RV Roof A/C Shroud and Gasket Checks for Desert Owners

Your rooftop air conditioner is the heaviest thing on your RV roof, and in Las Vegas it works harder than almost anywhere else. It also sits over the biggest hole in the roof. Two parts keep that spot dry and protected: the plastic shroud on top and the foam gasket underneath. Here is how desert sun and road miles wear them down, what you can check yourself, and when it is time for a shop inspection.

How the A/C sits on your roof

Most rooftop units mount over a square opening cut through the roof and ceiling. Dometic's installation manual, for example, calls for a 14.3 in × 14.3 in opening. The unit rests on a thick foam roof gasket that seals that opening, and bolts from inside the coach pull the unit down onto the gasket. The shroud is the plastic cover that protects the unit's internals from sun, rain, and debris.

That design means three things matter for keeping water out:

• The gasket has to stay compressed evenly all the way around.
• The mounting bolts have to stay at the right tension. Dometic warns that over-tightening can damage parts, and that insufficient torque "may compromise the roof seal and cause leaks."
• The roof around the unit has to stay flat and sound. Dometic also warns never to create a low spot on the roof, because pooled water can leak inside.

What desert sun does to shrouds and gaskets

Hours of direct sun every day are hard on plastic and foam. Over time you may see:

• Chalky, faded, or brittle shrouds. Sun-baked plastic can crack at the corners, around the screw holes, or where branches and storage covers rub.
• Loose or missing shroud screws. Road vibration works screws loose, and a loose shroud can rattle, crack, or catch the wind.
• A flattened or crumbling gasket. Foam can lose its spring with age and heat, so it no longer seals tightly against the roof.
• Dried, cracked sealant on the roof near the unit's base and on nearby seams and fasteners.
• Soft roof around the unit. The weight of the A/C and people standing near it to clean it can flex the roof and stress seams nearby.

Signs worth checking

• Water stains or bubbling on the ceiling around the A/C's interior grille.
• Drips from the grille after rain or a car wash with the A/C off. (Drips only while it runs on a dry day point more toward condensation.)
• New rattles or a "loose" sound from the roof when you drive.
• Visible cracks or holes in the shroud from a ladder.
• A roof that looks dished or dips near the unit, or water that sits there after rain.

If water is already coming in, our post on what to do if your RV roof leaks during a Las Vegas rain covers the first steps.

A safe check from a ladder

You can spot most shroud and gasket problems without walking on the roof:

1. Look at the shroud for cracks, chalky spots, missing pieces, or gaps at the base.
2. Check the shroud screws you can see. Note any that are missing or loose, but do not overtighten plastic.
3. Look at the gap between the unit and the roof. It should look even all the way around, with no torn or squeezed-out gasket.
4. Scan the roof around the unit for cracked sealant, lifted seams, or a low spot.
5. From inside, look at the ceiling around the grille for stains or sagging.
6. Take photos of anything that looks off, so the shop can see what you saw.

Stay off the roof in wind, rain, or midday heat, and leave mounting bolts to a qualified tech. Getting them wrong in either direction can cause the leak you are trying to prevent.

Habits that help

• Replace a cracked shroud instead of taping it. Tape breaks down quickly in the sun.
• Keep debris off the unit. Leaves and dirt trap moisture around the base.
• Avoid standing right next to the unit unless the roof is rated for foot traffic.
• Do not smear caulk over the gasket. It can hide a failing seal and make the unit harder to service.

Storing your coach between trips? Our guide to RV storage roof care, covered vs uncovered covers more ways to cut sun exposure.

How Sky Sealed handles the roof around your A/C

At our Las Vegas shop, an inspection looks at the full roof: the membrane, seams, decking, and every penetration, including the A/C opening, vents, and skylights. Prep includes cleaning, drying, and repairing soft spots or failed flashings before any coating goes on. A failing gasket or cracked shroud should be dealt with at this stage, not coated over.

Our fabric-reinforced silicone system embeds fabric at seams, vents, and penetrations, the high-stress spots where roofs move the most. Every job starts with a written quote based on your coach's length, condition, and the system chosen, and qualifying full systems come with a 20-year workmanship warranty, with terms in writing.

Want to know what a visit covers? Read what a shop RV roof inspection includes.

Frequently asked questions

What does the gasket under an RV air conditioner do?

It seals the roof opening under the unit. The mounting bolts pull the A/C down onto the foam gasket so water cannot get past it into the opening.

Why does my RV leak around the A/C only after rain?

If drips show up after rain with the A/C off, the gasket, the sealant around the base, or the roof nearby may be letting water in. Drips only while the A/C runs on a dry day point more toward condensation.

Should I tighten my A/C mounting bolts myself?

It is safer to leave that to a qualified tech. Dometic warns that over-tightening can damage parts and that too little torque can compromise the roof seal.

Does Sky Sealed come to my house or storage lot?

No. Sky Sealed works only in our shop at 4416 Alderbaren Ave in Las Vegas. There is no mobile crew.