I am getting ready to attach my sill plate to the top of my basement wall.  I already have 1/2" anchor bolts set every 4' in the top of my 9'+ basement wall.  I was going to apply a couple of beads of construction adhesive between the sill plate and the top of the concrete prior to tightening the anchor bolts down to help fill in any minor voids in the concrete but I got to thinking about Gorilla glue.  It is moisture activated polyurethane glue that sticks to just about everything and expands during the curing process.  Why not apply a thin coat of Gorilla glue to the back of the already moist treated sill plates and then bolt it down?  Cost wise it is a approximately the same for the amount of Gorilla Glue I would need vs. the amount of PL Premium in 28 oz tubes.  While both glues are considered waterproof, the gorilla glue would provide a continuous waterproof barrier between the concrete and wood while the construction adhesive would only be intermittent unless I put at least 4 beads of the stuff down.  If I use the Gorilla Glue I was also considering using untreated sill plates since they would be completely protected from the moisture in the concrete.  This avoids any concerns with fastener corrosion when the floor trusses are attached to the sill plate.  Thoughts?

Sealing the gap between concrete and sill plate is the purpose for 6" sill seal foam. Use it. Faster, not pricey, and provides a good barrier between the concrete and the wood of the sill plate.

Arkie, I thought you were going up with 6" forms on the second level?

I'm with dmaceld on this one. I don't see the point in adhesive and the foam sill sealer should do the trick to protect the wood and eliminate air leaks, and some copper to help keep the bugs out.

I am continuing up with 6" ICF walls above the 8" ICF basement walls. The 2x4 plate I am referring to sits on the inside edge of the taper top basement forms and is secured to the top of the basement wall with anchor bolts every 4'. My top hung open web floor trusses will rest on top of this plate and be secured to it. Air passage underneath the plate is not a concern since there will eventually be 6" of concrete enveloping the outside of this plate. I guess one concern was possible moisture transfer from the concrete to the wood sill but I was also concerned with shrinking and possible warping of the plate if only secured to the wall every 4' with the anchor bolts. The thought was that construction adhesive or Gorilla Glue between the 2x4 plate and concrete would resist any twisting or shrinkage of the 2x4 as it dries and would reduce the possibility of any squeaks in the future. The Gorilla Glue also provides a continuous moisture barrier between the concrete and wood.

Posted By arkie6 on 10 Aug 2011 12:10 AM
The thought was that construction adhesive or Gorilla Glue between the 2x4 plate and concrete would resist any twisting or shrinkage of the 2x4 as it dries and would reduce the possibility of any squeaks in the future. The Gorilla Glue also provides a continuous moisture barrier between the concrete and wood.

With a bolt every 4' and the weight of the trusses I wouldn't worry about warp & twist in the 2 x 4. I don't think there would be enough to cause any problem.

The foam sill seal will provide a moisture barrier also, in fact I would trust it to have better integrity than glue smeared on the concrete.

Wood and concrete shall not touch (unless P.T.)

So unless you are slathering this glue really thick on the entire piece of wood I would recommend the standard sill gasket

Arkie, I'm curious on your design. Since there's only two inches of difference between the 8" block and the 6" block, and minus the 1/2 of foam on the 8" block, that would leave you only 1-1/2" of concrete for your sill. I know most top bearing trusses want 3-1/2" of bearing. Also, aren't you concerned about the structural integrity of the "ledge." I was talking to one block manufacturer about using their brickledge as a ledger for top bearing trusses, and they said it wasn't designed to deal with vertical and lateral loads and that they were surprised to see some manufacturers displaying this as an option on their blocks.

Posted By jeepster on 10 Aug 2011 08:28 AM
Arkie, I'm curious on your design. Since there's only two inches of difference between the 8" block and the 6" block, and minus the 1/2 of foam on the 8" block, that would leave you only 1-1/2" of concrete for your sill. I know most top bearing trusses want 3-1/2" of bearing. Also, aren't you concerned about the structural integrity of the "ledge." I was talking to one block manufacturer about using their brickledge as a ledger for top bearing trusses, and they said it wasn't designed to deal with vertical and lateral loads and that they were surprised to see some manufacturers displaying this as an option on their blocks.

It is a custom design that I did and had my ICF supplier who is also a licensed Civil Engineer review it.  The "ledge" is reinforced with stirrups spanning the inner and outer horizontal #4 rebar as shown on the attached sketch (it is hard to see because I had to reduce the images to <100 kb to upload here).  Note that this custom taper top form does not extend out nearly as far as a typical brick ledge.

I have a full 3-1/2" for my top chord bearing trusses to rest on.  The 6" portion of the ICF (shown dashed on the attached sketch) will have a short "leg" only ~2-1/4" tall on the first inside course that rests on the top of the truss 2x4s.  The truss and plate wood will be separated from the 6" concrete by 1" of 2# density EPS.

Actually, my original plan that I presented to the truss company for a quote had a 2x12 ledger board anchored to the basement wall.  The truss company provided me with a quote and drawing showing that a 1-1/2" bearing was acceptable for their top chord hung trusses.

Here is a darker version of that sketch that may be easier to see.

I don't see the need for the glue, as you do not need to seal anything (as mentioned with concrete continuing outside the plate). A sill sealer would be easier and cheaper solution to protect the 2x4 from contacting concrete.

I have seen a few installers use acoustic sealant below their sill plates on ICF foundations. They claim it provides a better seal than sill sealer (true if the top of the concrete is not finished entirely smooth). Better than glue, IMO, since it will never dry and keep its seal forever (in a perfect world).

That's a great idea Arkie. I was thinking that you could remove 4-1/2" of foam from the inside first course of the second level to achieve full contact, but what you are doing is pretty much the same. Actually, I don't even know if it would be worth it to add the 1" of eps between the core and the 2x. I'd just wrap the lumber in felt.

IMO, your idea is better than the brick ledge for many reasons. For one, half of the vertical load is transferred to the core of the block, as opposed to the overhanging ledge.

Posted By jeepster on 10 Aug 2011 09:37 PM
...Actually, I don't even know if it would be worth it to add the 1" of eps between the core and the 2x. I'd just wrap the lumber in felt.

I have several 4'x16' sheets of 1" 2# density borate treated EPS left over from my underslab insulation that I will be using for that.  I had the underslab EPS insulation custom made and cut and had to buy two full blanks (~4'x16'x2') of it to get the best price but that was a little more than I needed for under the slab.

Gorilla glue is simply a thicker versio of the same foam you glue the blocks together with. I don't see a need for it there, though when the wall is exterior stick frame on concrete, I use some sort of caulk/ sealant. GG is a good glue, but not a great permanent sealant.
I presume you're using a PT wood sill plate. some sort of barrier between the concrete and plate is always a good practice.
Why not cut the foam and slide the plate all the way flush up against the 6" wall? You'd get a much better bite on the sill plate with the anchor bolts.
Simpson makes some great anchors that angle in toward the wall to develop better. Check them out online.
You can't get those ties in there like that. you can't bend a #3 that sharp. If you do, it's useless. draw it up to scale with a 1 1/2" diameter (I think) bend and see if it fits and gives the clearance you need. The continuous bar outside the anchors is a great idea.

The #3 rebar ties aren't bent as sharp as shown on my sketch. The bends have an inside diameter of ~2" . And the tail on the tie over the outside #4 rebar is ~6" long. They worked or at least they fit where I wanted them. I was able to maintain at least 3/4" of cover over the bend. The concrete is poured. It is what it is now.

Posted By Jerry D. Coombs, PE on 12 Aug 2011 03:35 PM
The continuous bar outside the anchors is a great idea.

Thanks.  It was a pain fishing that piece of rebar through my ICF ties, but I felt that it added quite a bit to the strength of the assembly in that location.

Another idea I had was to take some Simpson CS16 16 ga continous strap and attach a piece ~2' long to the side of each of my floor trusses where it rests on the plate and loop it into the 6" wall area around one of the vertical pieces of rebar and then back around to the other side of the truss and secure it.  After I pour the 6" upper wall this would provide additional support for the floor trusses.  Probably not necessary except in extreme cases, but the cost is relatively low (<$150 for the strap and nails).  I am located in central Arkansas in seismic zone 1 from the maps I have seen (UBC '97), but I am not too far from the edge of seismic zone 2A surrounding the New Madrid fault.  Just a little cheap insurance.

I ended up using F26 construction adhesive between my treated 2x4 plate and the top of the basement wall. Builders around here use if for everything. It worked great. I ran two beads ~3/8" in diameter along the top of the concrete before setting the plate. I got a little bit of squeeze out on both sides and a near continuous layer of the F26 between the wood and the concrete. That plate is securely attached to the wall.

Don't use it to glue ICF foam though because it is a solvent based adhesive and will partially melt the foam.

http://www.leechadhesives.com/F26products.htm

Posted By Jerry D. Coombs, PE on 12 Aug 2011 03:35 PM
 
Why not cut the foam and slide the plate all the way flush up against the 6" wall? 

I scrapped my idea of using metal straps on the end of each truss.  What I ended up doing was cutting ~3"x3" out of the 1" thick EPS over the end of each truss so that the upper concrete pour would be solid against the end of each truss.  Prior to installing the 1" EPS, I cut some 4" wide strips of self adhered flashing (Grace Vycor Plus) to go over the end of the trusses to keep the concrete from actually touching the un-treated 2x4 truss top chords.