ICF interior wall connection

[DianeP]

Does anyone know if the interior walls that meet with inside corners of an ICF wall have to meet up at the cement center?  I have always had it meet at the styrofoam outside edge when I drew plans for the other ICF homes I have done and no one has ever said anything was a problem.  This plan was drawn by someone else and I am helping clean it up. I think it doesn't have to meet this way, but I want to make sure. 

 

[rlackore]

It doesn't have to. The only scenario I can think of where it would be absolutely necessary is if the interior framed wall was being used for lateral load transfer, in which case you would probably want to be in line with the concrete core of the ICF. Because the embedded webbing in an ICF generally runs vertically, it's common for an interior framed wall to not align with the webbing (which you can screw the end stud to). And, depending on the manufacturer of the ICF, some corner units have a vertical web just on either side of the corner, so problem solved. The framer can always brace the wall to the floor or roof/ceiling.

[robdyck]

8 hours ago, DianeP said:

Does anyone know if the interior walls that meet with inside corners of an ICF wall have to meet up at the cement center?  I have always had it meet at the styrofoam outside edge when I drew plans for the other ICF homes I have done and no one has ever said anything was a problem.  This plan was drawn by someone else and I am helping clean it up. I think it doesn't have to meet this way, but I want to make sure. 

 

For simple interior finishing, line the wall framing up with the interior of the ICF wall so that they are flush.

[DianeP]

49 minutes ago, robdyck said:

For simple interior finishing, line the wall framing up with the interior of the ICF wall so that they are flush.

 

Thanks for the confirmation Robert.  That is what I normally do, but this had me second guessing myself.  

[DianeP]

2 hours ago, rlackore said:

It doesn't have to. The only scenario I can think of where it would be absolutely necessary is if the interior framed wall was being used for lateral load transfer, in which case you would probably want to be in line with the concrete core of the ICF. Because the embedded webbing in an ICF generally runs vertically, it's common for an interior framed wall to not align with the webbing (which you can screw the end stud to). And, depending on the manufacturer of the ICF, some corner units have a vertical web just on either side of the corner, so problem solved. The framer can always brace the wall to the floor or roof/ceiling.

Great info!  Thanks so much for the details on how this is done.  Now I have an answer for the client, should he question me on having moved the walls.  

[robdyck]

1 hour ago, DianeP said:

 

Thanks for the confirmation Robert.  That is what I normally do, but this had me second guessing myself.  

You're welcome. FWIW...I have tons of experience with ICF foundations and homes; designing them, building them, living in them.

[GeneDavis]

It's a minor detail, but when joining wood framing to ICF walls, there is always the need for the tie.  Here is what I have used for every ICF job I've drawn or built:  https://www.mudsupply.com/Simpson-ICFVL-p/909200743.htm?gclid=Cj0KCQjws536BRDTARIsANeUZ58jqTmNY-3U99byqV-Q1GVhS8QVnG-AqSDe_2HO6Uk7Gt99nHk3iz8aAlBdEALw_wcB

 

The ears of the plate go through the EPS foam and into the core area, where the poured concrete then locks to the insert, and this provides fastening for the 2x4 end stud that sisters up against the ICF wall.

 

Placing something like this at a corner isn't quite possible, flush out to the corner where it is needed, but I could imagine the plate being able to pick up about an inch of the stud's edge for fixing that side, and then using some strapping for the other side, strapping back along the adjacent ICF wall to some "nailing" points.

[rlackore]

1 hour ago, GeneDavis said:

It's a minor detail, but when joining wood framing to ICF walls, there is always the need for the tie.  Here is what I have used for every ICF job I've drawn or built:  https://www.mudsupply.com/Simpson-ICFVL-p/909200743.htm?gclid=Cj0KCQjws536BRDTARIsANeUZ58jqTmNY-3U99byqV-Q1GVhS8QVnG-AqSDe_2HO6Uk7Gt99nHk3iz8aAlBdEALw_wcB

 

Gene, I've specified those frequently for ledger connections but have never considered using them for interior framed walls - it's an interesting solution. Simpson doesn't publish a lateral load capacity in the 'F2' direction, otherwise, these could be used to brace interior framed shear walls instead of cutting back the form. Thanks for the tip.