Greater London · England
New-build mastic & snagging in New Southgate, Greater London
New build mastic across New Southgate and nearby, with every bit of old sealant taken out first and a 12-month guarantee.
- Internal frame sealant that has split
- Second-fix sealing on new plots
- Messy sealant that spoils new finishes
About our new build mastic in New Southgate
Snagging sealant properly means taking the failed bead out completely. Fresh silicone cannot bond to the old layer, so it all comes out before we clean, dry and reseal. If you are dealing with skirting joints opening in the first winter and shower seals failing in the first year or two, we can put it right.
New flats are going up across London, many of them in larger developments. Snagging there often goes through the developer or managing agent, and failed shower seals, open skirting joints and gaps at thresholds are typical.
A one-year guarantee comes as standard, so you’re covered after we’ve gone.
- Place
- New Southgate (N11, N10, N14)
- Wider area
- Greater London
- Guarantee
- 12 months on all our work
- Quotes
- A clear quote up front
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
New build mastic around New Southgate
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. Much of London’s new housing is flats in larger developments, where snags may need reporting through the developer or the managing agent.
As a London address, New Southgate can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
New Southgate is about 2 miles north-east of Finchley, in Greater London. Jobs in New Southgate get the same care as everywhere else we work: old sealant removed completely, careful preparation and a one-year guarantee. New Southgate is one of 764 towns and villages in Greater London we cover. Our London page covers work nearby, about 8 miles away.
We work across the N11, N10 and N14 postcode area for new build mastic. You’ll find streets such as High Road, Orion Road and Atlas Road, all of which we cover. With the A1003 and A1110 close by, New Southgate is simple for us to get to for new build mastic. Other places close to New Southgate include Friern Barnet (1 mile west), Arnos Grove (1 mile east), Bounds Green (1 mile south-east), Brunswick Park (1 mile north) and Southgate (1 mile north). We also work in nearby towns such as London (8 miles south), City of Westminster (7 miles south), Marylebone (7 miles south), Kensington (8 miles south), St Pancras (6 miles south) and Shoreditch (7 miles south-east).
Near you in New Southgate
In New Southgate, that means homes and buildings near Friern Barnet School, Ming-Ai and The Ranelagh pub. Other local landmarks include O. R. Tambo Recreation Ground (0.9 miles south-east) and Francis Skaryna Belarusian Library and Museum (1.8 miles west). New Southgate has its own railway station: New Southgate station. A little further out are Grand Arcade (1.5 miles west) and Broomfield House Museum (1.1 miles east). For a walk, there’s Barfield Allotments Nature Park and Highgate Hill.
Also near New Southgate
Other services in New Southgate
Signs you need new build mastic in New Southgate
Baths and trays settle under load once the home is lived in. If a bath wasn’t filled when it was sealed, the bead is stretched the first time it’s used.
These are the problems we are asked about most:
- Cracks appearing as a new home settles
- New-build shower sealant that has already split
- Worktop and upstand sealant coming away
- Frame joints opening as the plaster dries
For new homes near New Southgate station, it’s worth checking the sealant early, while snags are still fresh.
Comparing quotes
- How the colour is chosen
- Whether all the old sealant comes out first
- Whether VAT is included
- How long to leave it before use
How it works
All our tools and materials come with us in the van. Once we have agreed what’s being done, the area is protected and the work begins. It normally takes a few hours in a single home. In New Southgate, as in most of London, parking needs a little planning. A visitor permit or a nearby bay makes the visit run more smoothly.
- We start by going through the snagging items or plot schedule with you.
- Every bit of the old builder’s sealant is cut out down to clean surfaces.
- We clean out the dust and grit left from the build.
- Primer goes on where the surface and product need it, then the new sealant.
- We tool every joint neatly and tell you when each area can be used.
How to prepare
- For business premises, tell us about site rules or sign-in
- Try not to wet indoor joints just before the visit
- Mention any parking rules near the property
Get a quote
Want a quote for new build mastic? Please call 0345 464 0079 or send us an email with a few details. You will know what we plan to do, and what it will cost, before any work begins.
Read more
For landlords and businesses
Letting agents often deal with us directly. Tell us the address, the job and how access works and we will give you a quote.
For anyone letting property in or around New Southgate, jobs at different addresses can go on one quote. Just tell us the addresses and what each one needs.
Different surfaces, different methods
Show homes
In a show home, the sealant is on display. We lay neat, even beads in colours to suit the finishes.
Skirting and floors
New homes often develop a gap between skirting and floor. We seal it with a flexible sealant that copes with the movement.
Why act early in New Southgate
A tube of sealant from the DIY shop won’t fix the cause: dust, no primer and old sealant left in the joint. Proper removal and preparation are what make it last. Converted houses in London often have a bathroom above someone else’s living room, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Putting it right early is much less trouble.
A failed joint rarely gets cheaper to fix by waiting. If you are unsure, ring 0345 464 0079 or email us for an honest opinion and a quote.
What you get with us
- Rated 4.9 stars on Google
- Homes, businesses and hotels
- Tidy, careful work
- Any old sealant cut out fully, not covered over
See our cost guide and what customers say.
Your questions about new build mastic in New Southgate
Is parking a problem for a job in New Southgate?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. That way the visit can be planned around it.
Can you help a landlord with a rental near New Southgate station?
Yes, rental work is part of what we do. You can ring 0345 464 0079 or email us with the address and a few details, and we will give you a fixed price before work begins.
What should I tell you?
Where the job is, what the problem is and roughly how big it is. If you can, email a few photos.
Can you work on commercial sites?
Yes. We can plan bigger jobs in stages.
Are you insured?
Yes. Mr Mastic is fully insured, with over 20 years’ experience in sealant work.
What do you put in the joint?
We choose the sealant for the joint, not the other way round. Movement, water and weather all affect the choice, and we will tell you what we’re using.
Should I try DIY first?
You can, for simple jobs. Preparation is everything: all the old sealant out, and a clean, dry joint. If it does not work out, we can redo it.
Can you do several jobs on one visit?
Yes. Tell us about everything you’d like done and we will quote it together.
DIY sealant or a professional job?
If you do try it yourself, take your time over the 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.
If you’ve already had a go yourself, that is fine. We remove it and do the joint properly.
How we quote for new build mastic
Your quote is based on your job. We take into account:
- Mould in or behind the old joints
- Any working-time requirements on site
- How much there is to do
- The product the joint needs
A few things move the cost up or down: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether the work is at height. Your quote takes all of that into account.
Helping us quote
Before you ask for a quote, have a think about:
- The rough size of the job
- The type of property
- Access, such as stairs, a lift or height
- Whether it has been sealed before
The more we know about the job, the more useful the quote. Tell us where the job is, what’s wrong and how much there is.