Replace Slide Out Trim with this Tutorial (+ Photo Inspiration!)

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Looking over all the areas where water can intrude on your RV at least twice a year is a good habit for regular maintenance (and even more frequently if you use your RV a lot). Along with roof leaks, RV slide outs are one of the primary sources of water leaks on RVs. If a seal has a cut in it or is worn from time or sun exposure, you’ll want to replace it. It may seem daunting to replace slide out trim on your RV, but it doesn’t have to be!

Why Do Slides Have Seals Anyway?

Seals around the slide opening keep the elements (and bugs and critters) out.

Slide outs need room to move in & out of the body of the RV, so there is always a gap between your slide out walls and the rest of your RV. 

The two main styles of seals are wiper seals and bulb seals. The wiper seal acts like a windshield wiper, moving in and out with the slide and pushing water off the slide as it moves in, directing water away from the opening when the slide is open. The bulb seal is meant to be compressed when the slide is retracted, closing off any entry for water, wind, or critters.

Seal Basics

Seals come in many different variations. Some are two-part seals (one wiper seal and one bulb seal); some are one-piece (wiper and seal); some clip, slide, or screw onto your RV; some use self-adhesive tape.

It’s vital to know what type of seal you have to replace it properly.

Before You Start

Figure Out What Seals You Have

To determine what seal you have, extend your slide out and look at the bottom of the seal.

You can take a photo, take measurements, or cut a small piece off for reference to ensure you get the right fit for your slide.

If you decide to cut a piece off, only cut a small piece that won’t leave your RV vulnerable to the elements. Do not take your seals off until the new seals are ready to install. 

Figure Out How Much New Seal You’ll Need

Next, determine the total length of seal(s) you need.

Seal material is sold in feet, but you can measure in inches to start, then easily do the math to determine feet.

You will want to measure the outside edge of your slide, including any parts that extend downward past the actual slide side wall. The seals sit on the RV, not the slide itself, so you need to accommodate the full length of the outside wall of your slide.

You can measure the area on the RV where the seal is, but this can be a frustrating task unless you have a very stiff measuring tape.

1. Measure the side of your external slide out wall.
2. Multiply that by two for your two slide sides.
3. Then, measure the width of your external slide out wall.
4. Add this all together and determine the total feet of seal(s) you need to order.

For example, my slide sides are 83” tall, and my slide width is 125”. Totaling 291”, or 24’ and 3.” 

For the inches measurement: (83 x 2) + 125 = 291.
Then, for the inches measurement: 291 / 12 = 24’ 3.”

It’s always better to round your final number up and purchase more than you think you’ll need. So, in my example, I would order at least 26’ of my particular seal.

Some seals are sold in pre-cut lengths at a discounted rate. Check the price difference if you are close to their pre-cut lengths. For instance, if I buy 30’ instead of 26’, I could save a few dollars, and then I’ll have plenty of seal material to spare.

Don’t Forget the Bottom Seal

There may also be a seal on the bottom of your slide. This is generally a wiper seal without a bulb, and its purpose is to keep critters out. Using the same steps above (cut a small sample and measure the width of the external slide wall), determine how much and which wiper seal you’ll need.

Finally, find a source to purchase them.

• Steele Rubber Products is an excellent source for seals.
• Etrailer.com  has a few seals to choose from.
• Recpro has about a dozen options.
• Some RV dealerships may carry your particular seal, but you can find a greater range of styles online and at a better price.
• And, of course, there is always Amazon. If you buy your seals from Amazon, be sure that the store you are buying from is an Original Equipment Manufacturer (OEM). Some non-brand products may look correct but may be manufactured to a lower standard and will fail more quickly than the OEM parts.

Seal Removal and Replacement

Once you’ve received your new seals, next comes the fun part: removing the old stuff!

As you can imagine, seals are intended to stay attached to your RV pretty well, so removing them can be a bit of a chore.  Make sure you have a string of good weather days or have a way of protecting your RV from inclement weather in case you can’t finish the entire task in one day.

Tools Needed

• Ladder. Make sure it is tall enough for you to easily reach the top of your RV.
• Gloves to protect your hands from potential scrapes or cuts.
• Screwdriver. Usually, a Phillips style is all you’ll need.
• Adhesive Remover (GoofOff works well) and a good supply of rags.

• Plastic Scraper/Tuck Tool.  The plastic will not damage the surface of your RV like a metal part might.

Safety Notes

Safety is always a concern when working on the outside of RVs. Make sure your ladder is in good shape, and use a spot person if needed. 

You shouldn’t need to get on the roof to access the seals, but if you do, protect the surface with cardboard or a moving blanket.

The “How To” Steps

1. Position the Slide

Extend the slide 6-10” to give yourself access to the seal(s). You don’t need to extend the slide fully; you’ll want it to be close to the RV once you get to the top edge for easier access.

If you have a slide topper, you’ll need to remove it to get full access to the seal at the top of your slide.

2. Peel the Seal Off

Start at the bottom of one side & start peeling the seal off. Some seals are secured with a screw to prevent them from sliding, so look for one if your seal isn’t moving. You may have to peel up a portion of the seal to locate it. Depending on the type of application (adhesive, clips, or track), removal will be a little different.

Continue up and over the slide, removing the old seal as you go.

3. Clean the Area

Remove any debris that may interfere with the new seals.

If your seals were attached with adhesive, clean off any adhesive that is left over. This can be a time-consuming part of the prep work, but do not skip this step. You want a clean surface to attach your new seal to.

While doing this work, it’s a good time to clean off the top of your slide and note if the top needs to be resealed or re-caulked. It’s also an excellent time to look over your roof (if your ladder is tall enough to see it) and see if it needs any work, such as new sealant around vents/AC/skylights.

4. Apply the New Seal

Again, the attachment method will depend on the type of seal you are replacing. The wiper seal should make solid contact with slide out sides and roof, bending enough to create a good seal. 

The amount of contact the wiper makes may be different on the right and left sides of the slide, as your slide may not be perfectly centered in its opening. This is not necessarily a problem as long as the slide works. The most important thing is that the seal is snug to the slide.

5. Apply Sealant

Once your new seal is on, you’ll want to make sure all potential moisture access points are well covered with sealant.

What to Do in the Corners

During this process, if your seal is one long piece, you’ll notice that the wiper isn’t sitting flat in the corners.

Since the seal is one piece, it can’t make that 90º turn cleanly, and you’ll have to cut it to make it work properly. Take the wiper seal that extends from the top of the slide opening and fold it over the part that extends from the side.

At the fold where the wiper bends, cut through the wiper only. (Don’t cut the bulb part of the seal.)

You can then fold the flap from the top over the flap from the side. This will allow water to flow down over the side seal and not behind the side seal.

Glue the top wiper seal over the side wiper seal using a gel super glue product. This will keep the top seal from slipping behind the side seal, which would give moisture an opening to your RV.

Dealing with Corner Gapping

There may be a gap in the corner as well. Use a good sealant such as Geocel ProFlex in the top corner to make sure no rain can get into your camper from behind the seal.

Dealing with Corner Edges

If your seal is the type you cut for each edge (side, top, side), you may need to use Geocel ProFlex along the edges, as well as any other areas where moisture can potentially enter your RV.

These seals will have a screw or two securing the seal to the RV. It’s recommended that you put a dab of sealant on those to prevent moisture from entering and corroding the screw. If the old screws are corroded, replace them with similar-length screws.

6. Do the Same for the Bottom Wiper Seal

Now crawl underneath the slide and remove the bottom wiper seal. It’s usually attached with screws and perhaps a metal track to keep it solidly attached to the RV.

Cut your new seal to length and reattach using the screws and/or track you just took off.

Again, replace the screws if they are corroded, and add a dab of sealant on each screw.

7. Test it all Out

Run the slide in to ensure you have at least 50% compression of the bulb seal. If you don’t have 50%, you may have to adjust your slide itself.

Confirm that your seals maintain contact with the slide’s sides and top. And voila! You now have new slide seals.

Caring For Your New Seals

Now That You’ve Got Fresh Seals on Your Slide, How Do You Maintain Them?

Many manufacturers recommend soap and water to keep them clean. Make this part of your end-of-trip storage practice to keep on top of maintenance. A rubber conditioner should be used regularly, too.

The frequency will depend on how often you use your RV, but a good practice is cleaning and conditioning the slides at least twice a year.  Add this task to your winterizing and de-winterizing list!

There are Many Different Seal Lubricants on the Market, So Which One Should You Choose?

Make sure it’s a dry lubricant. This means that it doesn’t contain any oils that may corrode your seals. Dry silicone is a popular option. If the label says it’s PTFE, that just means it’s Teflon. As long as it’s dry, you’re good to go!