Greater London · England
New Build Mastic in Northwick Park
Plot mastic for developers and snagging failed sealant in new homes in Northwick Park, with a one-year guarantee on every job. Call for a quick quote.
- Sealant that never bonded to the surface
- Shower seals failing in the first year or two
- Second-fix sealing on new plots
How the job changes by surface
Bathrooms and en suites
Baths, showers, basins and trays in new bathrooms are the most common new-build reseal. The old sealant comes out and anti-fungal sanitary silicone goes in after cleaning and priming.
Skirting and floors
Wet-area floor joints need a flexible seal. They get a flexible, water-resistant sealant.
New build mastic in Northwick Park, done properly
If your new home has a leaking shower seal, open skirting joints or untidy sealant, we can help. While the builder’s snagging or warranty period runs, report it to them first, and if it is not put right, get in touch with us. We work on skirting & floors, kitchens and show homes, and the jobs we see most are kitchen sealant that has pulled off the wall and cracks appearing as a new home settles.
Much of London’s new housing is flats in larger developments. Snagging there often goes through the developer or managing agent, and shower seals that fail early, skirting joints that open up and gaps at thresholds are all common snags.
A 12-month guarantee comes with the work, just as it does everywhere we cover.
- Where
- Northwick Park (HA1, HA3, HA0)
- Wider area
- Greater London
- Cover
- One year on every job
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Why it’s worth doing now in Northwick Park
A tube of sealant from the DIY shop won’t fix the cause: grit, unprimed surfaces and old layers underneath. 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 for homes in Northwick Park.
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote.
Why book with us
- Rated 4.9 stars on Google
- An ARBOMaster approved applicator
- We never seal over old sealant
- A sealant colour to suit the surroundings
Read our cost guide and customer reviews.
Also near Northwick Park
What else we do in Northwick Park
Signs you need new build mastic in Northwick Park
The first winter with the heating on dries a new home quickly. Gaps open along skirting, frames and worktops and cracked sealant shows up.
Any of these means the joints need attention:
- Skirting joints opening in the first winter
- New-build shower sealant that has already split
- Untidy sealant flagged on a snagging list
- Plot mastic for developers ahead of handover
As a London address, Northwick Park can be tricky for parking: let us know about parking bays, permits or a driveway.
Questions to ask before you book
- What guarantee comes with the work
- How the joint is cleaned and prepared
- Is the old sealant removed completely?
- What product goes in the joint
How we quote for new build mastic
You will get a clear quote before any work starts. It takes into account:
- When we can work, for business premises
- The product the joint needs
- The old material and how stubborn it is
- How many areas need sealing
Doing several joints on one visit generally makes better use of the time than several visits, so tell us about everything that needs sealing. You will get one clear quote for the whole job.
Helping us quote
To make quoting easier, let us know:
- Access, such as stairs, a lift or height
- Where the job is, and your postcode
- What the problem is, such as mould, gaps, leaks or cracking
- If it’s domestic, commercial or a hotel
For a quote, call 0345 464 0079 or send us an email and tell us where the job is and what the problem looks like. We will give you a clear price before any work starts.
Can I do it myself?
A DIY attempt does not rule out a professional job. We cut it out and start again, so tell us about it when you ask for a quote.
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
The process
At the end, we look at the finished work together and explain the cure time. The visit itself generally takes a few hours for most snagging lists, longer for a run of plots, depending on the size of the job. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. Mention any building rules, key holders or managing agents when you book.
- First we work through your snagging list or plot schedule with you.
- The old bead comes out in full, with no layer left behind.
- We clean off dust from the build and prime the surfaces where the product needs it.
- We apply a sealant that suits each joint and tool it to a neat finish.
- Each area is checked and left with its cure time.
Before we arrive
- Try not to wet indoor joints just before the visit
- Clear items away from the joints we’re working on
- Tell us if parking is tricky
How to get a quote
Want a quote for new build mastic? Please call 0345 464 0079 or send us an email and tell us about the job. You’ll know what we plan to do, and what it will cost, before any work begins.
Read more
Questions from Northwick Park
Do you cover Northwick Park for new build mastic?
Yes, Northwick Park is within the area we cover. Our work covers London and the South East. You can phone 0345 464 0079 or drop us an email and let us know what needs doing.
Do you work for landlords with property near Kenton station?
Yes. We work for landlords and letting agents as well as householders. Just ring 0345 464 0079 or email us with the address and what needs doing, and we’ll send you a clear quote.
Do you remove the old sealant?
Yes. Sealing over old sealant is the main reason resealing fails early, and it’s something we never do.
Do you take on second-fix sealing for builders?
Yes. Plot mastic and second-fix sealing for developers is part of our work. Send us the plot schedule and we’ll quote.
Is it worth resealing while the house is still settling?
Any seal that is leaking should be redone straight away. Cosmetic gaps can wait until the first year or two of movement has passed.
Do you work for hotels and businesses?
Yes. Commercial and hotel work is a large part of what we do. Working times can be discussed when we quote.
Will there be a smell?
It depends on the product. Some smell for a while, some hardly at all, and any smell fades as they cure.
Are you insured?
Yes. We’re fully insured, and we’ve been doing sealant work for more than 20 years.
Aftercare tips
No joint lasts for ever, but care makes a real difference. Our tips:
- Ventilate bathrooms well, especially in the first year
- Report sealant problems to your builder during the snagging period
- Avoid running a DIY bead over the old one
- Keep water off fresh sealant until it has cured
Keep photos of the joints and any snagging correspondence with your builder. It’s useful if you need to raise other issues later.
Mould takes hold quickly in sealant that has gaps or lifted edges. Dealing with it before it goes black keeps the job straightforward.
New build mastic around Northwick Park
Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Much of London’s new housing is flats in larger developments, where snagging may go through the developer or managing agent.
If you’ve bought a new home near Kenton station, the sealant around baths, showers and frames is worth checking in the first year or two.
Northwick Park is about 1 mile south-west of Kenton, in Greater London. Northwick Park gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. We cover 764 towns and villages across Greater London. You can also see our page for London, roughly 11 miles from Northwick Park.
Every address in HA1, HA3 and HA0 is within our area for new build mastic. You will find streets such as Lyon Road, Manor Road and Gayton Road, all of which we cover. Main roads around Northwick Park include the A404. Close by, we work in Greenhill (1 mile north-west), Harrow on the Hill (1 mile south-west), South Kenton (1 mile east), Kenton (1 mile north-east) and Harrow (1 mile west). Within a short drive, we also cover London (11 miles south-east), City of Westminster (9 miles south-east), Marylebone (9 miles south-east), Kensington (7 miles south-east), St Pancras (10 miles east) and Shoreditch (11 miles east).
Landmarks near Northwick Park
Around Northwick Park, our work takes us to homes and buildings near St Anselm's Catholic Primary School, Orley Farm School and Preston Park, among other places. For rail, the closest station is Kenton station, about 0.6 miles north-east of the centre. Well-known places in the area include Northwick Park Hospital (under half a mile north-east) and Kodak Museum (1.5 miles north-west). Open spaces near Northwick Park include Masons Field and Northala Fields.