RV Rooftop A/C Gasket Size Guide: 14×14 vs 14×16 & Mounting Kits

Replacing a compressed roof gasket is not the same as replacing the entire rooftop air conditioner. The seal must match the specific A/C base and its mounting instructions, even when the RV has a common 14 × 14-inch roof opening. Compare the original gasket shape, required size, leveling components and mounting bolts before removing the rooftop unit.

14 × 14 roof opening or 14 × 16 A/C gasket?

Roof openingThis is the hole through the roof into the ceiling assembly, often nominally 14 × 14 inches. It is not always the dimension of the foam gasket mounted beneath the rooftop unit.
Gasket footprintVentmate 65526 is listed as a 14 × 14-inch gasket, while 65527 is a 14 × 16-inch seal configuration for specified Coleman-Mach models. Select the gasket from the actual A/C model, not the ceiling cutout alone.
Mounting hardwareBolts draw the unit down to the specified gasket compression. Roof thickness and model determine whether 8- or 9-inch mounting bolts are appropriate; a gasket kit does not automatically include them.

Roof A/C gasket and mounting parts by exact MPN

The chart separates self-adhesive picture-frame seals, multi-strip replacement seals, model-specific Dometic gaskets and separate bolts. The listed kit contents are not interchangeable merely because the parts share a similar opening size.

MPN Seal / mounting part Manufacturer size reference Included Selection
ACGR-1 Dicor Seal-Tite — Universal-size rooftop A/C gasket kit Manufacturer-described universal replacement gasket Self-adhesive gasket, adhesive leveling blocks and compression guides Compatible rooftop A/C assemblies only after the unit's original seal, roof opening and compression instructions are checked.
3310718.006 Dometic — Rooftop A/C installation gasket 14 × 14 in nominal opening Roof sealing gasket; separate leveling pad not catalogued as included Selected Dometic rooftop A/C bases; model-specific parts list required.
4450037541 Dometic — FreshJet 5 roof gasket kit Approx. 14 × 14 in inside / 17 × 17 in outside Model-specific roof gasket; not the complete mount or fastener set FreshJet 5 model family; verify the complete FJX model code before ordering.
65526 Ventmate — Coleman-Mach square A/C gasket 14 × 14 in gasket configuration Pre-sealed gasket; separate leveling pad not listed Coleman-Mach installations specifying this exact seal size.
65527 Ventmate — Coleman-Mach rectangular A/C gasket 14 × 16 in gasket configuration Pre-sealed gasket; separate leveling pad not listed Coleman-Mach installations calling for a 14 × 16 in gasket, regardless of how the roof opening is described.
25071 Camco — Roof A/C picture-frame gasket and leveling kit 14 × 14 in picture-frame gasket Self-adhesive gasket plus two 1-7/16 × 18 in leveling pads of different thicknesses Compatible roof units requiring a 14 × 14 in gasket and leveling support. Camco says not to apply liquid caulk or silicone with this compression gasket.
A10-1414 Valterra — Four-strip self-adhesive roof A/C seal kit Approx. 14 × 14 in assembled inside / 16 × 16 in outside Four adhesive-backed strips forming the sealing square Compatible roof A/C bases; four-piece strip construction differs from a preformed picture-frame gasket.
8333-3211 Coleman-Mach — 9-inch A/C mounting bolts 9 in length; four bolts Bolt set only; no gasket or leveling pad Match the rooftop unit and roof thickness to the exact required bolt length; never select bolts by gasket size alone.
9108553390 Dometic — 8-inch rooftop A/C mounting-bolt kit Four 1/4-20 × 8 in bolts per supplier specification Mounting bolts only; no roof gasket Selected Dometic rooftops requiring this length and thread; verify manual and original hardware.
Check the original gasket specification: A 14 × 16-inch seal may surround an A/C with a nominal 14 × 14 roof opening. Conversely, a FreshJet 5 unit may require its model-specific Dometic gasket even when the roof hole is a common size. Avoid choosing a “universal” gasket without verifying the A/C maker’s permitted seal and compression requirements.

Before lifting or reinstalling the rooftop air conditioner

  1. Identify the A/C model and service number: Look at the rooftop unit label and its installation manual, not just the ceiling grille or thermostat.
  2. Compare the old seal: Record the gasket shape and dimensions, whether it is a one-piece frame or strip assembly, and where leveling pads are positioned.
  3. Inspect the mounting surface: Check roof condition and any deformation or leak damage. Do not compress the gasket to compensate for an unstable roof.
  4. Use the correct compression method: Follow the manufacturer's sequence and gasket-compression or bolt-torque instructions. Overtightening may cause leakage or roof damage.
  5. Do not improvise sealant: Camco's instructions for the 25071 compression gasket prohibit liquid sealant, silicone and caulking used with that seal. Follow the exact replacement gasket's manual rather than using a generic caulk method.
  6. Manage electrical and lifting hazards: Disconnect required shore/generator/battery supplies and have qualified help lifting and servicing the heavy roof A/C.

Common gasket selection questions

Does Ventmate 65527 automatically fit every 14 × 14-inch rooftop hole? No. Its 14 × 16-inch dimension refers to the specified gasket configuration, not universal compatibility with any unit above a square roof cutout.

What is included with Dicor ACGR-1? Dicor identifies a self-adhesive roof A/C gasket, adhesive-backed leveling blocks and installation compression guides.

Can I use 9-inch Coleman-Mach bolts in place of Dometic's 8-inch bolts? The two bolt kits have different stated lengths and applications. Select only the specific bolt length, thread and quantity required by the original installation instructions.

Shop rooftop A/C gaskets and mounting components

Open the exact part number for product photos and current availability. The first group contains gasket kits; the second group consists of mounting hardware only.

Rooftop air-conditioner sealing gaskets

Separate roof A/C mounting bolts

Related rooftop A/C model diagrams

Before buying installation parts, locate the original model in our Dometic rooftop A/C model directory or consult a relevant Coleman-Mach 15 parts reference. For a newer installation, see the Furrion Chill HE R32 roof-mounting guide. Different generations may require different seals.

Manufacturer source: Dicor Seal-Tite ACGR-1 specification (catalogue PDF). For all other gaskets and bolt kits, use the exact rooftop unit's current manufacturer installation instructions.

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