Greater London · England
Window & door mastic in Southgate, Greater London
Problem with your window and door frames in Southgate? We cut out the old, prepare the joints and apply the right sealant.
- Black, perished sealant on frames
- Draughty joints inside around the window
- White mastic on grey or black frames
Work for landlords, hotels and businesses
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance.
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
Window mastic in Southgate, done properly
Every window and door frame has a gap around it, and mastic is what closes it. When it cracks, hardens or pulls away, draughts and rain get in. Our applicators cut it out and replace it with a flexible, weatherproof sealant. We work on timber windows & doors, window sills and patio & French doors, and common reasons people get in touch are cracked or shrunken mastic around the frame and sealant in the wrong colour for the frame.
Many London homes are flats, with windows high above the street. Who looks after the outside of the frames can depend on the lease, so check that first.
There’s a 12-month guarantee on every job.
- Where
- Southgate (N14, N11, N21, N13)
- Region
- Greater London
- Cover
- 12 months on all our work
- Quote
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Your questions about window mastic in Southgate
Do you cover Southgate for window mastic?
Yes. Our work covers London and the South East, and Southgate is part of that. Just phone 0345 464 0079 or email us with a few details of the job.
Is parking an issue for window mastic in Southgate?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly, so mention what’s available when you book.
How long will my window job take?
Allow anything from an hour or two to a full day, depending on how many frames there are. Access and the amount of old mastic make the biggest difference.
Do you hold any approvals?
Yes. Mr Mastic is an ARBOMaster approved applicator and we are fully insured too.
Can you seal over the old sealant?
No. New silicone will not bond to old silicone, and it traps any mould or water underneath. We remove it all first.
Are you fully insured?
Yes. We’re fully insured for every job we do.
What sealant do you use?
Quality sealants from brands including Arbo and Everbuild, chosen to suit the joint. We’ll tell you what we are using and why.
Do I have to be there?
We need access to the joints, so we’ll agree that with you when we book. Indoors, that normally means someone at home.
Window mastic in Southgate: local notes
With historic houses such as Bruce Castle (about 3.2 miles south-east) nearby, there’s older building stock in the area around Southgate as well as newer homes. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. Rainfall in the South East is lower than in much of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Managing a site like Ashmole Primary School? Then the mastic around its windows and doors needs looking after like any other building’s. Southgate is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Southgate is about 3 miles south-east of Barnet, in Greater London. For window mastic in and around Southgate, it’s easy to get a quote: please call 0345 464 0079 or send us an email. We cover Greater London from our Crawley base, Southgate included. Southgate is one of 764 places in Greater London we cover. London is on our list too, about 9 miles from Southgate.
Our applicators cover all of the N14, N11, N21 and N13 postcode area for window mastic and the streets around it. That includes homes and businesses on High Street, Station Road and Blagden's Close and the roads around them. Southgate sits on or near the A111 and A1004, so getting to you is simple. We also cover the places around Southgate: Osidge (1 mile north-west), Brunswick Park (1 mile west), Arnos Grove (1 mile south), New Southgate (1 mile south) and Oakwood (1 mile north). Further out, we also cover London (9 miles south), City of Westminster (8 miles south), Marylebone (8 miles south), Kensington (9 miles south), St Pancras (7 miles south) and Shoreditch (7 miles south).
Near you in Southgate
Typical jobs here are in homes near The New Crown pub, Grovelands Park and Ashmole Academy. The nearest railway station is New Southgate station, about 1 mile south-west of the centre. Other landmarks nearby include Grand Arcade (2.1 miles south-west) and Greentrees Hospital (1.9 miles south-east). Open spaces near Southgate include Highgate Hill and Barfield Allotments Nature Park.
What the job involves on each surface
Timber windows & doors
On period timber windows, traditional sand mastic is sometimes the better choice. We will tell you which suits your home.
Window sills
Where a sill meets brick or render, the ends often crack first. We reseal them so rain can’t run into the wall.
How we quote for window mastic
Every job gets its own quote. These are the things that affect it:
- Whether the work is at height
- Whether old sealant or filler has to be cut out
- How many areas need sealing
- Any working-time requirements on site
Leaving a failed joint normally makes the job bigger, not smaller, as water and mould keep getting in. If you are unsure, phone 0345 464 0079 or email us and we will give you an honest view and a quote.
Helping us quote
A few details help us give you an accurate quote. When you get in contact, it helps to mention:
- If someone has resealed it before
- Pictures of the joints, sent by email
- Where the property is
- How many joints, rooms or windows are involved
We don’t publish a price list, as no two jobs are quite the same. Instead, we give you a clear price for your job. To arrange one, ring 0345 464 0079 or email us.
Keeping the joints in good condition
A little care helps the new joints last. Our advice:
- Clear any debris from frame drain holes
- Keep timber frames painted
- Avoid blasting the frames with a pressure washer
- Use gentle cleaners on frames and sealant
Wipe the frames with soapy water when you clean the windows, and keep solvents and harsh chemicals off the joint.
Wet, windy weather is when failed mastic shows itself, but resealing works best in dry conditions. Dealing with it when you first notice a crack avoids chasing leaks through the wet months.
Signs you need window mastic in Southgate
Every frame moves through the day. Sun on a frame makes it expand, and it contracts again overnight, while the brick or render around it hardly moves. If the sealant can’t stretch, it splits.
It’s worth asking for a quote if you see:
- Water coming in at the bottom corners of a door
- Draughty joints inside around the window
- Mastic that has split away from the wall
- White mastic on grey or black frames
In the older streets around Christ Church Southgate Parish Church, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
What your quote should include
- Which colour the sealant will be
- The length of the guarantee
- What happens if they find a problem under the old sealant
- Whether they seal over old material or remove it
Also near Southgate
More services for Southgate
How it works
All our tools and materials come with us in the van, so you do not need to buy or prepare anything. Once we have agreed what’s being done, the area is protected and the work begins. It normally takes anything from an hour or two to a full day, depending on how many frames there are. In Southgate, flats, stairs and shared entrances are part of the routine. Mention any building rules, key holders or managing agents when you book.
- First, we go round the frames with you and agree the list.
- The old mastic is cut out and scraped back to clean surfaces.
- Deep gaps get closed-cell backing rod to set the depth.
- A flexible exterior sealant is applied in a colour to suit the frame.
- We tool each bead neatly and check every joint is closed.
Getting ready for the visit
- Where the joints are inside, avoid wetting them before we arrive
- Plan for the work area to be out of bounds to pets and children
- Mention any tricky access
Get a quote
For a quick quote, get us on the phone, or send an email if you’d rather. Describe what needs sealing and we’ll talk you through the work before giving you a price.
Related advice
DIY versus a professional finish
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.
If you’re set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.