We've Tried Many Expanding Foam Tapes at Small Planet and Have Found Hannoband to be the Best

With Hannoband we found a way to get longer working time and better blower door tests due to the multiple glue joints that create multiple air barriers across the width of a single piece of tape. Tapes without these glue joints can expand too fast on hot days, leaving you too little time to get a large 300 pound window into the opening. Hannoband’s glue joint slows the expansion of the foam, giving you substantially more time to position the window and get it right.

It's All about the Compression

Since the foam is depending on staying compressed to provide a seal in the gap, it's important to choose the right sized tape. We stock the three basic thicknesses to fit most window applications:

  • Narrow gaps between 3/32" and 3/8" can be sealed with the 3E 64/4-9mm tape.

  • For standard 1/2" gaps, the 3E 64/6-15 will seal gaps between 1/4" to 5/8".

  • For the larger gaps, the 3E 74/10-20 will seal gaps from 3/8" to 3/4".

Since things on site are often unpredictable, you can stack tapes together to reach larger sizes: A stack of 3E 64/6-15 on top of each other will seal a 1" to 1-1/4" gap at a window head if needed.

To help with with leaving room at sills for setting blocks, we stock the same 3E 64/6-15 tape in a narrow width: 3E UA 30/6-15. The 1-1/8" width can be set forward of the setting block.  

General experience notes

The flashed rough opening should be suitable to create an air-tight joint to the Hannoband. On projects where we've seen airflow in the window gap using Hannoband, it can be traced back to three areas of potential failure:

  1. You should never be able to see daylight at the corner joints. The idea is to slightly oversize the length at corners so one side expands to fill the gap. If a piece is inadvertently cut too short, no worries, fill the gap with silicone sealant. Always plan on placing a little silicone at corners.

  2. The flashed rough opening needs to be reasonably uniform and flat. While the idea of expanding foam tape is to conform to the surfaces it contacts in compression, the foam needs some help. When using Prosoco liquid applied flashing: Start by filling gaps with Joint and Seam Filler to create a flat plane. Finish by troweling Fast Flash smooth and remove any pools. The more uniform the surface, the better able the Hanno can use compression to create an even seal.

  3. Trim at window clips by making a small slice next to the clip back to the interior but always ensuring that a minimum of one glue joint in the Hannoband is retained. While the compressed foam of Hannoband slows airflow, it's the glue joints that completely stops airflow.

It's okay to be slightly over the expansion range of the tape. It won't suddenly fail, it will just reduce it's performance slightly. You might have to add a little silicone or Prosoco Air Dam to the surface of problem areas.

It's important to place the sticky side of the 3E Hanno band against the profile of UPVC windows or other profiles with very large gaps in the profile face. 

Expanding foam tape works well to stop airflow but it's only as good as the installation allows. Start with quality rough opening flashing and take your time to join the tapes, trim around clips.  Expect to add dabs of silicone or Prosoco Air Dam at corners, over sized areas, and window clip penetrations.

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