the complete guide to using tape for insulation seams

The Complete Guide to Using Tape for Insulation Seams

There are dozens of architectural design elements to consider when building a house, but the most critical element is keeping out water and wind. That is why finding the right tape for insulation seams is vital in home and building construction. It only takes one leak to compromise the entire structure.

Why Seaming Tape is a Game Changer

There is no such thing as seamless construction. Every element that goes into constructing a residential home or commercial building joins pieces of materials together, creating seams. Sealing the seams keeps the warm air inside and the cold air outside when the temperatures drop. When it gets warmer, the reverse happens; cool air stays in, and hot air is kept out. None of that can happen without proper seals across insulation seams.

Sealing those seams also keeps moisture from getting into the building or home. Without those sealed seams, there can be a lot of issues such as damaged walls and mold to contend with. That is why choosing the right seaming tape is so important. This post will overview everything you need to know to get the best product for your situation.

How to Choose the Best Construction Tape for Vapor Barrier Seams

Energy efficiency means minimizing waste. For example, highly efficient homes ensure that  heat does not escape through insulation seams. Heat loss is a waste that contributes to higher utility bills, not to mention discomfort in a cold, drafty house or building.

Several factors go into choosing the best construction tape for vapor barrier seams. Here are some considerations to think about:

what to consider when choosing construction tape for vapor barrier seams (2)

Tape Adhesion

Every tape has a particular level of adhesion, designed for different uses. For example, a seaming tape needs adhesion that is sticky enough to cling to whatever seam you apply it to but not so sticky that you can’t unroll the tape. This level of adhesion also needs to last for a long time. Choose a tape that has been tested through all kinds of extreme temperature and moisture environments.

Flexible & Easy to Tear

A tape for vapor barrier seams needs to be flexible. It has to mold perfectly around the contours of the seam. If the tape is too thick, its flexibility wanes. This also ties into whether or not the tape is easy to tear off the tape roll. For insulating purposes, you want a tape that is flexible and easy to tear. You will be maneuvering the tape a lot, and these factors make the tape much more workable and versatile.


A quality seam tape needs to last a very long time. Ineffective tapes tend to curl after a few years. That creates a situation where the adhesion decreases, and the tape will fail. In addition, tape needs to be able to withstand adhering to its surface for a long time, while also having pressure of objects pressed up against it. This includes things like drywall, or even just storage boxes in an exposed crawl space.


Finally, the cost of a sealing tape is a significant consideration. Just because something is expensive doesn’t automatically guarantee it is high quality. When all the factors above line up for your needs, the cost should be comparable.

What Tape Do You Use for Insulation Seams?

One of the best options for insulation seam tape is aluminum foil tape. This type of tape has a rubber-based coat and strong adhesive. Aluminum foil tape adhesive works great on uneven surfaces and textures. Foil tape also is a good shield for thermal insulation.

What Tape Do You Use for Other Types of Seams?

Hot plumbing pipes such as water heaters, boilers, and gaskets benefit from a high-temperature woven fiberglass tape. Unlike standard duct tape, fiberglass tape can withstand extremely high temperatures for very long times. That makes it ideal for use on pipe insulation.

How Do You Seal a Vapor Barrier Seam

How Do You Seal a Vapor Barrier Seam?

The final step in installing a vapor barrier is to seal the seams with tape. This will create a complete moisture barrier and keep out drafts. Vapor seal tape comes in a roll with marked edges which makes for fast application.

You will need a sharp boxcutter or another type of blade for the task. Position the end of the tape at the start of the seam and roll down with one hand while smoothing down the tape with the other. The tape should be as continuous as the seam, whenever possible. This will minimize the chances of any water/vapor seeping through. If you do have to use multiple pieces, simply ensure you overlap one inch with each piece. When you reach the end of the insulation or item you are taping, slice at the roll and apply pressure to the seam.

Should You Tape Batt Insulation?

There are many things to consider when applying tape to batt insulation. We recommend taking into account the following:

  • Building Codes and Regulations for the Property

There are different requirements for building codes that a builder must follow for installation. For example, some codes call for a continuous vapor barrier for any ceiling, floor, or wall insulation. There might also be specific codes to meet concerning the type of insulation tape.

  • Factoring in the Type of Insulation

Is the insulation faced? That is the primary question to ask when deciding about a tape application. Faced insulation will have some covering, such as foil or paper. Without that “face,” it will be challenging to apply tape.

  • Accessibility of the Faced Side of the Insulation

When the facing side of insulation goes against the actual bay of the attic or crawlspace, then there is no need to tape it because you cannot reach it.

Complete Guide to Using Tape for Insulation Seams – Final Thoughts

Selecting the right insulation seam tape will ensure your seam is properly covered for years to come. When installing tape to insulate seams in commercial settings, high quality tape jobs build customer confidence and loyalty.

Over the last 50 years, Lamart has developed an impressive foil tape catalog that helps seal insulation seams with precision and durability. These tapes have been developed with the support of top-of-the-line aerospace engineers and experienced product development experts.

Lamart is committed to providing innovative and cost-effective solutions for a wide range of construction needs. It all begins with the tape for insulation seams. Contact the Lamart team to find the best tape for your insulation needs.

Craig Hirsh
Craig is a third-generation owner of Lamart Corporation with over ten years of experience developing custom-designed products to meet customer specifications and expectations.