Air Seal Walls with Simpson Deflector Screws
Today, we’re showcasing how to air seal for interior non-load-bearing walls, specifically involving Simpson Deflector Screws. This process helps prevent air leaks from conditioned spaces into unconditioned attic spaces.
The Problem with Air Leaks and Deflector Screws
A few weeks ago, we discussed how Simpson SDPW Deflector Screws eliminate squeaks in floor and roof trusses. However, they can leave an air-sealing challenge.
Deflector screws require a 3/8-inch hole in the plate to allow movement. This creates an opening where air from the conditioned space can escape into the unconditioned attic. Proper air sealing is essential to prevent air leakage while maintaining the screw’s functionality.
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Air Seal Using ZIP Stretch Tape
To solve the air seal issue, we used ZIP Stretch Tape. This highly flexible, 3-inch tape works well for windows, air barriers, and more.
- Application Process:
- After installing the deflector screws, we backed them out slightly, ensuring they didn’t extend beyond the top plate.
- We applied the ZIP Stretch Tape over the plate, wrapping it on both sides.
- Benefits of Stretch Tape:
- The tape remains flexible, allowing the screw to move as designed.
- It prevents air leakage through the hole.
Reinforcing with ZIP Liquid Flash
To enhance durability, we applied ZIP Liquid Flash over the stretch tape and around the screw. This additional layer anchors the tape to the screw. It also prevents the screw from creating a larger hole in the tape over time due to movement.
Ensuring a Continuous Air Barrier
Beyond sealing the screws, we used ZIP Tape and Tyvek or Myrex to create a continuous air barrier.
The ZIP Tape was applied over the stretch tape, extending up to the ridge and down the opposite wall. This method ensures a tight seal, eliminating reliance on drywall for air sealing.
Adjustments for Door Openings
In areas like bar door openings, where screws weren’t long enough, we modified the process:
- Countersinking:
- We countersank the plate about ¾ inch to allow deflector screws to function correctly.
- Using Longer Screws:
- We used 10-inch FastenMaster TimberLok screws for additional length and strength.
- The screws were fitted with sleeves to maintain movement while sealing.
Applying the Solution Throughout the Home
We applied this air-sealing detail to all interior non-load-bearing walls that connect conditioned spaces to unconditioned attics. Deflector screws were used on all non-load-bearing walls, including those on the first floor with floor trusses.
In Conclusion
This air-sealing solution effectively prevents air leaks while maintaining the functionality of Simpson Deflector Screws.
Request a project consultation if you need help building a custom home, ADU, or whole-house remodeling. Take a look at our comprehensive collection of similar videos on our YouTube channel, The Real Property Show.
