Let's be honest, you probably haven't spent much of your life daydreaming about the price of mastic. But the moment you spot a leaky shower tray or a draughty commercial window, suddenly, the silicone sealant cost UK property owners pay becomes a very hot topic. It might just be a tiny bead of silicone, but it has a surprisingly big impact on your wallet if it fails.
In this guide, we'll walk you through exactly what you can expect to pay in 2026. We'll cover the cost of materials and labour, the difference between domestic and commercial projects, and why repairing an old bodge job usually costs more than applying it fresh.
At Gould Silicone Sealants, we've been applying silicone and mastic sealant for over 40 years across the UK. We handle everything from a single sticky bathroom situation to massive commercial glazing perimeters. So, grab a cuppa, and let's look at what that perfect, waterproof seal is actually going to cost you.
What you're actually paying for (it's not just a tube of goo)
Materials and sealant type
First up, let's clear up the terminology. People often use "silicone" and "mastic" interchangeably. Generally, silicone is highly flexible and water-resistant, making it perfect for bathrooms and glazing. Mastic is a broader term for a sticky, waterproof jointing material often used for wider gaps.
The category of sealant dictates the price. A basic bathroom sealant with mould inhibitors is relatively cheap. However, external weather-sealing formulas that resist UV rays, structural glazing silicones, or fire-rated sealants designed to stop flames spreading will cost considerably more per cartridge.
Prep work (the unglamorous bit that makes it last)
Nobody likes scraping out old sealant. It's tedious, messy, and absolutely essential. If we just apply new silicone over old, damp, mouldy mastic, it'll fail almost immediately. You're paying us to carefully slice out the failed sealant, clean the area with specialised solvents, dry it perfectly, and treat any mould. We also mask the edges to ensure those lines are razor-sharp.
Labour, skill and finish quality
Applying sealant looks incredibly easy on YouTube. In reality, getting a smooth, consistent, bubble-free bead requires serious muscle memory. You're paying for trained, certified professionals who deliver a tidy finish. A messy finish isn't just ugly; it creates little ridges where water pools and mould breeds.
2026 sealant price guide UK: cost ranges by common project
Here is a quick look at our sealant price guide UK for 2026. Please note that these are rough estimates, as every job is unique.
Domestic examples
Bath / shower tray reseal: £80 – £150 (includes removal of the old sealant).
Kitchen worktop and splashbacks: £100 – £180 (depending on the size of the kitchen).
Windows and doors (internal/external): £150 – £300+ for an average house.
Small repairs: Often subject to a minimum call-out charge (usually around £75 – £100).
Commercial examples
Expansion joints (external): Priced per linear metre, highly dependent on access equipment.
Curtain wall / glazing perimeters: Usually requires a site survey to quote accurately based on day rates or metreage.
High-traffic wet areas (gyms, hotels, schools): Often quoted as a block package to ensure minimum downtime.
Ongoing maintenance: We offer retained maintenance contracts to keep commercial spaces compliant year-round.
Factors that change the price
Why might your quote be higher or lower than your neighbour's? Here are the main culprits:
Job size: The total linear metres of jointing we need to seal.
Access: If your windows are three storeys up, we'll need scaffolding or a cherry picker, which increases the cost.
Location: We travel across the UK, but very remote projects might incur travel costs.
Internal vs external: External jobs rely on the Great British weather and often require highly specialised weather-resistant silicones.
Condition: Ripping out rock-hard, 20-year-old mastic takes hours. Fresh application on a new build is much faster.
Colour matching: Need a highly specific matt anthracite to match your bespoke tiles? Custom colours cost a little extra.
Urgency: Need us to work overnight so your restaurant can open at 8 AM? Out-of-hours work carries a premium.
DIY vs professional application: when saving money costs more
If you have a tiny cosmetic gap around a skirting board, by all means, grab a £5 tube and have a go. DIY is great for low-risk, dry areas.
However, you should definitely call us for areas prone to leaks (showers, baths), external weatherproofing, commercial compliance, and absolutely anything involving fire-rated sealants or structural glazing. The most common DIY pitfalls we see are poor adhesion (because the area wasn't cleaned), movement cracks, trapped moisture, and lines that look like a toddler drew them.
Before you DIY, ask yourself: Can I afford to fix the water damage if this fails? If the answer is no, call the pros.
How to get the best value (without sacrificing quality)
Getting a good deal doesn't mean hiring the cheapest person you can find on a local community group. To get the best value, make sure you choose the right sealant for the environment. Don't use a basic internal mastic on an external weather joint.
Prioritise the prep work. Ask your applicator what their process is. Ask about the expected longevity of their work. If you have several areas that need doing, bundle them together into one job. We can seal your bathroom, kitchen, and patio doors in a single visit, saving you money on multiple call-out fees.
Why work with us
At Gould Silicone Sealants, we aren't just a bloke with a van and a half-empty tube of silicone. We are a family-run business with over 40 years of hands-on experience. We cover both commercial and domestic projects across the whole of the UK.
We only use durable, highly flexible, weather and UV-resistant materials. Our team is friendly, reliable, and obsessed with leaving a tidy finish. We offer highly competitive pricing and fast turnarounds, all backed by a satisfaction-focused service. Want to know more? Just head over to our contact page for a chat.
FAQs
What is silicone/mastic sealant?
It's a flexible, waterproof, adhesive compound used to fill gaps and joints between building materials, allowing for slight movement while preventing water or air ingress. It can be used to seal and protect a wide range of interior and exterior surfaces such as glass and steel and prevent the ingress of rain water and other liquids.
How long does silicone/mastic sealant last on wet surfaces?
A high-quality, professionally applied sealant can last anywhere from 10 to 20 years. In high-use, wet areas like showers, it usually needs replacing every 5 to 10 years.
How do I know if I need silicone/mastic sealant services?
Look out for black mould that won't clean off, peeling or cracked sealant, draughts around windows, or the dreaded damp patches on ceilings below your bathroom.
Is mouldy sealant always a sealing issue or a ventilation/cleaning issue too?
Mould feeds on soap scum and dampness. While old sealant degrades and becomes porous, poor ventilation and a lack of regular cleaning will make even the best sealant go black eventually.
Can you colour match sealant to my worktop/tile (gloss or matt)?
Yes! We offer extensive colour matching services, including gloss, matt, and even specialised RAL colours for commercial glazing to ensure a perfectly seamless finish.
Do you handle commercial specialist sealants?
Absolutely. We are fully trained and equipped to handle structural glazing, high-grade weather sealing, and crucial fire-protection (intumescent) sealants.
Get a tailored quote (and stop guessing)
Still wondering exactly what your specific project is going to cost? Stop guessing and let us give you an exact number. Whether you've got a single shower that needs saving from the mould monster, or a multi-storey office block that needs full external weather sealing, Gould Silicone Sealants is ready to help with a huge stock of different sealants for all manner or projects.
We provide free, no-obligation quotations and estimates. Give us a call, drop us an email, or fill out our contact form today. If you can, send over a few photos and rough measurements—it helps us get your tailored 2026 price guide back to you even faster!
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