Repair Systems — 03 — Facade & External Envelope
Polyurethane sealant — one part
Technical product reference for one-part polyurethane sealant systems used in facade movement joint, control joint and perimeter joint remediation on Australian Class 2 strata buildings. Covers product classification, system selection, application requirements and brand comparisons.
What are one-part polyurethane sealant systems?
One-part polyurethane (PU) sealants are single-component, moisture-curing elastomeric sealants widely used in Australian facade remediation for movement joints, perimeter joints and control joints. Unlike two-part PU systems, they require no mixing and cure on contact with atmospheric moisture. They are flexible when cured, accommodating thermal and structural movement, and most one-part PU sealants are paintable — an important advantage over silicone sealants where the sealant joint must be over-painted.
Product Reference
3 products — 3 brands — one-part polyurethane facade sealant systems — scroll to view all
System Description
Sikaflex-11FC+ is a one-part, moisture-curing polyurethane construction sealant suitable for facade movement joints, control joints, perimeter joints and general sealing in Australian Class 2 strata remediation. It cures without mixing, directly from the cartridge, making it practical for on-site application by a trades team. Sikaflex-11FC+ bonds to most construction substrates including concrete, masonry, render, aluminium, and most paints without a primer on clean and dry surfaces. It accommodates ±25% joint movement, is UV-resistant, and can be painted over with most architectural paints once cured. For best results, ensure joint is clean, dry and free of existing sealant residue, and apply with a backer rod behind the sealant for joints deeper than 8mm to ensure correct sealant profile and prevent three-sided adhesion.
Technical Properties
- One-part — no mixing required — ready to use from cartridge
- ±25% movement accommodation (ISO 11600 Class F-25LM)
- Paintable after cure with most architectural paints
Limitations
- Not suitable for structural glazing (use structural silicone for glass-to-frame structural bonding)
- Not suitable for permanently submerged joints (use polysulfide or dedicated pool sealant)
- Moisture-curing — do not apply in wet conditions or on wet substrates
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Tremco Vulkem 116
One-part moisture-curing polyurethane sealant — high-movement facade
System Description
Tremco Vulkem 116 is a one-part moisture-curing polyurethane sealant designed for building facade joints, expansion joints and perimeter sealing. Vulkem 116 is widely used in commercial and strata facade remediation in Australia. It offers higher movement accommodation than many one-part PU systems and is suitable for wide movement joints. Primer (Tremco 636 or equivalent) may be required on porous substrates for optimal adhesion — confirm substrate-specific primer requirements with Tremco Australia technical. Ensure backer rod is installed behind sealant for proper joint geometry and to prevent three-sided adhesion. TODO: owner confirm — confirm current Australian product designation, primer requirements and movement class with Tremco Australia technical.
Technical Properties
- One-part moisture-curing — no mixing required
- High movement accommodation — confirm rating from current TDS with Tremco technical
- Suitable for facade movement joints, expansion joints and perimeter seals
Limitations
- Primer may be required on some substrates — check with Tremco technical
- Not suitable for permanently submerged applications
- Do not apply on wet or frozen substrates
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Description
Bostik Seal N Flex 1 is a one-part polyurethane construction sealant suitable for sealing movement joints in masonry, concrete, render and similar substrates. It is UV-stable and can be overpainted once cured. Bostik Seal N Flex 1 is widely available through hardware and trade channels in Australia. Confirm movement accommodation class, primer requirements and specific substrate compatibility from the current Bostik TDS before specifying. Confirm suitability for facade-grade movement joints in Class 2 strata with Bostik Australia technical. TODO: owner confirm — confirm movement accommodation class, primer requirements and suitability for Class 2 strata facade joints with Bostik Australia.
Technical Properties
- One-part — no mixing — ready to use
- UV-stable — suitable for exposed facade joints
- Paintable after cure with most architectural paints — confirm with Bostik
Limitations
- TODO: owner confirm — confirm movement accommodation class (±15% vs ±25%) with Bostik Australia technical
- Not suitable for structural glazing
- Not suitable for permanently submerged applications
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Comparison
Side-by-side comparison of one-part PU sealant systems. Confirm all product selections against the current manufacturer TDS before specifying.
| Product system | Brand | Components | Movement | Paintable | Primer | Primary use |
|---|---|---|---|---|---|---|
| Sikaflex-11FC+ | Sika | One | ±25% | Yes | Usually not required | Facade movement joints, perimeter sealing, masonry and concrete |
| Vulkem 116 | Tremco | One | High — confirm TDS | Yes — confirm | May be required — confirm | Facade movement joints, expansion joints — higher movement applications |
| Seal N Flex 1 | Bostik | One | Confirm TDS | Yes | Confirm TDS | Masonry and concrete facade joints — general sealing |
Do not confuse one-part polyurethane sealant with:
- Two-part polyurethane sealant (mixed A+B components — different pot life, higher performance for some applications — listed on the two-part PU sealant page)
- Neutral cure silicone sealant (different chemistry — silicone is superior for glazing, aluminium and UV exposure but less paintable — listed on the neutral cure silicone page)
- Polysulfide sealant (different chemistry — used in aviation fuel tanks and pool joints, older product in facade use — listed on the polysulfide sealant page)
- Acetic-cure silicone (releases acetic acid on cure — attacks metals — NOT suitable for facade joints or aluminium substrates)
- Cement-based grout (rigid — no movement accommodation — not a sealant system)
Disclaimer
This page provides general technical information only. Final product selection must be confirmed against the current manufacturer technical data sheet, project specification, substrate condition, exposure classification and applicator warranty conditions. Products marked TODO: owner confirm require verification before specifying. Do not rely on this reference as a substitute for professional engineering or facade consultant advice.