Repair Systems — 03 — Facade & External Envelope
Dymonic FC one-part high-movement polyurethane sealant
Technical product reference for Tremco Dymonic FC one-part moisture-curing polyurethane sealant specifically designed for facade masonry applications. Accommodates ±35% movement at low modulus (Shore A ~25A) — higher movement class and lower modulus than standard one-part ISO 11600 F 25 LM products. Gun-grade, no mixing, fuel-resistant. Widely specified on Australian masonry facade remediation projects. Primer and bond breaker backer rod required.
What is Tremco Dymonic FC high-movement polyurethane sealant?
Tremco Dymonic FC is a one-part moisture-curing polyurethane sealant specifically designed for facade masonry applications requiring high-movement accommodation. Accommodates ±35% joint movement at low modulus (Shore A ~25A) — lower modulus than standard one-part PU products. Gun-grade, no mixing. Fuel and oil resistant. Primer required on porous masonry substrates. Widely specified on Australian masonry facade remediation projects.
Supplier reference — Tremco Dymonic FC high-movement sealant
Tremco Dymonic FC one-part high-movement polyurethane facade sealant
Premium one-part moisture-curing PU sealant — ±35% movement accommodation — specifically designed for facade masonry applications — low modulus (~25A Shore) — fuel-resistant — widely specified in Australia
Tremco Dymonic FC — key technical data
| Attribute | Value |
|---|---|
| Supplier | Tremco |
| Product | Dymonic FC |
| Components | One-part |
| Cure mechanism | Moisture-curing |
| Movement accommodation | ±35% |
| Shore A hardness (cured) | ~25A (low modulus) |
| Fuel resistant | Yes |
| Paintable | Confirm with current TDS |
| Primer required | Yes — Tremco Primer 171 on porous substrates |
| Bond breaker required | Yes — PE foam backer rod |
| Colour range | Wide range available |
| Traffic bearing | No |
- High-movement masonry facade movement joints where standard ±25% accommodation is insufficient
- Wide or thermally active movement joints in masonry facades on north and west-facing elevations in Australian climate
- Facade joints in proximity to plant rooms, service areas, or parking structures where fuel and oil resistance is required
- Specify Dymonic FC when ±35% movement is required from a one-part product — avoids two-part mixing complexity
- Low modulus (~25A Shore) makes Dymonic FC particularly suited to facades with high thermal cycling and large joint spans
- Confirm primer is Tremco Primer 171 on masonry substrates — do not substitute with other brand primers
- Bond breaker backer rod at the joint base is mandatory — three-sided bond restricts movement and causes tearing
- Do not apply to wet joint faces — substrate must be clean, dry and primed
- Moisture-curing — will cure slowly in very dry or cold conditions; confirm minimum application temperature
- AS 3700 — Masonry Structures — movement joint spacing and sealant requirements for masonry facades
- ISO 11600 — Classification and requirements for joint sealants — confirm product movement class from current TDS
- NATSPEC worksection 05 32 00 — Sealants — project specification requirements for sealant work
- Failed polyurethane sealant in high-movement masonry facade movement joints where standard ±25% products have failed in service
- Open or deteriorated control joints in facades with high thermal exposure or large panel sizes
- Perimeter joints around window and door frames in thermally active facades
- Modern fired clay brick — prime with Tremco Primer 171 before sealant application
- Concrete masonry units and precast concrete panels — prime per Tremco TDS
- Rendered masonry facades — confirm render is cured, clean and primed before sealing
Do not confuse Dymonic FC with:
- Sikaflex-11FC+ — one-part PU by Sika rated only ±25% movement (ISO 11600 F 25 LM); use Dymonic FC where ±25% is insufficient for the expected joint movement range
- Mapeflex PU45 — a two-part polyurethane sealant by Mapei rated ±35% HM; requires A+B mixing on site; higher modulus than Dymonic FC; use where two-part mixing is appropriate for the application
- Silicone sealants — silicone is not paintable after cure; do not substitute silicone for polyurethane on joints that will receive a painted topcoat
- Polysulfide sealants — a different polymer chemistry with different adhesion and movement characteristics; not directly interchangeable with polyurethane on masonry movement joints
- Traffic-grade polyurethane sealants — Dymonic FC is not rated for traffic-bearing joints; specify a traffic-grade product for vehicle-trafficked areas
Disclaimer
This page provides general technical information only. Sealant selection, joint geometry, primer requirements and movement class must be confirmed against the project's joint design, substrate type and exposure conditions per ISO 11600 and AS 3700. Confirm current product data with the Tremco TDS before specifying or applying.