Greater London · England
Glazing Silicone in Blackfen
Glazing silicone for conservatories, rooflights, glass panels and shower screens in Blackfen, with a one-year guarantee on every job. Call for a quick quote.
- Mouldy sealant around glass panels
- Rooflight joints letting water in
- Failed joints on frameless glass
Why act early in Blackfen
Topping up old silicone can look like a fix, but new silicone won’t bond to old and water soon finds its way back. Cutting out and resealing properly lasts. In a London flat, a failed joint rarely stays your problem alone: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
Commercial jobs are quoted on the same basis as homes: the amount of work, how we reach it and what it needs, along with when we can work on site. Call for a quick quote and we will go through it with you.
Why choose Mr Mastic in Blackfen
- More than 20 years in sealant work
- We agree the colour with you first
- We leave the area clean and tidy
- ARBOMaster approved applicator
Take a look at what affects the cost or our reviews.
Glazing silicone in Blackfen
Not every silicone suits glass. Our applicators use neutral-cure glazing silicone, which suits glass and most frame materials, and we tool it to a neat, even finish. We work on glass-to-frame joints, conservatory frames and rooflights, and common reasons people get in touch are black or yellowed silicone on glass joints and water running down inside the glass.
London has a lot of flats and conversions, where windows are often on upper floors. In a converted house or block, the lease normally says who is responsible for the windows, so it’s worth checking before booking, and access in Blackfen is something to talk through when you book.
We stand behind the work with a one-year guarantee, so you’re not left on your own once the job is done.
- Place
- Blackfen (DA15, DA16, SE9)
- Region
- Greater London
- Cover
- One year on every job
- Quote
- A clear quote up front
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Nearby places to Blackfen
What else we do in Blackfen
How the visit works
At the end, we look at the finished work together and tell you how long to leave it. The work normally takes anything from an hour or two to most of a day, depending on the size of the job, depending on how much there is to do. In Blackfen, flats, stairs and shared entrances are part of the routine. If the building has a concierge, managing agent or access rules, tell us when you book.
- We start by finding the leak and making sure sealant is the cause.
- The old sealant is removed from the glass and frame without scratching them.
- Surfaces are cleaned with a solvent suited to glass and the frame.
- New glazing silicone goes in and is tooled to a neat finish.
- We look over every joint and, where we can, test it with water.
How to prepare
- Clear items away from the joints we are working on
- For indoor joints, keep the area dry beforehand if you can
- Let us know about stairs, lifts or work at height
Get a quote
For a quick quote, get us on the phone, or email us if that’s easier. Tell us about the joints that need doing and we’ll talk you through the work.
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What we cannot put right
It helps to know what we can’t do too:
- A sealed unit that has misted inside
- Water coming through the roof rather than a sealant joint
- Rotten or badly damaged frames
If you are not sure, just phone 0345 464 0079 or send us an email and we will give you a straight answer.
What we seal
- Rooflights
- Glass-to-glass joints
- Conservatory frames
- Glass-to-frame joints
- Glass balustrade bases
- Shower screens
Common problems we fix in Blackfen
Heat and cold make glass and frames move, and they don’t move by the same amount. Over years, that movement tears the silicone.
The problems people usually mention when they call include:
- Black or yellowed silicone on glass joints
- Rooflight joints letting water in
- Glass-to-glass joints that have split
- Split or lifting silicone on glass
For site and facilities teams at buildings such as Our Lady of the Rosary Catholic Primary School, the mastic around its windows and doors needs looking after like any other building’s.
Comparing quotes
- What happens if they find a problem under the old sealant
- How long the guarantee is
- How the colour is chosen
- How long to leave it before use
How the job changes by surface
Conservatory frames
Frame-to-wall joints on a conservatory move with the weather. They’re resealed with a suitable sealant.
Rooflights
Rooflight leaks can come from the sealant or the roof. We find the cause first.
Quotes for glazing silicone in Blackfen
The price is agreed before any work begins. It takes into account:
- Working hours on commercial sites
- The type of sealant required
- Access and height
- The number and length of the joints
What it costs depends on the size of the job, how much old material has to come out and how easy the joints are to reach. We give a clear quote before we start.
Asking for a quote
Before you ask for a quote, have a think about:
- Where the job is, and your postcode
- What’s wrong with the joints now
- How many joints, rooms or windows are involved
- How we’d reach the joints
For a quote, call 0345 464 0079 or drop us an email with the location and a short description of the problem. You’ll have a clear quote before we start.
DIY versus a professional finish
If you are set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and doesn’t move well, and getting the depth right matters as much as the look.
Your questions about glazing silicone in Blackfen
Can you do glazing silicone in Blackfen?
Yes, Blackfen is within the area we cover. We work across London and the South East. Just phone 0345 464 0079 or drop us an email with a few details of the job.
I let a flat near Falconwood station. Can you help?
Yes, we work for letting agents and landlords. Just phone 0345 464 0079 or email us and tell us about the property, and we will give you a clear price.
Which silicone is used for glass joints?
We use a neutral-cure glazing silicone suited to glass and the frame. Shower screens get anti-fungal silicone.
Will it make a mess?
Very little: the area around the joints is protected first, and we tidy up before we go.
Do you remove the old sealant?
Yes, every time. New silicone does not stick to old silicone, so any old material comes out before anything new goes in.
What do you put in the joint?
Products from Arbo and Everbuild, among others, chosen to suit the joint. We’ll tell you what we are using and why.
Is there any odour?
Some sealants have a smell while they cure. Opening a window helps.
Do you have insurance?
Yes. We are fully insured, and we’ve been doing sealant work for more than 20 years.
Windows and doors in Blackfen
In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking. The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Homes close to Church of the Good Shepherd include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall. Blackfen is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Blackfen is about 2 miles east of Eltham, in Greater London. If you need glazing silicone in Blackfen, it’s easy to get a quote: please phone 0345 464 0079 or send us an email. We cover Greater London from our Crawley base, Blackfen included. Blackfen is one of 764 towns and villages in Greater London we cover. London is on our list too, around 9 miles away.
All of DA15, DA16 and SE9 is covered for glazing silicone, from the main roads to the quietest streets. That includes homes and businesses on Days Lane, Gordon Road and Kent Avenue. Other places close to Blackfen include Falconwood (1 mile north), Avery Hill (1 mile west), East Wickham (1 mile north), New Eltham (1 mile south-west) and Longlands (1 mile south). Within a short drive, we also cover London (9 miles north-west), City of Westminster (11 miles north-west), Marylebone (11 miles north-west), Kensington (13 miles west), St Pancras (10 miles north-west) and Shoreditch (9 miles north-west).
Local landmarks in Blackfen
Locally, jobs take us to homes and businesses close to The George Staples pub, Harris Academy Falconwood and Shoulder of Mutton Green, among other places. The nearest railway station is Falconwood station, roughly 0.8 miles north-west of the centre. Other landmarks nearby include Broadway Shopping Centre (2.3 miles east) and Eltham Community Hospital (1.7 miles west). For a walk, there’s Summer Hill and The Tarn.