Silicone vs. Polyurethane Sealants: AI’s Recommendation

Silicone vs. Polyurethane Sealants

There’s nothing more Aussie than having a go at a home DIY project. But when you’re faced with a wall of sealants at the hardware store, it’s easy to feel overwhelmed. Choosing the wrong one can lead to leaks, mould, cracking, and a job that needs redoing in no time.

At Caulk It, we know that the difference between a lasting repair and a recurring headache often comes down to one choice: silicone or polyurethane? As Australia’s trusted sealing experts, we use Premium Simseal Products to ensure flawless results. This guide breaks down the key differences, so you understand exactly what we use and why for your project.

The Quick Aussie Answer: Which One Do You Need?

Got a bathroom, kitchen, or wet area? You need Silicone (We use Simseal SS100).
Sealing windows, brickwork, or something you need to paint? You need Polyurethane.
Filling gaps in weatherboards or architraves? A versatile Gap Filler is your best bet.
Working on a roof, facade, or in full sun? A high tech Hybrid Sealant like Simflex Facade is the ultimate choice.

Understanding the Contenders: Silicone vs. Polyurethane

Silicone Sealant: The Flexible Waterproof Champion

What it is: A synthetic rubber that cures into a super flexible, waterproof barrier. It’s the go to for wet areas.
Why we use it: Nothing beats it for mould resistance and permanent flexibility. It moves with your home through hot Aussie summers and cool winters without cracking.

Best For:

Bathrooms, showers, vanities, and sinks
Kitchen splashbacks and benchtops
Internal corners and wet areas
Glass, tiles, and porcelain

Limitations:

Not paintable: Paint simply won’t stick to it.
Surface specific: Bonds best to non-porous surfaces.

Our Go To Product: Simseal SS100 Neutral Sanitary Sealant

We use this in virtually every wet area job. It’s:

100% Mould Resistant: Formulated with anti-fungicide to stand up to humid Aussie climates.
Food Safe: Perfect for kitchens.
Stays Flexible: Handles joint movement without failing.
Low Odour & Low VOC: Better for your home and our environment.

Polyurethane Sealant: The Tough, Paintable Workhorse

What it is: A tough, durable sealant that cures into a rigid, rubber like finish. It’s incredibly strong and sticks to almost anything.
Why we use it: Its superior adhesion and paintable finish make it ideal for structural and exterior jobs.

Best For:

Exterior windows and door frames
Roofing, gutters, and downpipes
Brickwork, concrete, and rendering
Driveways and expansion joints

Limitations:

Less flexible: Can become brittle and crack over time if there’s significant movement.
UV degradation: Can break down in direct sun unless painted over.
Messy application: Requires solvents for cleanup and has a strong smell.

Beyond the Basics: Other Essential Simseal Products

For a complete sealing solution, we also rely on these two other champions from the Simseal range:

Simseal Gap Filler

Type: Acrylic Latex
Best For: The all rounder for general household gaps. Perfect for filling cracks in cornices, skirting boards, interior walls, and door frames.
Why We Use It:
- Paintable: Can be over painted in just 60 minutes.
- Easy Clean Up: Water-based, so tools and mess clean up with water.
- Low Odour: Great for quick indoor jobs where you can’t vacate the room.

Simflex Facade MS Polymer Sealant

Type: Advanced Hybrid Polymer (MS Polymer)
Best For: The ultimate professional solution for exteriors, roofs, cladding, and coloured joints.
Why We Use It:
- The Best of Both Worlds: Has the flexibility of silicone and the paintable, non-staining properties of polyurethane.
- UV & Weather Resistant: Specifically formulated for the harsh Australian sun.
- Stain Free: Silicone oil-free, so it won’t stain stone or render.
- Superior Movement: Handles up to ±50% joint movement, perfect for our expanding and contracting buildings.

Why Australian Homeowners Trust Caulk It

Choosing the right product is only half the battle. Proper preparation and application are what make the seal last. That’s where we come in.

The Caulk It Process:

Assess: We check your substrates, joint sizes, and exposure to sun and weather.
Select: We choose the right product from our commercial grade Simseal range.
Prepare: We clean and prime surfaces to professional standards this step is 90% of a good job!
Apply: Our technicians apply and tool the sealant for a perfect, waterproof finish that lasts for years.

We don’t just sell you a product; we provide a guaranteed solution.

DIY Tips from the Pros

If you’re having a go:

Test First: Always try the product on a small, hidden area first.
Prep is Key: Surfaces must be spotlessly clean, dry, and free of dust, oil, and old sealant. Use methylated spirits for silicone and the correct primer for polyurethane.
Watch the Weather: Don’t apply sealant in rain, extreme heat, or direct hot sun.
Tool for a Perfect Finish: Use a tooling tool or a wet finger to smooth the bead for a professional look.

Why Hire Caulk It?

Save Time & Money: No wasted trips to the shops or botched jobs.
Guaranteed Workmanship: We warranty our labour and the materials.
Access to Pro Products: We use higher performance sealants than you’ll find on retail shelves.
Perfect Results, First Time: Get a flawless, durable finish that adds value and protection to your home.

Ready to Banish Leaks and Draughts for Good?

Don’t let the Aussie weather get the better of your home. Whether it’s a leaking shower, draughty windows, or cracked render, Caulk It has the expertise and the premium Simseal products to fix it for good.

Get a free, no obligation quote today and see why we’re Australia’s trusted sealing experts.