This document has been created as an addendum to our Air-Shield technical data sheets to provide some additional information regarding the application of transition membranes for rough openings, such as windows and doors.
To remain current in the industry and provide our customers with an economical and user-friendly air barrier assembly, we would like to provide two different application procedures to address the use of transition membranes. The first is the use of our Air-Shield self-adhesive membrane as we have always used, and the second is the use of our Air-Shield LMP vapor permeable fluid-applied membrane. Either of these systems is suitable for various substrates, including concrete, concrete masonry, OSB, plywood, exterior sheathing, and metal surfaces. Following are the procedures that we would recommend to achieve continuity of the transition membrane.
Air-Shield – Self-Adhesive Transition Membrane (to be used with air/vapor barrier materials)
- Condition the area to be detailed using Mel-Prime or Mel-Prime W/B. On exterior sheathing surfaces, ensure that enough primer has been applied as typically two coats of primer are required.
- Pre-cut the Air-Shield for each area of the rough opening to ensure ease of handling.
- Apply the first pre-cut strip at the base of the rough opening by removing the release paper and rolling firmly into place, ensuring that there is a minimum of 3” of membrane extending onto the wall. Also, ensure that there is a minimum of 3” of membrane extending into the rough opening.
- Repeat this procedure for the vertical areas of the rough opening, and finally apply the membrane at the header portion of the opening.
- Ensure all edge overlaps are a minimum of 2” and end-to-end overlaps are 4”.
- Seal all terminations with Pointing Mastic.
- Apply the specified air barrier membrane system on the whole wall ensuringadequate overlap with the transition membrane.
Air-Shield LMP – Fluid Applied Transition Membrane (to be used with vapor permeable materials)
- If applying this system on exterior sheathing, OSB or plywood, ensure that any joints or gaps ¼” or greater are initially filled with Air-Shield Joint Filler prior to
- Apply a minimum of 30 wet mil coat of fluid Air-Shield LMP ensuring that there is a minimum of 3” of membrane extending onto the wall. Also, ensure that there is a minimum of 3” of membrane extending into the rough opening.
- Embed a layer of glass mesh into this first coat.
- While the first coat of Air-Shield LMP is still wet, completely cover the glass mesh with a second coat of Air-Shield LMP at 30 wet mils thick again extending 3” onto the wall and 3” into the rough opening. This will allow for maximum adhesion of the two coats.
- If the substrate is concrete or concrete masonry, the glass mesh is not required. Apply Air-Shield LMP in one or two coats in order to achieve a 60 wet mil thick coat.
Apply the specified air barrier membrane system on the whole wall ensuringadequate overlap with the transition membrane.It is important to review each application as there may be situations that would require either of these procedures to be modified based on the project requirements.
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