Greater London · England
New Build Mastic in Longlands
Professional new build mastic in and around Longlands, with old sealant always removed completely and a 12-month guarantee.
- Untidy sealant flagged on a snagging list
- Leaking shower tray seals in a new home
- Frame joints opening as the plaster dries
New build mastic for homes and businesses in Longlands
Some owners wait for the first year’s movement before having joints redone. That makes sense for small gaps that are just cosmetic, but a failed shower or bath seal shouldn’t wait. We are often asked to deal with gaps between new skirting and floors and untidy sealant flagged on a snagging list, on kitchens, skirting & floors and windows & doors.
Across London, commercial floors have movement joints that break down under heavy foot traffic, and new homes need their plot mastic finished properly before handover.
You’re covered for a year from the day we finish. If there’s a problem with it, please phone 0345 464 0079 or drop us an email.
- Location
- Longlands (DA15, DA14, SE9)
- Region
- Greater London
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Different surfaces, different methods
Windows and doors
External mastic around new windows and doors is sometimes rushed or missed. It’s resealed with an exterior sealant suited to the frame and wall.
Bathrooms and en suites
New-build bathrooms and en suites are where sealant fails most often. We cut out the failed bead, clean and prime, and reseal with anti-fungal sanitary silicone.
How to look after the new joints
A little care helps the new joints last. Our advice:
- Don’t wait for the house to settle if water is getting through
- Ventilate bathrooms well, especially in the first year
- Check bath and shower seals every few months as the house settles
- Don’t seal over failed sealant yourself
Keep the bathroom ventilated, especially in the first year. Use the extractor fan or open a window after showers so moisture doesn’t sit on the sealant.
The sooner you deal with untidy or cracking sealant, the less there is to put right. Left alone, a small crack can become a leak over time.
DIY versus a professional finish
If you do try it yourself, take your time over the 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 heavy bead looks messy and copes badly with movement, and the joint depth matters as much as the finish.
When it is not the sealant
In fairness, some problems need a different trade:
- Deciding who is responsible under a builder’s warranty
- Plumbing faults behind the sealant
- A tray or bath that isn’t properly supported, until it’s fixed
If in doubt, phone 0345 464 0079 or email us and we will say what we think before booking.
Where we work in Longlands
- Kitchens
- Skirting & floors
- Bathrooms & en suites
- Show homes
- Plot handovers
- Windows & doors
New homes and floors in Longlands
Many of London’s new homes are flats in bigger developments, where snagging may go through the developer or managing agent. 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.
Longlands is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Longlands is about 1 mile west of Sidcup, in Greater London. Across the DA15 area, our applicators can take on new build mastic. Across Greater London, we cover 764 places, Longlands among them. We also work in London, around 9 miles away.
Jobs for new build mastic in DA15, DA14 and SE9 is quoted and booked the same way as anywhere else. Local streets include Main Road, Alder Road and Sidcup Road, all of which we cover. Longlands is on the A211, which makes it straightforward to reach. Close by, we work in Foxbury (1 mile south), New Eltham (1 mile north-west), Chislehurst (1 mile south-west), Coldharbour (1 mile west) and Blackfen (1 mile north). We also work in nearby towns such as London (9 miles north-west), City of Westminster (12 miles north-west), Marylebone (12 miles north-west), Kensington (13 miles west), St Pancras (11 miles north-west) and Shoreditch (10 miles north-west).
Local landmarks in Longlands
In Longlands, that means homes and buildings near Waring Park, Chislehurst School for Girls and Ye Olde Black Horse Inn, among other places. The nearest railway station is New Eltham station, roughly 0.8 miles north-west. A little further out are Queen Mary's Hospital (1 mile south-east) and Greenwich Castle (5 miles north-west). The countryside around Longlands includes Summer Hill and The Tarn.
What we’re called out for in Longlands
Later trades and the final clean can damage fresh sealant. If it’s disturbed before curing, the joint can be left weak and it shows once the home is in use.
It’s worth asking for a quote if you see:
- Cracked caulk along new skirting
- Cracked sealant around new window and door frames
- Leaking shower tray seals in a new home
- Kitchen sealant that has pulled off the wall
If you’ve bought a new home near New Eltham station, the sealant around baths, showers and frames is worth checking in the first year or two.
What your quote should include
- What guarantee comes with the work
- How much experience the applicator has
- Is the old sealant removed completely?
- Whether they’re fully insured
Questions from Longlands
Do you work for landlords with property near New Eltham station?
Yes, landlords and agents are among the people we work for. You can call 0345 464 0079 or drop us an email with the details for a clear quote.
Can parking be tricky for a visit in Longlands?
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.
What sealant do you use?
Products from Arbo and Everbuild, among others, chosen to suit the joint. We will tell you what we’re using and why.
Can you do plot mastic on a new development?
Yes. We take on second-fix sealant work across new plots. We clean and prime joints properly to keep callbacks down.
Can you do several jobs on one visit?
Yes. More than one area can be quoted together.
Does someone need to be in?
We need access to the joints, so we will agree that with you when we book. Indoors, that generally means someone at home.
Do you come to Longlands?
Yes. We’re based in Crawley and work across South East England, London and Scotland, Longlands included.
What colour sealant will you use?
Most bathroom joints are white or clear, but other colours are available. We match the colour to the finish.
Why deal with it now?
Water getting past a failed seal in a new build reaches walls and floors that are still settling. Resealing promptly protects the new finishes around it. Damp from a failed joint spreads quietly in older London brickwork and timber, and once it shows in Longlands, the repair is bigger than a sealant job.
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, along with when we can work on site. Call for a quick quote and we will explain what it covers.
Why book with us
- ARBOMaster approved applicator
- Full insurance on every job
- Any old sealant cut out fully, not covered over
- Neat joints and a tidy finish
Read what affects the cost and our reviews.
Also near Longlands
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The process
All our tools and materials come with us in the van, so there’s nothing for you to buy. Once we’ve agreed what’s being done, the area is protected and the work begins. Most jobs take a few hours in a single home. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Longlands. A visitor permit or a nearby bay makes the visit run more smoothly.
- We look at why each joint failed, including any movement.
- Old sealant is cut out and the joints cleaned.
- We make sure the joints are dry and prime them if needed.
- Baths are filled with water, then the new sealant is applied.
- We check every joint and leave you with the cure times.
Preparing for the visit
- Let us know about stairs, lifts or work at height
- Clear items away from the joints we are working on
- Keep pets and children clear of the area while we work
Get a quote
Want a quote for new build mastic? Please phone 0345 464 0079 or drop us an email with a few details. You will know what we plan to do, and what it will cost, before any work begins.