral nails would be a great solution. Simpson makes 2x0.120” 21 deg 316 SS spiral nails that seem perfect for this application. We have a 2400 sf BuildBlock ICF single-story house that we are building for ourselves to downsize now that the kids are gone...and before they think about coming back... Of course, it is passive solar cooled/heated, has HR floor heating and has a masonry heater because my husband likes triple redundancy in all things... This house is about one month away from getting its Hardie Board panel and batten, so I think we will try this spiral nail approach given the risk is on us and not one of our customers. Again, thank you Dmaceld!

If you can use spiral nails and get a great result without having to pre-drill and use screws, I don’t think this is off topic. More like answering the question that wasn’t asked, but provides the best solution.

Just to be 100% clear, I wouldn’t recommend using SS fasteners with ICF having steel ties for the aforementioned potential galvanic corrosion concern.

Posted By sailawayrb on 18 Sep 2017 10:24 PM
... so I think we will try this spiral nail approach given the risk is on us and not one of our customers. Again, thank you Dmaceld!

The big challenge is finding them coil collated for a nailer. I bought mine from a local building supplier. Later, when I went to look for some more I couldn't find them. Just for curiosity I searched for them now. This is the only one I found. https://www.amazon.com/dp/B072PZDT93. An alternative that would probably work OK is pallet nails. You probably could use them although the head may be a bit smaller and the end is blunted. I don't know how the blunt end will act going through Hardiplank or the plastic tie. They're great in wood. My dad used to blunt the ends of nails 60 years ago if there was a concern about the board splitting.

Dmaceld, I was considering using these:

Simpson 2x0.120 21 Deg 316 SS Spiral Nails

We have siding coil guns, but we would prefer to use our framing guns...typically less jamming although somewhat heavier gun. I like the fact that your nails have the spiral going nearly to the head. However, with 1/4" panel, 1/4" rainscreen and 1/4" EPS before reaching the beginning of the plastic tie, these should be fine. Funny...my dad taught me how to blunt nails too to reduce wood splitting risk! Anyhow, we have Dennis from the BuildBlock technical side looking into this to provide their "official" guidance/recommendation. I expect that tomorrow AM.

Posted By sailawayrb on 18 Sep 2017 11:59 PM
Dmaceld, I was considering using these:

Simpson 2x0.120 21 Deg 316 SS Spiral Nails

We have siding coil guns, but we would prefer to use our framing guns...typically less jamming although somewhat heavier gun. I like the fact that your nails have the spiral going nearly to the head. However, with 1/4" panel, 1/4" rainscreen and 1/4" EPS before reaching the beginning of the plastic tie, these should be fine. Funny...my dad taught me how to blunt nails too to reduce wood splitting risk! Anyhow, we have Dennis from the BuildBlock technical side looking into this to provide their "official" guidance/recommendation. I expect that tomorrow AM.

Those should work just fine. I did come across some strip collated nails in my search. These may have been the ones on another site.

It'll be interesting to see what BB comes back with. I would really be surprised, and chagrined, if the answer is somewhat negative!

I will certainly post what they say Dmaceld. However, I can't say that I would be surprised if they are not in favor of this approach. Engineers often tend to be very conservative and they sometimes don't like to extrapolate beyond their tested and proven methodology database. And there is good reason for this when protecting public welfare. Of course, the better engineers will get innovative, extrapolate from the known database and then do the testing to improve the methodology... We shall see where we are here.

Posted By sailawayrb on 19 Sep 2017 01:11 AM
  Of course, the better engineers will get innovative, extrapolate from the known database and then do the testing to improve the methodology... 

Since I'm an engineer, and tried to be innovative and open minded when I built my house, I'll put myself into your category of 'better engineers'!

Really, I think builders as a whole are more stuck in a rut and resist changes as much or more than anyone!

The only caveat that I found is that it seems like screws driven at a very high RPM tend to strip, even before they are fully tight. My theory is that the high speed softens the plastic due to the heat generated. I had better results when I didn't run my 1/4" driver at full speed. I don't have a real screw gun. It's amazing how strong that little strip of plastic is. I shot a single siding nail through a board, and hung off of it- 200 lbs.!

Dennis from BuildBlock said they are aware of contractors successfully using spiral nails, but they always recommend a pull-out strength test with actual siding and specific fastener before selecting the specific fastener used for the project. So I take that as official approval to proceed and this seems prudent... I have a couple extra blocks to experiment with to see how the ties like getting spiral nails blasted into them.

I prefer a #9 or a #10 not predrilled. If using an impact, use a 3 speed and use the middle setting. High now a days is too much unless your really good at stopping at right time. Depending upon the block, some ties are softer then others but still work as well. Fox, Reward (now fox) and Nudura seem to be about the same before stripping. Logix are harder, might be the resin or recycled. I’m not a huge fan of the block but the webs are strong. Look at the depth and pitch of the screws it makes a difference tightening up also. A cheaper grip right wood screw has more depth then a grk for example. However unless you want to use several types during the build, a 3” screw with longer threads can be used for the strong backs. That’s another thread for screw head types, lengths and brands preferred to attach strong backs and wood types.

So you see...my statement is factual and Polycrete can't handle truth. This is good discovery post for future class action law suit against Polycrete having knowledge of product problem and doing nothing about it.

Polycrete stands by its original position. The system meets or exceeds all international buildings codes. There are not now and never have been any lawsuits relating to structural issues of any sort. As our XpressWall system makes great strides in market share, some of our competitors seem to be getting edgy. This troll "icfbound" is apparently employed by one of them. Feel free to contact me offline for more information. Bruce Anderson, President -- PolycreteUSA.

I would have no reservations about using Polycrete. But you two get your own thread.