SlabCollar™ 4" EPDM Radon Pipe Penetration Seal — Fits 5" Cored Holes

The drop-in seal for 4" radon pipe through a 5" cored hole

SlabCollar™ is a one-piece flanged EPDM bushing that seals the gap between a 4" Schedule 40 radon vent pipe and a 5" cored slab opening. It replaces messy caulk-and-backer-rod sealing and outperforms thermoplastic compression bushings — without the precision a perfect cored hole demands.

Designed for C-NRPP-certified mitigators. Installed by feel, in under a minute. No mixing, no curing, no callbacks.

Why mitigators are switching to SlabCollar

• Flanged seal, not just a bushing. The 6-1/8" top flange rests flat on the slab and covers chipped or oversized cored-hole edges that compression bushings can't hide. You get a primary seal in the hole and a secondary seal against the slab surface — both in one part.
• Forgiving on real-world holes. Cored hole came out a little oval? Edge chipped? SlabCollar's EPDM body flexes to seal openings that rigid thermoplastic bushings can't. Less time chasing leaks with a smoke pencil.
• Holds the pipe, not just seals it. Engineered to a specific durometer that balances flexibility (so the flanges seal imperfect holes) with the firmness needed to grip the pipe. In bench testing, a collar with a 4" Sch 40 stub through it supported a 240 lb adult standing on the pipe with no deformation. Bracing is still required per CGSB 149.12 — but you get a fit that doesn't loosen the first time someone bumps the stub.
• Removable for service. When a sump or suction pit needs work, SlabCollar pulls out clean and goes back in. No grinding out hydraulic cement. No re-caulking the joint on the way out.
• No caulk required. EPDM compression seals against concrete and pipe on contact. Skip the urethane tube, skip the cure time, skip the cleanup.
• EPDM, not generic thermoplastic. Engineered for −40°C to +120°C operating range and the 25+ year service life EPDM is known for in roofing and sub-slab applications. No cold-weather brittleness. No UV degradation.

Built for C-NRPP installations

SlabCollar meets the airtight-seal expectations of CGSB 149.12-2017 for active soil depressurization systems. Pairs with any 4" Schedule 40 PVC or ABS radon vent pipe, any radon fan, any sub-slab pit configuration.

How to install

1. Core a nominal 5" hole through the slab. Clean dust and debris.
2. Press SlabCollar into the hole, flange seated flat against the slab surface.
3. Slide 4" Sch 40 pipe through the collar. Brace pipe per CGSB 149.12 (the collar is not a structural support).
4. Run a smoke pencil under fan suction to verify the seal. Done.

Bulk pricing for radon professionals

Verified C-NRPP and CARST mitigators get contractor pricing on case quantities. Create a pro account to access wholesale rates.

Frequently asked questions

Is SlabCollar a direct replacement for the U-Stop?
Yes — SlabCollar is the first product that is designed for the specific use. Other products that have been used for years were never designed for this application, and as a results do not hold an adequate airtight seal.
Unlike others - SlabCollar adds a top flange that covers the slab edge, uses EPDM instead of generic thermoplastic, and 2 outer flanges giving it 3 different airtight connections so that it can seal airtight even if the concrete hole is uneven, and is also engineered to grip the pipe under load to make installations easier.

Do I need to use caulk with SlabCollar?
No. The EPDM compression seal is designed to be airtight on its own. A thin urethane bead at the flange edge is optional belt-and-suspenders.

What if my hole isn't perfectly 5"?
The EPDM body and flange combination tolerates moderate hole irregularity. Significantly oversized or damaged holes should be patched before installation.

Is there a fire-rated version?
A fire-rated EPDM variant for NBC Article 3.6.4.3 applications is in development. Contact us for project-specific requirements.

What about 3" pipe?
A 3" SlabCollar is in production. Email us to be notified at launch.