The Best Insulation Methods for a Slab-on-Grade Build
By Graham Mann | Published: 11/21/2025
Explore the best insulation methods for slab-on-grade construction, focusing on materials, moisture control, and energy efficiency.
The Best Insulation Methods for a Slab-on-Grade Build Key Takeaways: - Rigid Foam Boards: The most effective option for slab insulation. Types include: - EPS: Budget-friendly, good thermal resistance. - XPS: Better moisture resistance and thermal performance. - Vapor Barriers: Prevent moisture from compromising insulation and causing mold or water damage. - Spray Foam: Ideal for sealing edges and irregular areas. - Mineral-Based Boards: Eco-friendly, durable, and moisture-resistant options like Rockwool(https://www.rockwool.com/north-america/). - Moisture Control: Use methods like capillary breaks, sill gaskets, and exterior waterproofing to protect the slab. Quick Tips: 1. Install a vapor barrier over the insulation to block moisture. 2. Use thicker insulation around the slab's perimeter for better heat retention. 3. Consider pairing insulation with radiant heating for improved efficiency. Cost Considerations: - EPS: $0.50–$0.80/sq ft - XPS: $0.70–$1.20/sq ft - Polyiso: $0.80–$1.40/sq...
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