Contents Overlaying ICFs onto existing frame plans Changing wall lengths and opening positions to match ICF break points Picking the crew Site Preparation Making bucks Setting the first course Corner braces Stacking sequence Setting vertical rebar Aligning and plumbing walls Holding down forms against floating Building a floor deck Concrete placement equipment Pour pattern Pouring a gable end Consolidating concrete Attaching roof members Attaching interior walls to ICF walls Making electrical cutouts Interior finish Attaching trim and fixtures Exterior stucco Attaching exterior siding Miscellaneous

ICF wall construction  starts on a level foundation (footer or slab).  If called for in the design, short rebar (called dowels) will be sticking up out of the foundation to secure it to the wall above.  

dowels placed vertically in foundation

The crew snaps chalk lines to mark the edges of the walls, and may even cut nail 2x4 guides outside the lines.   Guides help align the forms and brace them later when concrete is poured.  Forms are set between the guides.  With tall (8-foot) panels, it is possible to stand the panels on end to create a complete one-story wall.

first story panel installation 

With smaller units, such as blocks or planks, crews work their way around the wall in successive courses, building up one block higher each time.   When the wall reaches the height specified for the first horizontal rebar, stacking stops while the crew lays the bar on top of the ties all the way around the wall.   With the taller panel systems, the horizontal rebar may be slid in at the proper height from the sides of the panels as they are set up.

course-by-course stacking of block units

At doorways, workers build a buck (usually of   2 x lumber) and stand it in place.  Then when they stack it they cut the block as needed to set the blocks right up to the lumber.   At windows they usually stack just past the sill level.   Then they cut out a notch in the foam and set a buck in place there.  From then on they cut the block so it fills up to the buck.  It's also possible to stack up the entire wall, and then cut out door and window openings and slide the buck into place.

Window buck set into the wall's notch

As the height of the courses increases, workers must implement bracing lumber such as strongbacks and kickers.   They may also erect scaffolding to stand on while stacking the highest couple of courses.  Some use scaffolds that sit directly on the bracing, killing two birds with one stone.

bracing and scaffolding in one

The pour for below-grade walls is usually done directly with the chute from the ready-mix truck.  Above grade some form of pump (boom or line), bucket and crane, or conveyor is necessary.  It goes just like a conventional cast concrete job, except for timing.  The crew drops the concrete in lifts of 2-4 feet, working entirely around the wall once, then repeating until they get to the top.

Various pouring methods for different applications

When the top of the story is reached, the crew slides vertical rebar down the cavities wherever it's called for.  If more stories will follow, they will need to attach a floor deck before proceeding.  One popular way to do this is to insert temporary blocks in the formwork, pour the concrete, then when the concrete is hard, knock out the blocks and slide in the joists.

Another way to build a floor deck is with ledger boards.   The crew cuts out a square of foam at deck height every 16 inches or so, then mounts 2x lumber over these cutouts.  The ledger boards have anchors sticking out of them into the form cavities.  When the concrete is poured it locks onto the anchors to hold the ledger securely.  The joists are then nailed to the ledger with joist hangers.

After the walls are complete, electricians install cables and boxes inside. 
They cut grooves in the foam, usually with a router or hot knife.   The boxes are recessed into similar cutouts.

Electrical outlet embedded in the ICF unit
after the pour

Any conventional finishes can go on ICFs.  Outside, stucco goes directly onto the foam.  Nailed and screwed sidings (vinyl, clapboard, hardboard, shingles and shakes) can attach directly to the fastening surfaces.  Or, the crews may attach furring strips first, then the siding to the strips.  Masonry veneers can go outside the wall just as on a conventional wall.    The metal straps to anchor them are pushed through the foam formwork before the pour to lock them into the concrete.

Stone masonry easily attached to the basement level of an ICF home.

Stucco garnishes the fascade of a southwestern restaurant

Inside, the most common finish is ordinary wallboard.  It can be screwed onto the forms' fastening surfaces or glued directly to the foam.  It is also possible to plaster the foam directly, usually with a reinforcing mesh. 

The rest of the house (interior walls and finishes) goes up conventionally.  In the end all the occupants see that's different is greater comfort, less noise, a lower fuel bill, and less vibration.