Rebar in ICF (Insulated Concrete Form) Walls
Frequently, I get asked what do I need for Rebar in my ICF walls? What sizes and how often?
Compared to conventional foundation walls ICF’s require more rebar. However you can have a 6” thick concrete wall with ICF opposed to an 8” conventional foundation wall in most cases. Therefore the extra rebar can save you 2” of concrete throughout your foundation walls.
Since ICF’s incorporate more rebar and are considered reinforced concrete walls, they will allow you to build a taller wall giving you a higher ceiling height compared to conventional concrete walls.
Concrete is strong under compression loads, but tensile strength is much lower. Rebar for below grade foundation walls with backfill on the exterior face is always installed in the inside third of the wall which is the tension side of the wall. For above grade or Party Wall applications the rebar is typically placed in the middle of the wall.
When you look in the Advantage ICF block you will see rebar clips on the plastic webs that space the 2 layers of EPS. For below grade ICF Walls install your horizontal rebar in clip #1 on the first row of block and #3 on the second row and alternating between #1 and #3 for all the sub sequential courses of block. Staggering the rebar from row to row creates a “weave” effect that enables the horizontal rebar to cage (another term “hold) works also)your vertical rebar in place. Vertical rebar is installed once the wall is at full height.
Jobsite tips for rebar:
Make sure you know where on the jobsite you want the rebar unloaded.
Keep the rebar as clean as possible from dirt and other contamination as this will affect the performance
Have a proper rebar cutter and bender on site or arrange to have this done for you prior to having the rebar delivered to achieve required tolerances.
Cut 4 foot lengths and pre-bend them for corners and T-Walls
Place plastic caps over the top of vertical rebar sticking out of footings or walls to prevent injury from sharp ends .
You can click the following link to find out what rebar you will need for your job.
It is critical to review all applicable building codes and ICF manufacture’s engineering, technical manuals as well as CCMC Reports to understand the proper spacing and sizing requirements of rebar.
Coming Soon: How-to do a “T intersection” with the Advantage ICF system!