Homeowners and builders in Edmonton often ask if insulated concrete form (ICF) blocks can be placed on top of an existing slab or foundation. The short answer is yes — it’s possible and often practical when the existing concrete is in good condition.
Assessing the Existing Slab or Foundation
Before placing ICF blocks, it’s important to confirm that the existing concrete foundation or slab is structurally sound and level. Any cracks, uneven spots, or signs of movement should be inspected by a professional. The weight of the new ICF wall system must be calculated based on the bearing capacity of the soil and the design load of the structure.
Preparing the Surface
Start by cleaning the concrete surface thoroughly and removing debris or loose material. Apply a suitable bonding agent or waterproofing layer if required by design. Anchor bolts or rebar dowels can be drilled and epoxied into the slab to tie the new ICF wall securely to the existing structure.
Installing ICF Blocks
Once the base is prepared, the first course of ICF blocks can be placed directly on the slab. Use a laser level to ensure the blocks are perfectly aligned, as accuracy at this stage will affect the entire wall height. Seal the base joints properly to prevent water intrusion and air leakage. Builders in Alberta commonly use 8-inch ICF core walls for above-grade or load-bearing applications.
When to Consult a Structural Engineer
In cases where the existing slab wasn’t originally designed for additional wall loads, consult a structural engineer. They can evaluate soil bearing capacity, footing width, and reinforcement needs to ensure safety and code compliance. This step is especially important for commercial ICF builds or multi-storey residential projects.
Conclusion
Building ICF walls on top of an existing concrete foundation is a practical option when properly evaluated. With correct preparation, alignment, and engineering review, homeowners can enjoy the strength and energy efficiency of ICF construction in Edmonton without starting from scratch.
Get an ICF quote from YEG ICF to discuss your next foundation or wall build.