If you look around the room you’re sitting in right now, there is a very high chance you are within a few metres of some silicone sealant. It’s holding your windows in, it’s stopping your bathtub from leaking through the ceiling, and it’s keeping the draft out of your skirting boards.
Yet, despite being the unsung hero of the construction world, most people don’t give it a second thought—until it goes wrong, turns black with mould, or starts peeling away like string cheese.
At Gould Silicone Sealants, we think about sealant a lot. Probably too much. As a family-run business covering Kent, London, Derby, and the South East, we’ve spent over 40 years perfecting the art of application. We’ve seen the good, the bad, and the incredibly sticky.
But what exactly is this rubbery wonder-stuff? In this guide, we’re going to break down exactly what silicone sealant is, exploring the different silicone sealant uses, and helping you decide when to call in the professionals (that’s us) for your next project.
What is silicone sealant?
Let’s start with the basics. Silicone sealant (sometimes called silicone glue) is a powerful, flexible adhesive that looks like a liquid gel when it comes out of the tube but cures into a tough, rubber-like solid.
Unlike other adhesives that are designed to stick two things together rigidly (like superglue), silicone is designed to maintain its elasticity and smooth surface pattern. It’s chemically distinct because it’s made from silicone polymer, which gives it some pretty impressive superpowers:
It’s waterproof: Water rolls right off it.
It’s flexible: Buildings move, expand, and contract with heat. Silicone moves with them without cracking.
It’s highly resistant: It doesn’t melt in the summer or snap in the winter.
It’s UV stable: The sun won’t break it down easily.
It comes in a few colours: Normally white, brown or black to match your desired paint colour.
In short, it is the barrier that keeps the outside out and the inside dry.
Common uses of silicone sealant in commercial projects
You might think sealant is just for the edge of a bathtub, but in the commercial world, it’s keeping massive structures functional. When we work on silicone sealant projects in the commercial sector, the stakes are usually higher (sometimes quite literally).
Commercial construction
In large-scale construction, expansion joints are vital. Concrete slabs and brickwork shift over time. If you filled the gaps with cement, the building would crack. We use specialist structural silicone to fill these gaps, allowing the building to "breathe" and move without compromising its integrity.
High rise buildings
If you’ve ever looked up at a glass skyscraper in London, you’re looking at kilometres of silicone. Structural glazing relies on high-strength silicone to hold glass panes in place against high winds and driving rain. It’s not a job for the faint-hearted, but it’s one we handle with precision.
Bespoke projects
From swimming pools in leisure centres to sterile environments in hospitals, commercial projects often require bespoke solutions. We often provide colour-matched silicone to blend seamlessly with marble, stone, or specific RAL colours of window frames. It’s about functionality, but it’s also about aesthetics.
Weatherproofing
External facades take a beating from the British weather. Commercial silicone application ensures that rain, sleet, and snow don’t penetrate the building envelope, protecting the expensive assets inside.
Common uses of silicone sealant in domestic projects
Now, let’s bring it closer to home. Silicone sealant uses in a domestic setting are usually focused on hygiene and waterproofing.
Bathrooms
This is the classic habitat of the silicone bead. You’ll find it sealing the gap between the tiles and the bath, shower tray, or basin. In this environment, the sealant needs to contain fungicides to stop that dreaded black mould from appearing. If your current sealant looks a bit like a science experiment, it’s time to strip it out and replace it. Check our bathroom sealants blog for more details.
Kitchens
Kitchens are messy places. Crumbs, water, grease, and sauce get everywhere. A high-quality food-safe silicone seal behind the sink and along the worktop splashback prevents water from swelling your cabinets and stops food from falling down the back of the units. Check our kitchen sealants blog for more details.
Window and door frames
Drafts are the enemy of a heating bill. We apply frame sealant around the exterior (and interior) of windows and doors to create an airtight and watertight seal. It stops the rain getting in and keeps your expensive heat from getting out.
Small light fixtures
Ideally, you don’t want moisture getting into your electrics. A small, neat bead of silicone around exterior lights or bathroom fittings adds that extra layer of safety.
Alternatives to silicone sealant
While silicone is fantastic, it isn’t the answer to absolutely every problem. Sometimes, you need a different tool for the job.
Acrylic sealant
Often called "Decorators Caulk," this is water-based.
Pros: It’s cheap, easy to smooth, and crucially, you can paint over it (you cannot paint over silicone).
Cons: It isn’t waterproof and it cracks easily if there is too much movement. Use this for skirting boards and door architraves, never for the shower.
Polyurethane sealant
This is the heavy-duty industrial cousin.
Pros: Incredible tear strength and adhesion. It’s great for high-traffic floor joints.
Cons: It can be messy to work with and isn’t always as UV stable as silicone, meaning it can degrade in direct sunlight over time.
Polysulfide sealant
An older technology, but still useful.
Pros: Excellent for underwater applications (like swimming pools) and chemically resistant.
Cons: It takes a long time to cure and smells quite strong.
Types of silicone sealants
Not all tubes of silicone are created equal. If you grab the wrong one, you might find it peeling off in a week or corroding your metal fixtures. Check our blog for more details.
Acidic silicone sealants (Acetoxy)
You’ll know this one by the smell—it reeks of vinegar. As it cures, it releases acetic acid.
Best for: Non-porous surfaces like glass and glazed ceramic tiles. It cures quickly.
Avoid on: Natural stone (it can stain) and certain metals (it can cause corrosion).
Neutral silicone sealants
These release alcohol as they cure, so they have very little smell.
Best for: Almost everything else. It sticks brilliantly to masonry, stone, plastics, and wood. It’s more expensive than acidic cure, but it’s far more versatile and longer-lasting in exterior conditions.
FAQ
How long does silicone sealant last?
If applied correctly by a professional, high-quality silicone sealant can last for 10 to 20 years. However, in a damp bathroom with poor ventilation, it may need replacing sooner if mould takes hold. Exterior sealant eventually degrades due to weathering but should give you a good decade of protection.
What are the benefits of using silicone sealant?
The primary benefits are elasticity and durability. Unlike grout or cement, silicone absorbs movement. If a bathtub settles when you fill it with water, the silicone stretches. If you used a rigid filler, it would crack immediately, leading to leaks.
Is silicone sealant waterproof?
Yes, fully cured silicone is completely waterproof. It is hydrophobic, meaning it repels water. This makes it the only viable choice for sealing wet areas like showers, sinks, and external glazing.
What's the difference between neutral cure and acid cure?
Neutral cure silicone sealant releases non-corrosive byproducts as it cures, making it suitable for sensitive surfaces such as metals and electronics where corrosion could occur. Acid cure silicone, on the other hand, releases acetic acid during curing, which has a strong odour and can corrode certain materials like metal or concrete. Neutral cure is generally preferred for applications requiring material compatibility, while acid cure is ideal for glass and smooth, non-porous surfaces.
Is silicone sealant and silicone caulk the same thing?
Although often used interchangeably, silicone sealant and silicone caulk have slight differences. Silicone sealant is more versatile and elastic, designed for applications where flexibility and durability are key, such as in joints exposed to consistent movement. Silicone caulk, on the other hand, is generally used for filling gaps and caulking cracks and may have less flexibility. Both perform sealing functions but may be optimised for different tasks.
Is silicone sealant suitable for high-temperature environments like saunas?
Yes, certain silicone sealants are formulated specifically to withstand high temperatures and are suitable for environments like saunas or industrial settings. These high-temperature versions resist heat without losing their elasticity or durability, ensuring a reliable seal even under extreme conditions. Always check the product specifications to ensure it is designed for elevated temperature applications.
Is silicone sealant multi purpose?
Silicone sealant is indeed multipurpose and can be used in a wide range of applications. It is effective for sealing joints in kitchens, bathrooms, and various plumbing tasks. It is also suitable for outdoor applications like window glazing, sealing door frames, and weatherproofing. Depending on the formulation, silicone sealants can cater to specialised needs, including heat resistance, underwater sealing, or compatibility with sensitive materials.
Conclusion
So, there you have it. It might just look like a squishy rubber line, but silicone sealant is an engineering marvel that keeps our buildings dry, warm, and standing tall. Whether it’s sealing a skyscraper against a storm or just stopping your shower leaking into the kitchen below, it’s an essential part of modern construction.
However, applying it is harder than it looks. We’ve all seen the "DIY disasters"—wobbly lines, messy smears, and gaps that leak after a week.
If you have a project that needs a professional touch, don’t risk the mess. With over 40 years of experience, Gould Silicone Sealants can ensure a perfect, watertight, and aesthetically pleasing finish every time.
Need a mastic man you can trust? Get in touch with Gould Silicone Sealants today for a free quote on your domestic or commercial project.
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