Greater London · England
Glazing & conservatory sealant in Northwood, Greater London
Professional glazing silicone in and around Northwood, with old sealant always removed completely.
- Leaking glazing joints on a rooflight
- Shower screens leaking along the wall or tray
- Glass-to-glass joints that have split
Why act early in Northwood
Resealing can’t fix a failed unit or a cracked panel. We say so plainly, so you can call the right trade. Converted houses in London often have a bathroom above someone else’s living room, and a slow leak from a failed seal can end up in the flat below. Putting it right early is much less trouble.
Some things make a job bigger or smaller: the old material and how easily it comes out, whether mould needs treating, and whether we need extra access for height. Your quote takes all of that into account.
Why choose Mr Mastic in Northwood
- Approved under the ARBOMaster scheme
- Homes, businesses and hotels
- 20+ years of sealant experience
- Colour picked to suit the job
See our cost guide and our reviews.
How we handle glazing silicone in Northwood
Our work covers conservatory joints, rooflights and glass panels, as well as frameless shower screens and glass balustrade bases. Each joint is cut out, cleaned and resealed. We are often asked to deal with shower screens leaking along the wall or tray and cracked silicone between glass panels, on glass-to-frame joints, glass balustrade bases and glass-to-glass joints.
Much of London’s older housing was built with timber sash windows, some still in place and some long since replaced. Either way, the mastic between frame and brickwork is what stops draughts and rain getting in.
There’s a 12-month guarantee on every job, whatever its size.
- Location
- Northwood (HA6)
- Wider area
- Greater London
- Guarantee
- 12 months on all our work
- Quotes
- A clear quote up front
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
FAQs for Northwood
Can you do glazing silicone in Northwood?
Yes. We work across London and the South East, and Northwood is part of that. You can phone 0345 464 0079 or email us and let us know what needs doing.
Is parking a problem for a job in Northwood?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly.
What do you put in the joint?
It depends on the joint: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. Brands we use include Arbo and Everbuild.
Do you seal glass balustrade bases?
We can, if the base joint is sealed. Send us pictures and we’ll take a look when you call 0345 464 0079 or send us an email.
Can you work on commercial sites?
Yes. Commercial and hotel work is a large part of what we do. We can talk about working times when we quote.
Are you insured?
Yes. Mr Mastic is fully insured, with over 20 years’ experience in sealant work.
Will resealing stop my conservatory leaking?
In many cases, as long as sealant is the cause. We find where the water gets in first before any sealing.
Will the old sealant be removed?
Yes, always, and completely. New sealant will not bond properly to old, so any old material comes out before anything new goes in.
How we quote for glazing silicone
The quote reflects the job in front of us. We take into account:
- Any mould that needs treating
- The product the joint needs
- How much old sealant there is and how hard it is to remove
- Working hours on commercial sites
Combining jobs into one visit is usually more efficient than separate visits, so tell us about everything that needs sealing. We’ll send you a clear quote for the lot.
Asking for a quote
Before you ask for a quote, have a think about:
- Access, such as stairs, a lift or height
- Photos by email, if that is easy
- What’s wrong with the joints now
- The address or postcode of the job
Call for a quick quote, or email us if that is easier. Tell us about the joints that need doing and we’ll talk you through the work.
DIY sealant or a professional job?
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
Looking after it afterwards
Joint life depends on how it’s used and looked after. We suggest:
- Use gentle products around the joints
- Ventilate the conservatory to cut condensation
- Look over the glazing joints once a year
- Clear the conservatory gutters regularly
Don’t use blades or scrapers near the bead when you clean. A soft cloth or sponge is best.
Drips or damp near a glazing joint shouldn’t be ignored. It may be sealant, or something else and we’ll find out which.
Glazing silicone in Northwood: local notes
The South East is one of the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. With historic houses such as Headstone Manor (about 3.3 miles south-east) nearby, there’s older building stock in the area around Northwood as well as newer homes. Where a home is older, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic.
Letting a property close to Carpenders Park station? Then leaking glazing joints, shower screens or conservatory seals are worth sorting between tenancies. For site and facilities teams at buildings such as Frithwood Primary School, larger buildings have plenty of frames, and the mastic around each one ages.
Northwood is about 3 miles south-east of Rickmansworth, in Greater London. Homes, rented property, offices and hotels in Northwood is covered for glazing silicone, old or new, large or small. The work is guaranteed for a year. Our area takes in 764 places across Greater London. There’s also a page for London, about 16 miles away.
Here we cover the HA6 postcode area for glazing silicone. Whether your property is on Little Stream Close and Sandy Lodge Way or a nearby road, we can help. Other places close to Northwood include Eastbury (1 mile north-east), Moor Park (1 mile north-west), Batchworth Heath (1 mile west), Batchworth (2 miles north-west) and Holywell (2 miles north). Within a short drive, we also cover City of Westminster (14 miles south-east), Marylebone (14 miles south-east), Kensington (12 miles south-east), St Pancras (14 miles south-east), Hampstead (11 miles south-east) and Ruislip (3 miles south).
What’s near Northwood
In Northwood, that means homes and buildings near King George V Playing Fields, The Gate Public House and London School of Theology, among other places. Northwood’s nearest station is Carpenders Park station, about 1.7 miles north-east of the centre. Well-known places in the area include Harlequin Centre (2.9 miles north-east) and Heath Robinson Museum (2.2 miles south-east). Green spaces nearby include Dews Farm Sand Pits and Tumbling Bay.
What happens on the day
A visit follows a simple pattern: we look at the joints together, mask and protect the surrounding surfaces, do the work and tidy away. It normally takes a few hours, depending on how many joints need doing. For a job in Northwood, parking and access are the things to plan: let us know about parking, the floor we will be working on and any lift or shared entrance.
- First, we trace the leak and check it’s coming through a sealant joint.
- 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.
Before we arrive
- Mention any leaks or damp you’ve noticed
- For indoor joints, keep the area dry beforehand if you can
- Let us know about parking restrictions
Getting a quote
Getting a quote is simple: let us know the job and the location and its rough size. Photos by email help us understand the job.
Related advice
When to call us in Northwood
On shower screens, constant water and cleaning products wear silicone. Mould gets into it and the edges begin to peel.
The most common problems we see are:
- Conservatory leaks at frame and glazing joints
- Glass-to-glass joints that have split
- Black or yellowed silicone on glass joints
- Water tracking down the inner face of the glass
If you live in an older home near Emmanuel Church, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
What to look for in a quote
- What happens if they find a problem under the old sealant
- Which sealant they’ll use, and why
- Is VAT in the price?
- How the joint is cleaned and prepared
Landlord and commercial work in Northwood
For anyone letting property in or around Northwood, several properties can be quoted together. Just tell us the addresses and what each one needs, and photos by email help.
Mouldy or split sealant often shows up at the end of a tenancy. We can quote for more than one property at once.