How to Insulate Your House The Right Way – Exterior Insulation

Foreword by Ian Thompson, Editor

From my perspective exterior insulation is far better in so many ways than interior insulation. It’s easier to install, and generally performs much better.

Exterior insulation should be the insulation method of choice for high-performance builds. I would also like to see building codes reflect this as a viable alternative to ‘in’sulation.

Difference between interior insulation and exterior insulation

The main difference between the two lies in where the insulation is placed. Standard insulation is placed within the structure of the house (in the walls, ceilings, and floors), whereas exterior insulation is added to the outside of the house – a bit like wearing a coat.

Both types of insulation serve the same overall purpose, which is to help regulate the internal temperature of the house and improve energy efficiency. However, they differ in terms of installation process, cost, and potential benefits such as aesthetic improvement and weather protection provided by exterior insulation.

How To Do Thick Exterior Insulation by Matt Risinger

Video Summary

1. Material Details:
   • The Atlas Energy Shield XR panels are lightweight and feature a foil facer on one side and an orange facer with logos on the other.
   • The panels used are inch and a half thick (38mm), with an thermal R10 rating per panel. Two panels are used to achieve a 3-inch thick layer, resulting in R20 insulation. This is considered as a high performance thermal blanket wrapped around the house.
2. Seam Staggering:
   • To prevent continuous seams between the two layers, which could lead to air leakage, the panels are installed with staggered overlapping seams.
3. Pre-Installation Wall Preparation:
   • The Zip-R System sheathing is the primary air and water barrier. Before installing the exterior insulation, the wall is checked for any areas needing sealing with liquid flash products (or insulation sealing tapes) to ensure airtightness.
4. Window Installation:
   • The exterior insulation install showcases two methods for window installation to accommodate the thick insulation. One involves creating a buck to bring the window forward, flush with the insulation, while the other keeps the window set back (recessed).
5. Soffit and Roof Insulation:
   • Matt explains the unique detail of running wall insulation up to the roof sheathing, eliminating exposed rafters and creating a continuous exterior insulation barrier.
6. Installation of Insulation Panels:
   • The panels are attached using specialized Spax screws and caps, ensuring they remain secured until the rain screen and siding (cladding) are installed.
   • A rain screen, consisting of 1×4 inch battens is installed to create an air gap behind the siding for water drainage, air flow (drying), and enhanced durability.
7. Bug Screen Installation:
   • A bug screen is installed at the base of the insulation to prevent pests from entering, highlighting the importance of this step for long-term effectiveness in the USA.
8. Cutting and Handling Panels:
   • The panels are cut using simple tools like hand saws, similar to working with drywall, emphasising the ease of installation by relatively unskilled builders.
9. Benefits of Exterior Insulation:
   • Exterior insulation keeps the house’s structural components warm, minimizing condensation risks and enhancing energy efficiency.
   • The exterior insulation adds to the house’s durability and healthiness by helping prevent excess moisture-related issues.
10. Product Characteristics:
    • The Polyiso insulation used is noted for its low global warming potential (manufacturing process and elements) and versatility for both above and below-grade applications.
    • The use of a radiant barrier on the aluminum facer further enhances energy efficiency, particularly in hot climates.

Conclusion

This exterior installation process is efficient, with the building crew making significant progress in a short period of time. The combination of exterior insulation and rain screen provides a robust and efficient system for protecting the house from the elements. Matt concludes by reinforcing the benefits of exterior insulation in both northern and southern USA climates, emphasizing its contribution to energy efficiency, durability, and overall building science performance.

Related

Benefits of Exterior Roof Insulation

Crafting a Sustainable Home: Construction Insights from Framing and Exterior Insulation – Real Rebuild Episode 2

Tag: exterior insulation

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