Geocel 2300 vs. 2320 vs. RP-400: Which Roof Sealant Fits Your Job?
by ShopGeocel
Choosing a roof sealant starts with the job, not just the cartridge. Geocel 2300®, 2320®, and RP-400® serve different repair needs. Here is a quick guide to help narrow your choice.
At a glance: 2300 vs. 2320 vs. RP-400
| Geocel 2300® | Geocel 2320® | Geocel RP-400® | |
|---|---|---|---|
| Type | Solvent-based tripolymer sealant | Semi-self-leveling tripolymer sealant | Asphalt-based roof cement (asbestos-free) |
| Best for | General roof sealing, flashing, trim, gutters, solar mounts | Narrow seams, lap joints, gutter joints and end caps | Roof leak repair on wet or dry surfaces |
| Wet surfaces | Bonds to damp, oily, or frozen surfaces | Adheres to damp or oily surfaces | Applies wet, dry, or even underwater |
| Consistency | Non-stringing gun-grade | Flows and levels into the joint | Soft, pliable cement |
| Paintable | Yes | Yes | No — do not paint or thin |
| Colors | Clear, White, Gray, Black, Brown, Bronze | Clear, White, Aluminum Gray | Black |
| Size | 10.3 oz cartridge | 10.3 fl. oz cartridge | 10 oz cartridge |
| Buy as | Single cartridge or case of 24 | Single cartridge or case of 24 | Single cartridge or case of 24 |
| Part numbers | GC66100 (Clear), GC66101X (White), GC66102X (Gray), GC66103X (Black), GC66104X (Brown), GC66105X (Bronze) | GC67100X (Clear), GC67101X (White), GC67102X (Aluminum Gray) | GC01103 (Black) |
| Watch out for | — | Maximum joint size 1/4" × 1/4"; not available in California | Not for single-ply membranes (EPDM, PVC) |
Geocel 2300®: General roof sealing, flashing, and trim
Choose 2300 when you need a flexible, paintable tripolymer sealant for roof sealing, flashing, trim, or gutters. It bonds to damp, oily, and even frozen surfaces, resists UV and mildew, and applies without stringing. It exceeds ASTM C-920 requirements and stays permanently flexible, so it moves with the roof instead of cracking out.
Shop Geocel 2300® Roof Tripolymer Sealant
Geocel 2320®: Narrow seams and gutter runs
Choose 2320 when the job calls for a semi-self-leveling tripolymer sealant for narrow seams, lap joints, or gutter runs. This is the choice for gutter professionals: it flows into the joint and levels itself for a clean, watertight finish. It works on aluminum, galvanized, and vinyl-clad gutters, as well as flashing, vents, metal awnings, and thresholds, and it is compatible with asphalt shingles. Keep joints to 1/4" × 1/4" or smaller.
Shop Geocel 2320® Tripolymer Gutter and Narrow Seam Sealant
Geocel RP-400®: Black asphalt-based roof repair cement
Choose RP-400 when the repair calls for a black, asphalt-based roof cement for wet or dry surfaces — it can even be applied underwater, which makes it a go-to for emergency leak repairs. It seals quickly, remains soft and pliable, and bonds to asphalt, steel, brick, wood, aluminum, and other common building substrates. It is a different product category from the paintable tripolymer sealants above.
Important: Do not paint or thin RP-400. It is not for EPDM or PVC single-ply membranes.
Shop Geocel RP-400® Wet-Dry Surface Roof Cement
Quick picks by job
- Sealing flashing, trim, or roof penetrations that will be painted: 2300
- Gutter seams, end caps, and narrow lap joints: 2320
- Stopping an active leak in the rain or on a wet roof: RP-400
- Color-matching a finished surface: 2300 (six colors) or 2320 (three colors)
- EPDM or PVC single-ply roofs: not RP-400 — check the manufacturer's data sheet for a compatible product
Frequently asked questions
Can I paint over these sealants?
2300 and 2320 are paintable. RP-400 should not be painted or thinned.
Which one can I use on a wet roof?
All three bond to damp surfaces, but RP-400 is the one designed for wet application — it can be applied to wet or dry surfaces and even underwater.
What is the difference between 2300 and 2320?
Both are tripolymer sealants. 2300 is a non-stringing, gun-grade sealant for general roof sealing, flashing, and trim. 2320 is semi-self-leveling, so it flows into narrow seams and gutter joints and levels out on its own.
Do I have to buy a full case?
No. All three are sold as single cartridges or by the case of 24.
Can I order 2320 in California?
No. Geocel 2320 is not available in California.
Before you order
Check the roof material, joint design, finish requirements, and current manufacturer application instructions. These products are not interchangeable for every roof system. Match the product to the specific substrate and repair, and check the selected color and pack size for availability.