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What Is Butyl Tape and How Do You Use It?

What Is Butyl Tape and How Do You Use It?

If you own an RV you need to know what butyl tape is, because its used in many places for sealing out water. Its not only for RV’s however as its used in many construction applications where a water-tight seal is needed. This includes roofing, plumbing, aviation, and marine construction applications.

When you’re on the road a lot with your RV, it’s important to have the right tools and materials for simple fixes along the ride. RV butyl tape is one of those essential materials. Little things can go wrong sometimes, but proper preparation makes those issues much less intrusive to the schedule. 

You are likely aware of the usability and versatility of duct tape, but do you understand the excellence of butyl tape? If not, you need to read on. Learn more about what it is and what it does, and you’ll be a better adventurer for it. 

Two Rolls of butyl tape
From windows and gutters to aircraft frames, high-quality butyl tape is a fantastic construction tool.

What Is Butyl Tape?

Silicone, rubber, and acrylic are the three main types of adhesives. Butyl tape is a pressure-sensitive rubber-based adhesive, synthetic rubber at that. It’s a solvent-based adhesive crafted in a laboratory environment rather than the natural environment of a rubber tree. 

Since rubber is sensitive to temperature changes, butyl tape’s formula makes it a little more tolerant of temperature shifts. It stays more flexible when the temperatures are cold and doesn’t get as flimsy in extremely warm temperatures. This makes it an excellent sealant/bonding agent for many practical applications. 

Butyl tape is not intended to hold things together on its own but acts more as a seal between a joint. Wall and roof fixtures should have butyl applied between them and the surface they are mounted to act as another barrier to moisture. The tape is best when squished by means of a screw. In fact, a great way to use it is behind locations where screws penetrate. This will add another layer of water protection around the screw.

RV Butyl Tape - Tips Before Application - RecPro.com

How Long Will Butyl Tape Last?

If you’re talking shelf life, we have found printed shelf life of five years. However, that doesn’t mean the tape will just be useless the day after the five-year mark. It’s just how long the manufacturer can guarantee you will get good use out of it. 

As for applications, we have helped remodel a 40-year-old RV that had lots of original butyl tape in it that was still flexible and doing its job well. There is not much that degrades it besides solvents, so as long as it doesn’t get soaked in gasoline, turpentine, or other solvents it will stay usable for a very, very long time.

One application protecting the bottom of your deck comes with a 20-year warranty on a butyl tape by the name of Trex Protect Joist and Beam Tape

What Is the Difference Between Butyl Tape and Putty Tape?

Sometimes sellers will use “butyl tape” and “putty tape” interchangeably, but there may be differences. Butyl tape is very elastic and will stretch without breaking. Putty tape will usually snap fairly easily when you stretch it. A high-quality butyl tape will not melt or freeze while a lower quality might not hold up.

One of the best ways to test butyl tape is to simply stretch a piece quickly and make sure it does not break. We personally have a few rolls on hand from Rec Pro.

Pro Tip: MOTM Readers Get 5% off at Rec Pro with Coupon Code ONTHEMOVE5.

high quality butyl tape stretch
High-quality butyl tape will stretch without breaking. Cheaper putty tapes might melt, crack or freeze and let water past.

Is Butyl Tape Better Than Caulking?

When considering whether to use butyl tape or caulking, you have to go job by job. First of all butyl tape is really designed more to act as a seal between two surfaces as its pressure is activated. This means it needs to be squished to stick. It does provide a long-lasting, dependable, waterproof seal, but there are a few shortfalls in using this material. 

The two surfaces you are attaching have to meet flush. The tape will become a dirty mess on the exposed area if there’s an open space. This could compromise the seal. 

Caulking is a great way to break through cracks and smooth a surface. Though caulking may wear out over time, it’s super affordable to rework. A tube of caulk costs nothing compared to paying for a roll of butyl tape. 

Personally, we usually use butyl tape and caulk for applications like windows and gutters where they are suited to both. In the picture below, you can see some butyl oozing out where there is a larger gap with the gutter end spout. We doubled up the butyl here, which is acceptable but also caulked the entire rail for added protection.

Butyl tape installed behind gutter
Fix your leaky RV roof and seal your RV windows with butyl tape.

Is Butyl Tape Removable?

Removing butyl tape is a job, but it’s not impossible. The tape is supposed to stick, and it does the job well. However, there are plenty of ways to get it off when you’re ready to do something else.

Start by prying up one end of the tape. Then you can use some paint thinner or adhesive remover to make the rest of the tape a little easier to pull back. You can use a putty knife to separate the tape from a given surface if you have to. 

Pro Tip: There’s more than one way to fix your RV windows. Use this guide on How to Replace Your RV Window Seals to repair your RV.

removing a window on an RV
To remove a fixture, window, and anything sealed with butyl tape you will probably need to use a putty knife to break it loose. Then dissolve the remainder with solvent and heat and scrape it off.

Pros of Using RV Butyl Tape

Aggressive Tack

One of the main perks of using it is its high initial tack. Its stickiness is aggressive, so you won’t have a problem keeping it in place. 

Bonds to Various Surfaces

It’s a valued adhesive because it is proficient at sticking to many different surfaces. You can use it on rubber roofing, glass, plastic, aluminum, galvanized metals, and even wood. 

Extremely Waterproof

It’s airtight and waterproof even in the most extreme circumstances. Rain, wind, corrosion, and not even vapors can penetrate a quality butyl tape. 

playing with butyl tape
While RV butyl tape can get expensive, it is a great tool to use for quick repairs.

Disadvantages of Using RV Butyl Tape

It’s Expensive

The cost of butyl tape could get pretty extreme if you’re doing a big job. A roll will set you back anywhere from $12 to $15, so a project requiring a lot of tape could get expensive fast. 

Prone to Oxidation and Discoloration

It’s more prone to oxidation and discoloration than acrylic adhesives. It is best used in applications where it’s completely covered.

Can Receive Damage from UV Light and Chemicals

Over time, direct exposure to sunlight, salt, or other natural chemicals can cause it to break down. The tape can become rigid and dry up, leading to cracks and instability in the seal. 

What Is RV Butyl Tape Used For?

There is a whole range of practical applications for it. In your RV, it’s good for sealing around windows, gutters, light fixtures, and anything else adhered to the walls or roof. You can also use it for small roof repairs and even to shore up some ductwork or air vents. 

Pro Tip: You may not want to pay to have the good stuff on hand, but at the very least buy duct tape for your stash. Check out these 15 Ways Duct Tape Will Save Your Camping Trip.

How to reseal RV windows the right way

Always Have RV Butyl Tape on Hand

The bottom line is that butyl tape will likely be more useful than duct tape in a “wet” situation. You certainly won’t be harmed by keeping a roll of it around for a rainy day. You may already have some lying around the garage. 

Do you have any leaky window seals to shore up? Tell us in the comments!

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Camille Whatley

Wednesday 7th of September 2022

I purchased a 2019 Thor Axis 25.6 and it recently started to leak at the kitchen cupboard right next to the front door. It's hard to find where the water is actually coming in but my thought is that it has to do with the awning and it's weight?? I duct taped where I thought was a weep hole from the antenna... but it still leaks. Then I caulked the entire length of the awning thinking if water gets in the track and a screw is somehow loose enough, water will travel to the low point. This is a guessing game and I need your suggestions on what else to do and check. I would like to be able to repair anything I can as a single female, before I have to take it in for repair, because I live in my Thor.

Thanks!!

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