Attaching Floor Systems to the ICF Wall

The floor system can rest on top of the ICF wall, using a sill plate and anchors. In many situations the floor system is attached to the inside of the ICF wall. There are four methods we recommend for attachment.

1. Attaching the Micro Lam to the ICF with anchor bolts.

Cut (say) 4" diameter holes in the ICF wall which are centered around each anchor bolt. The micro lam is screwed in position at the exact height and anchor bolts installed in position so that they are embedded into the concrete. The advantage of this method is that it is less expensive than ICFVL.

Alternative floor connection detail

The photo below details using anchor bolts with a micro lam ledger board. Notice the use of a poly membrane between the concrete and the ledger board to prevent water damage.

Alternative floor connection detail

2. Using Simpson ICFVL brackets to attach the floor system

The ICFVL is a 14-gauge galvanized steel connector that it inserted through the ICF foam so that the two legs become embedded in the concrete. The legs are sufficiently strong to withstand the cantilevering loads through the foam thickness. The advantage of the ICFVL bracket is that minor adjustments can be made to the height of the ledger board after the fact: it is more forgiving.

Overall labour costs are higher because the ledger board then needs to be attached using the ICFVL-W (wood ledger) or ICFVL-CW (composite wood) and 8 special screws. In addition the ICFVL system is considerably more expensive than conventional anchor bolts. Vancouver ICF stocks the ICFVL brackets.

Vancouver ICF supplies ICFVL and they are always in stock.

ICFVL details

3. Supporting Ledger with Concrete

When substantial loads are exerted on the ledger plate, the engineer may require that the ledger be supported by concrete. This detail allows for the ledger to be directly supported on the concrete without compromising the insulation performance of the top of the foundation (click on image to open up pdf file).

Concrete support of ledger board

4. Stem wall, Narrowed at Top

Often stem walls need to be narrowed at the top so that the ICF foam does not show at the surface of the slab (click on image to open up pdf file).

Concrete support of ledger board