Insulated concrete form (ICF) installers must master the installation of the ICF wall alignment bracing system to ensure the success of the ICF wall project. ICF bracing systems align the wall before pouring the concrete. ICF bracing also allows the installer to plumb the walls immediately after pouring the concrete. The bracing system is critical as it protects the poured wall from wind and other lateral loads until the concrete has fully cured. A properly applied ICF bracing system ensures worker safety, as well as straight, level, and plumb ICF walls.
Planning, Preparing, and Materials for ICF Bracing
How to Determine the Number of Braces for a Jobsite
Determining the number of required braces for a project depends on the spacing of the braces. Several factors determine how to space the ICF braces; however, they are typically five or six feet apart. The spacing of braces must meet safety codes.
The spacing of ICF bracing should achieve the following:
- Align the ICF walls
- Withstand wind loads on the ICF wall
- Prevent leaning walls
- Withstand concrete pressures during the pour
- Accommodate the lengths of scaffolding planks
The areas near the door and window openings, on the corners, and the T-intersections may require extra bracing
Materials Required to Install ICF Bracing:
- 2-inch X 4-inch dimensional lumber for uprights, rails, tow board, lateral braces, and wood form guides.
- 2-inch X 8-inch wood planks for standing surface.
- Steel turnbuckles to adjust wall to a plumb vertical surface once anchored.
- Strongbacks – 18 gauge steel studs ranging in sizes of 8 to 12 feet tall.
- Scaffold bracing brackets.
- Materials for anchoring turnbuckles to soil or concrete: a 3-foot long #5 rebar, Tapcon® concrete screws, or a 2-inch by 6-inch wood plank and low expansion spray foam adhesive.
- 2-inch #10 or #12 pan head screws for securing wood planks to scaffold bracing bracket.
- 1.5-inch #10 or #12 pan head self-tapping screws for attaching strongback to ICF block.
- 1.5-inch #10 or #12 pan head self-tapping screws for securing scaffold bracing bracket to the .
- 1.5- inch #10 or #12 pan head screws to attach to 2-inch by 4-inch uprights and lateral brace support to scaffold bracing bracket.
Assembling the Five Basic Components of an ICF Bracing System
Turnbuckle alignment bracing is the industry’s standard for ICF bracing. Typically, contractors place the bracing system after three courses of ICF block before it becomes difficult to install the horizontal rebar or stack additional courses of ICF block. However, exceptionally windy weather may require assembly of the bracing earlier in the stacking process.
Assembling an ICF bracing system in five steps:
- Strongbacks, typically made of steel or aluminum, are the vertical upright sections of the bracing system that are directly attached to the ICF wall. Strongbacks come in various lengths (8 to 12 feet) with slots spaced vertically along their length.
Place the strongback against the wall and fasten to the form’s furring strip using 1.5” #10 or #12 pan head self-tapping screws. Never over-tighten nails or place at the bottom of the slot because this causes the alignment system to work against a straight and plumb wall.
Insert the screws at the top of the strongback and leave the screws slightly loose. The screw must be loose because after placing the concrete, the foam settles which causes the screw to travel downward. Placing the screw at the bottom of the slot does not allow it to move downward. The resulting pressure from the screw not moving transfers to the brace. This scenario makes the wall difficult to align and may damage the bracing or cause the wall to bow.
- Attach scaffold platform bracket into the slots of the strongback. Secure the platform bracket to the strongback with 1.5-inch #10 or #12 pan head self-tapping screws. The wood plank walk boards sit on top of the brackets and attach using 2-inch #10 pan head. According to OSHA, the walking platform must be a minimum of 18 inches wide and rated to support equipment and workers. Also, walking surfaces more than 10 feet above grade must include a toe board.
- Footplate: Fasten the footplate or anchor foot securely to the ground by staking with a 3-foot long #5 rebar into dirt or sand. For concrete floors, attach the footplate with Tapcon® concrete screws. If you can’t use concrete screws, glue a 2-inch by 6-inch wood plank to the floor using low expansion spray foam adhesive.
- Turnbuckle (leg kit, outrigger): The turnbuckle extends at an angle from the platform to the footplate, securing with 1.5-inch #10 or #12 pan head screws. The turnbuckle also contains an adjustment mechanism that makes it easy to plumb the wall, even after filling with concrete, by simply turning the threaded shaft and adjusting its length.
Attach or insert a safety rail into the bracing system. The OSHA required safety rail, protects workers from falling off the wood plank walk boards. Importantly, the safety rails of a scaffold, whether supported by a frame structure or ropes, must have a minimum of 200 pounds top rail capacity. The final working height should be sufficient to safely place vertical rebar, inspect the wall cavity, safely pour an ICF, and internally vibrate during the pour.