New Product-Siga’s Rissan Window Flashing System

If you’ve been reading my blog for a while, you know I’m a big fan of Siga’s water and air sealing products, especially their tapes.  Recently they came out with two products that substantially reduce the time it takes to flash window rough openings. 

Siga’s recommendations for window water and air sealing used to involve several products and a lot of complicated tape cuts and layers to meet their requirements per their window flashing guide.  The following photos are from my recent Barndominium project.

The two window rough openings in the photo above took nearly two hours to achieve Siga’s recommended water and air sealing requirements.  The updated process using the Rissan 430 would have taken less than half that time.

With the new system, all I need are the corners and the Rissan straight tape.  Rissan 430 Grey is a vapor closed exterior straight tape designed with window water and air flashing for rough openings in mind.  The split-back tape is available in both 6 and 9-inch versions, the 6-inch would be ideal for 2×4 wall assemblies, and the 9-inch is what I would use on 2×6 walls or when a wood window buck is part of the window rough framing assembly.  The straight tape is installed on the bottom sill before the corner tapes are placed.  The tape should be cut long enough so that it fills the entire bottom sill without extending up the vertical window framing.  The tape is applied by peal half the backer, position and use hand pressure to stick in place, peal the other half of the backer and fold around the 90° corner of the opening.  Finish wetting* the tape by using a squeegee or roller.

Rissan 430 Grey Corner is a pre-formed inside corner tape.  It fits perfectly in the inside corner of a window rough opening.  The corner also features a split backing that allows for easy placement without having the corner adhesive stick to your fingers during placement.  I found it easier to stick the inside corner first, then remove the outside face backer, adhering to the wall sheeting or window buck assembly.  Wet* the tape by pressing firmly using Siga’s squeegee or a roller.  I found the tape installs easier than other sill protection systems, there was no bunching of the tape in the corner and no “fish mouths” to direct water behind the tape, which can be common with other systems.


Finish the taping by installing tape between the wall sheeting and window rough opening framing along the sides and top to assure a good air seal at those connection points.

Nether of the 430 tapes need a primer, even when adhering to OSB.  The low limit application temperature is 14°F.  The perm rating of the tape is .046, below the level of polyethylene sheeting, commonly used as a vapor barrier in cold climates.

I prefer to install products as a system, for instance, if I’m using Huber’s Zip Sheeting, I prefer to use their tapes and other product accessories to complete the installation.  This might be an exception; I’m so impressed with Siga’s corner and straight tapes for window water and air sealing, it might become my new assembly no matter what WRB manufacturer is used.

Here is a link to Siga’s installation instructions for the new Rissan 430 tape.

A second link to Siga’s technical data sheet for the Rissan 430 tape.

*”wetting the tape” is the process of having the tape’s adhesive fully adhere to the substrates the tape is being applied to.  Tapes need pressure along their entire surface to correctly and completely adhere to the surface.  Simple hand pressure is usually not enough, a J-roller or squeegee is typically required. 

6 Replies to “New Product-Siga’s Rissan Window Flashing System”

  1. In Massachusetts, the exterior studs must be 2″ x 6″ and I notice you are showing 2″ x 4″ construction. Does the larger wall thickness affect the sizes of this new tape product?

    1. Hi Ron,

      The straight tape comes both in 6-inch widths, which is what is on the wall mock-up, and in 9-inch width that works better with the 2 x 6 framing. In Minnesota, unless there is a structural constraint, we can frame in 2 x 4 as long as we still achieve the minimum R-value for our climate zone, which is R-21. We would need to add exterior insulation in that case.


  2. Very nice detailing Randy. SIGA makes some seriously sticky tapes. I used Rissan and Wigluv on my own house. I see Majrex in the background too, looks like an all-around quality build. Wish more folks would build this way. Any blower door scores?

    1. Hi Brian,
      The project that required the tape origami was the barndominium build, that 10,000 square foot project ended up at .38 ACH50 for the whole structure. Tricky building to blower door test given its volume and air tightness. When I turned the blower door fan off after completing the negative pressure test, we had an in-rush of air back through the blower door, this lasted for 15 seconds or so.

      I have yet to use the new Siga preformed window corners on a project, the photo is a mock-up I built this past winter. Hopefully I’ll have the opportunity soon.

  3. Interested in using your Rissan 430 light gray color tape on my old camper. Floors rotted out due to bottom trim failure. Will this stick well to fiber glass composite wall and down around the vinyl mesh underbelly fabric? I then cover the tape with white flex tape straight down the side to a folded drip edge. This worked well on a a section that I fixed several years ago, but the window tape had Red logos and you see the Red through the Flex tape. Where can I buy your tape?

    1. Hi Ben,

      I have yet to see Siga’s Rissan Grey tape in the wild. I got a sample from Siga at a trade show. As far as sticking to fiberglass and fabric, you would probably need to test to see how well any tape bonds to those two very different materials. If it were me, I would clean the surfaces and apply the tape, make sure you get good pressure across the tape’s surface. After 24-48 hours, the tape will be at full bond. Try pulling it off, if it can be easily removed from either surface, you’ll have to find another. You might want to try Siga’s Fentrim 430 grey tape. It’s expensive but one of the best for bonding to several different construction materials.


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