Should You Tape Batt Insulation?

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Advice for installing batt insulation is almost as ubiquitous as batt insulation itself. Thus, you are looking for some solid instructions on whether or not to tape batt insulation. We combine industry professional knowledge and up-to-date research to answer your question thoroughly in this post.

Taping batt insulation is only considered as a means to make a continuous vapor or air barrier and is not overly common. However, whether or not you tape your batt insulation depends on several factors. These factors are as follows:

  • Local Building Code
  • Is the Insulation Faced
  • Is the Insulation also a Vapor or Air Barrier
  • Can you Reach the Faced Side of the Insulation

Keep reading the rest of this post to discuss each of the above bullet points. Once done, you will feel confident deciding whether to tape or not tape your batt insulation. Also, we answer several related questions that you should find useful.

Construction Worker Insulating Wall with Fiberglass Bat - Should You Tape Batt Insulation

Should You Tape Batt Insulation?

As with most insulation questions, the answer is not a resounding yes or no. Instead, deciding on whether it is worth taping batt insulation involves a consideration of your specific situation.

That being said, it is very common for contractors to leave batts untapped in all situations. This is not always best practice and may not significantly affect climates where vapor barriers do not play a huge role in home conditions and weatherization.

To be clear, taping batt insulation is only worthwhile if the tape will make a vapor or air barrier more continuous. Tape is rarely a suitable method of securing batts in place. Instead, if you are looking to fix batts to your framing assembly, use twine, staples, or a combination of both.

Take note, OSHA recommends hearing eye and breathing protection whenever working with fiberglass batt insulation.

Consider the following issues when choosing whether or not to tape them for your batts. The advice contained in this post applies to all types of batt insulation, including fiberglass and mineral wool.

Local Building Code

First of all, you should consider the local building code when making all of your building and remodel decisions. There are few things worse than checking off a task only to have a home inspector make you redo the entire job.

3d illustration of crane over house plan background with code sign

For taping batt insulation, it may be that you are required to have some sort of continuous vapor barrier in your walls, ceiling, or floor. There may even be a specific code on the type of tape you use and which specific batt insulation joints need to be taped.

Is the Insulation Faced?

Construction Worker Insulating Wall with Fiberglass Bat

In all cases, it is only worth taping faced batt insulation. The term "faced" means that the batt has foil, paper, or other thin continuous material on one side of the fluffy batts. Without this facing, the tape will not stick well and would not add any sort of advantage to your insulation assembly.

Is the Insulation also a Vapor or Air Barrier?

Vapor barriers are designed to stop the movement of moisture from one side to the other. They are often designed to only let that moisture move either in or out. Air barriers do the same thing but for the movement of air.

Roll of insulation wool for construction.

As discussed above, the facing of batt insulation is sometimes designed to be either both or one of these barriers. When this is the case, there will be a break in the barrier where two pieces of batt insulation butt together.

For example, if you have an 8-foot wall and two pieces of 4-foot insulation in a bay, a horizontal seam will break the facing. This seam is where you would tape the batt insulation.

The tape would then combine with the insulation facing to create a continuous solid barrier from the top to the bottom of the wall.

For the edges, where the batts meet the framing elements, there are usually ears of facing designed to either press up against the framing or stick over the edge of the framing. This means that the barrier is already continuous along the framing members.

In many situations, other elements like plastic sheeting or home wrap are the vapor or air barriers of the home. In this case, adding an additional vapor or air barrier in the form of faced insulation will create a pocket of space that is prone to collecting home damaging moisture.

Can you Reach the Faced Side of the Insulation?

Insulation facing is designed to be oriented towards a house or building's conditioned part. This means that for attics and crawlspace, the facing goes into the bays. There is no way to reach the joints to tape them in this situation.

Foam plastic Insulation of a new home on a new roof

Insulators do not bother taping these joints since it is impossible to tape the joints for attics and crawlspace. However, only skip this tapping step if you comply with all local building codes.

How do you secure batt insulation?

As mentioned above, secure batt insulation with either staples, twine, or a combination of both. If you have access to the facing of the batts - just use staples. Instead of using twine and staples for crawlspaces and unfaced batts, where you do not have access to the facing.

Click here for twine from Amazon.

In the following few sections, we cover the basic directions for securing batt insulation when you have access to the facing and when you do not have access to the facing.

Securing Batts when you have Facing Access

The facing of batts usually comes with 1/2-inch to 1-inch ears designed to stick onto the framing elements that run along both sides of the batts. When you can manipulate these strips of facing onto the framing, it is very easy to staple the batts into the wood.

Click here for staples from Amazon.

Generally, sink a staple every 6-inches to 8-inches to attach the batts to the framing. Be sure to hold the stapler firmly against the wood, or the staples may not sink into the frame.

Securing Batts when you do not have Facing Access

When you do not have facing access, either because the facing points into the bay or because the batts are unfaced, you will have to use twine to hold the batts in place.

Click here for a stapler from Amazon.

First, staple the end of the twine into the framing and then move across the bay to the other side with the twine. While pulling the twine tight, staple the twine into the other side. Continue this for the entire length of the framing bay.

Generally, each diagonal should only travel about 4-inches from one framing element to the other. There should be 8-inches or less between each point where the twine hits one continuous piece of framing.

Do I need to staple insulation?

You only need to staple insulation if it is not held in place with wall cladding or gravity. For example, if you are going to put interior cladding onto a wall, such as drywall or paneling, there is no need to add staples. This is because the panels themselves will hold the batts in place.

Further, if the batts are in an attic or other similar place, gravity will hold them in place. If you do not worry about the batts sliding or falling down, there is no reason to staple them.

What type of stapler is used for insulation?

You can either use a trigger-powered handheld stapler, an electric staple gun, or a pneumatic staple gun for insulation. For small jobs, hand-powered staplers are more than adequate. Generally, you only need staples that are 1/4-inch to 3/8-inch long.

Click here for a pneumatic stapler from Amazon.

However, if you anticipate putting a lot of insulation into place, buying a more expensive power stapler is probably worth the money.

What tape do you use for insulation batts?

The best tape is high-end seaming tape or foil-faced tape. These tape types have very high holding power and act as very effective vapor barriers.

Click here for seaming tape from Amazon.

Do not use duct tape, masking tape, or packing tape. While these household tapes may work initially, they will fail relatively quickly as the wall heats up and cools down over time.

Can you use duct tape on fiberglass insulation?

As mentioned above, it is not wise to use duct tape on fiberglass insulation. Using duct tape will not hurt anything, but in the same sense, it will not help. The duct tape's adhesive will fail over time, making the tape useless.

Additional Reading

To learn more about working with batt insulation, read these excellent HVAC Seer articles:

In Closing

In this post, we answered whether or not to tape batt insulation. We include a complete guide on making this choice, given your specific situation. To close, we answer a few related questions and cover how to secure batt insulation properly. Good luck!

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