Dicor RP-USP-P Ultra Sealant Primer 16 Oz - Prep for TPO and EPDM

In this review the Dicor RP-USP-P Ultra Sealant Primer is examined as the preparatory step for sealing TPO and EPDM membranes. It is aimed at RV owners, roof repair DIYers, and technicians who need a primer that promotes reliable adhesion of Dicor's ultra sealant to plastic appliances and roofing materials. The single biggest reason to buy is its role as Part 1 of the ultra sealant system: using this primer is what enables the sealant to bond and remain effective on horizontal and even some vertical surfaces.

Key Features

• Part of a two-step system: Designed as Part 1 to prepare TPO and EPDM so the ultra sealant will adhere properly for a long-lasting seal.
• Surface preparation: Must be used on plastic appliances and roofing membranes to remove barriers to bonding and improve sealant performance.
• High-grade materials: Manufactured with premium materials to provide consistent priming and reduce the chance of adhesion failure when followed by the sealant.
• Clear formula: The clear 16 oz formulation allows precise application without altering the appearance of the roofing or appliances.
• Everyday usability: Straightforward to apply for routine maintenance or seasonal roof checks, making it practical for RV and rooftop maintenance tasks.

Who It's For

The primer is best for RV owners, roof maintenance professionals, and DIYers working with TPO and EPDM membranes who plan to use Dicor ultra sealant. Anyone sealing vents, plastic appliances, or membrane seams will benefit because the primer promotes the specific bonding that the sealant requires.

Those who should look elsewhere include users who are not using Dicor ultra sealant or who need a multi-surface construction adhesive rather than a dedicated primer. If you need an all-purpose primer for varied substrates beyond TPO, EPDM, and plastics, a different product might be more suitable.

Pros & Cons

Pros

• Promotes excellent bonding when followed by the ultra sealant, which customers report helps stop leaks effectively.
• Clear 16 oz size is practical for targeted repairs on RV roofs and rooftop accessories.
• Easy to use as part of the prescribed two-step system, supporting the sealant's self-leveling and adhesion properties.

Cons

• Limited to use as a primer for TPO, EPDM, and specific plastics, so it is not a standalone sealant or universal adhesive.

Specifications

Product name	Dicor RP-USP-P Ultra Sealant Primer
Volume	16 Oz
Color	Clear
Designed for	Prep for sealing TPO and EPDM membranes
System role	Part 1 of Dicor ultra sealant system
Primary use	Priming plastic appliances and roofing materials

Our Verdict

For anyone using Dicor ultra sealant on RV roofs or rooftop appliances, this primer is a necessary and good-value step that improves adhesion and long-term sealability. It is not a universal adhesive, but when paired with the matching sealant it helps create reliable, leak-resistant repairs and routine maintenance results.

Frequently Asked Questions

Is this primer required before using Dicor ultra sealant?
Yes. It is specified as Part 1 of the system to prepare TPO, EPDM, and compatible plastics so the sealant can bond properly.

Will the clear primer change the look of my RV roof?
No. The clear formulation is intended to leave appearance unchanged while improving adhesion for the sealant.

Can this primer be used on vertical surfaces?
The primer prepares surfaces for the sealant, and customers report the combined system stays put even on some vertical surfaces when applied as directed.