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How to Replace or Install an RV Roof Vent

There's one thing all RVers have in common: they all need to breathe. This is why vents are such a necessary component of any enclosed trailer or RV—they allow the flow of fresh air, help eliminate odors, and even help protect you against gases and fumes inside the camper.Over time, your RV's roof vent can leak, break down, or simply stop moving air as well as it should. If it's time to replace your RV roof vent (or install a new vent in a new location), the good news is that this is a project you can take on yourself at home. Below, we'll go step-by-step through the process of selecting and installing or replacing a roof vent.NOTE: This guide addresses the installation of a complete roof vent assembly. If you only need to replace the cover/lid located on the outside of the RV, check out our article on that topic here.
Choosing the Right RV Roof Vent
  • Measure Roof Vent Opening
  • Measure Garnish Size
  • Select Vent Options
Installing the RV Roof Vent
  • Remove Old Garnish or Cut New Opening
  • Remove Putty and Old RV Roof Vent
  • Insert and Seal New RV Roof Vent
  • Insert New Garnish
RV Roof Vent

Choosing the Right RV Roof Vent

Before you can install a new vent, you first need to select the right unit. There are a few things to consider when purchasing a new vent or selecting a replacement.
Measure Roof Vent Opening

1. Measure Roof Vent Opening

Measure the opening for your roof vent on your camper. If you're installing a vent in a location in which there was no vent previously, you'll have to cut an opening between roof joists to install the new unit. Standard roof vent openings are 14-1/4 x 14-1/4 inches.
Pro tip: It's easiest to measure the vent opening from inside the trailer. If your trailer's vent has an interior trim piece or garnish, remove it first to expose the edges of the opening.
Measure RV Roof Garnish
The leg length of this garnish is 5" from the top of the lip to the top of the garnish.
2. Measure Garnish SizeA garnish is the trim piece that covers the vent opening on the inside of your trailer for a clean, finished look. Usually the garnish slides into a groove or channel on the vent and is attached with screws to the trailer ceiling.Garnishes come in different sizes or depths (referred to as leg length) to fit different vent models and roof thicknesses. Most vent assembly kits include a garnish, though you can purchase one separately if you need a different size.Make sure your garnish is the right length by measuring your roof's thickness from inside your trailer, then checking the garnish dimensions. If your roof is thin and you can't find a short enough garnish, you can purchase a longer one and cut it to fit with a fine tooth saw or tin snips.
Pro tip: It's best to trim your garnish indoors, especially in winter, so that the plastic remains at room temperature. Warm plastic will be easier to trim and will be less likely to crack or shatter.
Watch Now: Best RV Vent Options
3. Select Vent OptionsNow that the necessary measurements are out of the way, you can decide on color as well as any extra bells and whistles you might want, such as fans or remote control options. We'll go over some of the main options below.FansFans increase air flow and circulation and are a great choice for larger RVs and campers and for those without A/C. If your old vent has a fan, make sure the new vent has one as well, and also ensure the new vent uses the same kind of power source as your old one (most use 12V DC power, but some run on 110V AC).If you don't currently have a fan but want one, you can upgrade and make the switch by running wires to power the motor. (A good fan may even replace the need for air conditioning.)In addition, some powered vents bring even fancier options to the table. Most vents require you to crank them open by hand, but some include remotes that allow you to open/close the dome or control the fan from afar. Some also have an automatic feature, which allows the unit to sense the temperature in the camper and turn the fan on/off as needed.Metal vs Plastic Vent CoversMetal lids are the most durable type. They won't crack in a hail storm or erode in the sun. They offer a flat, low profile for additional clearance. They also block out the light when closed.Plastic lids typically have domes and are taller than flat metal covers. The dome shape allows water runoff, prevents ice damming, and is less likely to leak. Most come in white or tinted smoke colors and allow light to filter through, so you don't have to rely entirely on your interior lights. However, they are more easily damaged by the elements than metal covers are (though polycarbonate plastic covers will be more UV-resistant than polypropylene covers).

Installing the RV Roof Vent

Whether you are replacing an existing vent or installing one from scratch, the installation instructions are going to be quite similar. Check your vent assembly product description and installation instructions to see if any additional install kits or supplies are necessary. The following featured installation uses the MaxxFan Deluxe Roof Vent w/12V Fan, # MA00-06401K, on a 2018 CrossRoads Zinger travel trailer. The following should be used as guide. Make sure to read and follow all manufacturer instructions in the owner's manual included with your vent assembly kit.
Supplies Needed to Replace an Old Vent To replace an old vent, you will need:
Supplies Needed to Install a New Vent To install a vent in a new location, you will need:
Installing the MaxxFan Deluxe Roof Vent w/ 12V Fan
Remove Vent Garnish
Remove Vent Garnish
Pictured: removing garnish from vent opening

Step 1: Remove Old Garnish or Cut New Opening

If you are replacing an existing vent, remove the old trim ring/garnish piece from inside the RV.If you are installing a vent in a new location, mark the desired location for your vent (make sure to stay between roof joists). Then cut a 14-1/4" x 14-1/4" (or other size as necessary) opening through the roof and ceiling.
Scrape Putty
Remove RV Vent
Scrape off old sealant to expose screws

Step 2: Remove Putty and Old RV Roof Vent

If you are installing a vent in a new location, skip this step and move on to Step 3.On the roof, carefully peel off any old sealant around your existing vent to access the mounting screws. You can use a putty knife or other tool. Take off the vent. If you have a powered unit with wires, make sure your camper power is off and clip the wires, leaving sufficient wire length behind to make new connections. Then scrape off residual sealant to get as clean a surface as possible.
Warning: When removing old sealant with a putty knife or other tool, be careful not to scratch the roof or tear the roof membrane.
Insert trim piece and apply butyl tape
Apply butyl tape to trim ring and press into place
Make vent wiring connections
Make wiring connections
Insert new vent and fan
Insert new vent

Step 3: Insert and Seal New RV Roof Vent

Without a fan: If installing a vent without a fan, apply butyl tape or sealant to your new vent. Insert the vent into the hole (make sure it's facing the proper direction! Check your installation instructions for details) and press into place, creating a seal. Make sure all screw holes are completely covered. Screw into place with included mounting screws, then apply self-leveling sealant over the screws.With a fan: If you are installing a vent with a fan, you'll want to route your power supply and ground wires first so that you can make your connections before inserting the fan. Apply butyl tape or sealant to the trim ring and press into place, creating a seal (make sure it's facing the proper direction! Check your installation instructions for details). Make sure all holes are covered. Screw into place with included mounting screws, then apply self-leveling sealant over the screws. Make your wiring connections, then carefully mount your fan, tucking the wires inside the hole you drilled as you insert the fan. Screw into place.
Pro tip: Use the manual control knob to open the fan prior to inserting. This will make it easier to get everything in place.
Insert New Garnish

Step 4: Insert New Garnish

Attach the interior garnish piece inside the camper. Trim to fit if necessary, then screw in place. Be careful not to crack the garnish when you do so. Tuck any protruding wires out of the way (just make sure your wires don't get stuck in the fan). Test any functions of the vent, including the open/close function and the fan, if you have one.And that's it! You have a new vent. Enjoy the fresh air.
Still have questions?Email us or give us a call at 800-298-8924.
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Related ArticlesRelated ProductsWritten by: Ray P. & Amber S.Updated On: 2/18/19

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