This post originally appeared in the August/September 2022 issue of Fine Homebuilding Magazine. Choosing the Right Construction Tape for the Job – Fine Homebuilding
Walk through any modern construction project and you’re bound to see construction tape somewhere on the site. Whether it’s taping the seams of a mechanically attached water resistive barrier (WRB), flashing a window or door opening, or making sure an air barrier is continuous, tapes have become a key part of many assemblies. Mostly, we use tapes for two purposes, to keep something in, like the air we pay to condition, or keep something out, like water. It’s important to use the right product for the right application.
My first experience using a construction tape was taping Tyvek seams on the exterior of a home. That type of tape, which is still in use today, looks similar to a traditional packaging tape that would be used to seal a cardboard box. Back in those days, we would seal the Tyvek seams and use that same tape to seal the window flanges to the Tyvek. We learned quickly not to use that tape in that application.
A more recent incident led me to perform a backyard tape test. We were having issues with a high-performance tape bonding correctly in cold temperatures. The tape was applied at the bottom end of the manufacturer’s recommended application temperature, which was 14°F.
To determine if it was the tape or something we were doing wrong, I decided to try several different tapes applied on different surfaces during cold weather. Some worked better than others, as it turned out, the tape we were using was one of the best overall performers. (You can read about that tape test at Testing Construction Tapes, Part 1 – GreenBuildingAdvisor)
Pressure sensitive adhesives or construction tapes are used in many applications. Keeping water out of our assemblies is one of the more common purposes. Taping the seams of a mechanically attached WRB, like Tyvek, or factory applied WRB such as Zip Sheathing can be an effective water shedding assembly, as long as the tape is applied correctly. (See installation methods.) We can also use tapes to protect window and door sill rough openings from water damage, water seal planned penetrations through wall assemblies, such as a dryer or bath vent, or seal foundation to wall or wall to roof connections. Tapes used for water management will often also keep air from moving through the connection.
Personally, I’ve always been a fan of using one manufacturer’s products as one assembly. For example, when using Tyvek house wraps, I prefer to use Tyvek’s family of tapes, Siga’s air and vapor membranes combined with Siga’s tapes, etc. Each have been tested as a system and I feel they will perform the way intended, again, as long as they are installed per the manufacturer’s instructions.
Tapes are designed to adhere to many different surfaces, wood; both engineered and boards, insulation materials such as XPS, EPS and Polyiso, plastics, PVC’s and fiberglass, such as the materials used for window nailing flanges, metal, glass and concrete. Depending on the surface type and manufacturer of tape, the surface being taped to may require a primer. Some manufacturers may require OSB to be primed before applying tape, others will require a primer to be used on concrete. Check with the manufacturer’s recommendations for specific requirements.
Tape adhesion, or how well a tape will stick to a surface is based on several factors. How smooth, rough or porous a surface is one of the bigger factors. The viscosity of the glue and its ability to make full contact with the surface also affects adhesion. This viscosity may change depending on ambient temperatures. Some tapes will “creep” or move on a surface when temperatures are too high, other tapes may not adhere at all in low temperatures. Another factor will be how clean or dry the surface to be taped is, dust and debris should be removed. Some tapes will work on damp surfaces while others require the surface to be completely dry.
Some tape manufacturers have a list of materials their tapes are not compatible with. For instance, Siga recommends not applying their Wigluv tape to GE’s Silicone II Window and Door, Henry’s 212 All Purpose Crystal Clear or Tremco’s Spectrem 2 products. Check with the tape manufacturer for limitations.
Types of Tapes
There are three main types of tapes used in construction today, acrylics, butyl and rubberized asphalt, sometimes called bituminous or modified bitumen. There are advantages and disadvantages to them all. The most popular, and usually the most expensive are the acrylic tapes. These types of tapes can be very elastic; Zip System Stretch Tape is an acrylic. Many can be applied in lower temperatures, and they bond well with most surfaces. In some instances, it may take a few hours or up to a few days for the adhesive to fully cure to the taped surface.
Butyl is the second type of common construction tape. These tapes tend to be slightly cheaper than the acrylics. Butyls are UV and thermally stable. They can be applied during lower temperatures, but in my experience with the cold weather tape test, the acrylics outperform most in cold weather. Tyvek’s StraightFlash, used in window and door flashing, is a Butyl tape.
The last type of tape is the rubberized asphalt, think ice and water shield. They work well with irregular surfaces but do not adhere in cold weather. Some tapes can “creep” or move when exposed to high heat. Rubberized asphalt tapes tend to be the cheapest option. Grace Vycor Plus is a rubberized asphalt tape.
A factor in a tape’s performance is the material the adhesive is applied to. This “support surface” or “backing” can vary, for instance, a UV resistant facing can be exposed to sunlight and will often be used in an open cladding system. Others will have a reinforcing band running through the tape to improve durability and strength or use a backing that can be greatly deformed, such as Zip’s Stretch Tape. You will want to do some research to determine which tape is best for an application.
1. Release liner-A removable non-adhesive layer that prevents the tape from sticking where you don’t want it to. Can be split to aid in layering and positioning.
2. Adhesive-Quality construction tape has two layers of acrylic, butyl, or rubberized asphalt adhesive. Tape must be rolled for the best bond.
3. Reinforcing layer-A fibrous layer that gives the tape tear resistance and stiffness for durability and easier installation.
4. Primer-Helps the adhesive stick to the backing.
5. Backing-The surface that supports the adhesive and other tape layers.
Construction tapes come with several different options. The width of the roll is one, another is the release liner. The release liner, or lack of one, can slow or speed installation. Certain tapes, such as Zip’s Flashing Tape (can be ordered either with or without a release liner) or Tyvek’s Seam Tape do not have a paper liner. The tape’s adhesive is in direct contact with the tape’s backing. Other tapes have a paper or plastic liner that must be peeled off before the tape will adhere. Some of the tapes can also have a spit liner, meaning that a portion of the liner can be removed at a time, this simplifies taping inside or outside corners. The split liner also makes it easier when working with very wide tapes such as the 12-inch-wide 3M 8067 tape used in the photograph, that tape has a 2”-10” split liner. A newer release backing has been produced by Rothoblaas, a tape called Smart Band has a plastic release liner that can be split anywhere on the liner. Simply create a nick and the release liner can be pealed apart, convenient if you need a 25/75 or any other ratio liner split. Some tape manufacturers have designed their liners to be recyclable.
There is a reason tapes are called pressure sensitive adhesives; they require pressure to active the adhesive and achieve a full bond to the taping surface. This pressure needs to be produced along the entire length of the tape. Many tapes are required to be rolled using a J-roller, often this is printed right on the face of the tape. Other manufacturers want the tape to be smoothed out with constant pressure using a squeegee or similar tool.
Some WRB systems, such as Zip System, will not have a true “shingle lap” of the water resistive layer to keep water on the surface of the WRB material. The tape becomes the critical water shedding component. In these applications, it’s important the tape is installed flat and without “fish mouths” or wrinkles that can become a funnel for water to enter an assembly. Care must be taken during installation and the manufacturer’s instructions on “wetting” or rolling the tape must be followed.
Even though we are applying a sticky product to a surface to seal something in or out, it’s best practice to still shingle lap the tape when possible. I start at the bottom of the area needing tape and working my way up the assembly. For instance, on a wall, I might start taping at the wall to foundation connection, then tape any vertical seams to the first horizontal seam, lapping over the previously installed foundation to wall tape, and so on until I work my way to the top of the wall.
There are a couple different methods I use when applying tape from a roll. If there is no release liner, I unroll short lengths of the tape, smoothing with my hand as I move along. When I get to the end of the area requiring tape, I cut the tape and then go back over the area just taped using a J-roller. If there is a release paper on the tape, I either use a similar method, pealing the release paper and then applying the tape in short sections from the full roll, or I cut the tape to a specific length, and then peal short lengths of the release paper at a time as I move along the area needing to be taped. Which method I use depends on the length of the area requiring tape, under 10 feet or so, I’ll cut to length. Longer lengths, such as when taping the entire length of a long wall, I will leave the tape on the roll, that way there are less seams in the tape.
Inside and outside corner taping can be challenging. Having a tape with a split liner can simplify the process. I cut the tape to the needed length, then remove a small section of the split liner from one side of the tape. I start applying the tape to one side from the top of the corner, working my way down, pealing and applying short sections of the tape as I move along. Once one side is completely adhered, I repeat with the second half. Wider tapes can simplify the inside/outside install. Using a squeegee or the butt of a speed square can help in placing the tape tightly to an inside corner. Be sure the tape is tight in the corner, any radius in the tape will complicate any finishing work that’s needed, often resulting in someone cutting the tape and ruining the tape’s purpose.
Construction tapes continue to improve and evolve. They’ve simplified how we address air sealing details and have helped to keep our assemblies dry. Understanding where, when, why and how to use a specific tape requires some research. Most manufacturers have instruction details on their websites, and many have trained representatives to help answer questions. Tapes will usually be covered by a finish, making it difficult to access if an assembly is not constructed correctly. Choose the right product for the right application. A wise man once said to tape and try and caulk and care, how true!