Replies

1. 
   shedworkshop | Feb 07, 2024 09:40am | #1

   Bumping this to see if anyone has advice.

2. 
   BSBot | Feb 16, 2024 07:20pm | #2

   Using Rockwool Comfortboard as exterior, below-grade insulation for a monolithic slab is an excellent choice due to its moisture resistance and thermal properties. In your climate zone, where only vertical insulation on the slab is required, the method of securing the insulation does indeed merit consideration for both effectiveness and long-term stability.

   Securing the Insulation:
   Need for Securing: While the earth can provide some support to keep the insulation in place, securing the insulation to the slab ensures that it stays in position against the concrete, maintaining consistent insulation coverage without gaps that could compromise thermal performance. Over time, soil movement, water flow, or burrowing animals could potentially displace loosely placed insulation.

   Securing Methods: The method you mentioned using zip ties and plastic prong washers penetrating through the vapor barrier into the concrete is one way to secure Rockwool Comfortboard. This approach provides a mechanical attachment that can resist displacement due to external forces.

   Considerations:
   Vapor Barrier Integrity: If you choose a method that penetrates the vapor barrier, ensure that the penetration points are sealed properly to maintain the barrier's integrity. Moisture intrusion through unsealed penetrations can compromise the insulation's performance and potentially affect the slab.

   Alternative Methods: Depending on the specific product and site conditions, other methods may also be viable, such as adhesive specifically designed for below-grade applications and compatible with both the insulation material and concrete. However, mechanical fastening (like the zip tie method) is often preferred for its durability and resistance to environmental variables.

   Manufacturer Recommendations: Consult the installation guidelines provided by the manufacturer of the Rockwool Comfortboard. Manufacturers often provide recommended methods for securing their products in various applications, which can ensure compliance with warranty requirements and best practices.

   Conclusion:
   Securing the Rockwool Comfortboard to your monolithic slab is worth the effort to ensure long-term stability and performance of the insulation layer. While relying on the earth to hold the insulation in place might seem simpler, mechanically securing it provides a more reliable solution against potential displacement. Ensure any penetrations through the vapor barrier are adequately sealed to maintain moisture protection. Always refer to the manufacturer's installation guidelines for the most effective and appropriate securing methods for your specific project.

3. 
   matthew25 | Feb 16, 2024 09:16pm | #3

   Here is a non-bot response:
   Lookup Plasti-Grip PMF fasteners.