Greater London · England
Walworth New Build Mastic
New build mastic across Walworth and nearby, with every bit of old sealant taken out first and a 12-month guarantee.
- Sealant applied over dusty or wet surfaces
- Second-fix sealing on new plots
- Messy sealant that spoils new finishes
Looking after it afterwards
Looking after new joints is easy:
- Put sealant faults on your snagging list early
- Follow the cure time we give you
- Photograph failed sealant before it’s redone
- Ventilate bathrooms well, especially in the first year
Keep photos of the joints and any snagging correspondence with your builder. It’s useful if you need to raise other issues later.
A failed seal in a new home lets water into joists, plasterboard and ceilings. Early resealing keeps the job small and protects the rest of the house.
New build mastic for homes and businesses in Walworth
Some owners wait for the first year’s movement before having joints redone. For small cosmetic gaps, that’s reasonable, but a failed shower or bath seal shouldn’t wait. If you are dealing with cracked sealant around new window and door frames and gaps opening as the house dries out and settles, we can put it right, on plot handovers, bathrooms & en suites and show homes alike.
Shops, offices and commercial units across London have hard-wearing floors with movement joints that need resealing as they wear, and new homes need their plot mastic finished properly before handover, in Walworth and beyond.
We guarantee the work for a year. If there’s a problem with our work within the year, let us know and we will sort it.
- Where
- Walworth (SE1P, SE17, SE1)
- Region
- Greater London
- Cover
- A year, on every job
- Price
- A clear price before work begins
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
How we quote for new build mastic
The price is agreed before any work begins. It’s based on:
- The amount of work
- Any mould that needs treating
- Working hours on commercial sites
- How many areas need sealing
Homes and businesses are quoted the same way: how much there is to do, how we reach it and what it needs. Call for a quick quote and we will explain what it covers.
Helping us quote
There’s no need for technical detail. It helps if you can tell us:
- The type of property
- Where the property is
- The rough size of the job
- How we’d reach the joints
There’s no standard price list. Instead, we give you a clear price for your job. To arrange one, phone 0345 464 0079 or drop us an email.
What the job involves on each surface
Bathrooms and en suites
En suite seals are easy to miss on a snagging list until they leak. A proper reseal keeps water in the tray.
Show homes
In a show home, the sealant is on display. We lay neat, even beads in colours to suit the finishes.
Towns and villages near Walworth
Also in Walworth
New build mastic around Walworth
Much of London’s new housing is flats in larger developments, where snagging may go through the developer or managing agent. The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Walworth is in London, so parking needs planning: let us know about parking bays, permits or a driveway. If you’ve bought a new home near Elephant & Castle station, the sealant around baths, showers and frames is worth checking in the first year or two.
Walworth is about 1 mile south of London, in Greater London. Walworth gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. Walworth is one of 764 towns and villages in Greater London where we work.
Jobs for new build mastic in SE1P, SE17 and SE1 is quoted and booked the same way as anywhere else. We cover properties on Mina Road, Ash Avenue and Angel Lane and the roads around them. We also cover the places around Walworth: London (1 mile north), Bermondsey (1 mile north-east), Camberwell (1 mile south), South Bermondsey (1 mile east) and Denmark Hill (2 miles south). Within a short drive, we also cover City of Westminster (3 miles north-west), Marylebone (3 miles north-west), Kensington (5 miles west), St Pancras (3 miles north-west), Shoreditch (3 miles north) and Walthamstow (7 miles north-east).
Around Walworth
Typical jobs here are in homes near University Academy of Engineering South Bank, Nursery Row Park and Lord Nelson pub. Nearby too are Lambeth Palace Library (1.3 miles north-west) and St Saviour's and St Olave's Church of England School (less than half a mile north). The nearest railway station is Elephant & Castle station, about 0.5 miles north-west. Nearby you’ll also find Gabriel's Wharf (1.5 miles north-west) and The Walworth Clinic (less than half a mile west). Green spaces nearby include Bellenden Road Nature Garden and St. James's Park Lake.
DIY sealant or a professional job?
If you’ve already had a go yourself, that’s fine. We cut it out and start again.
The biggest DIY mistake is sealing over old sealant. New silicone won’t bond to old, so it peels away and traps moisture behind it. All the old material has to come out first.
Why deal with it now?
Running a new bead over the builder’s sealant might look tidy for a few weeks, but it can’t bond to what’s underneath. A lasting seal starts with removing the old one completely. In London conversions, one flat’s bathroom is often above another flat’s ceiling, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler.
A failed joint rarely gets cheaper to fix by waiting. If you are unsure, phone 0345 464 0079 or email us for an honest opinion and a quote.
Why choose Mr Mastic in Walworth
- Domestic, commercial and hotel work
- Over 20 years’ experience
- An ARBOMaster approved applicator
- 4.9 on Google from 180+ five-star reviews
See our cost guide and our reviews.
The process
Every visit runs the same way: we look at the joints together, protect the area around them, do the work and tidy away. Most jobs take a few hours for most snagging lists, longer for a run of plots. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Walworth. It helps if you can point us to a visitor permit or a bay close to the door.
- We go through the snagging list or plot schedule and agree the joints to do.
- We cut out every bit of the failed or messy sealant.
- We clean off dust from the build and prime the surfaces where the product needs it.
- A sealant chosen for each area goes in and is tooled smooth.
- Finally, each room is checked and you are given the cure time.
How to prepare
- Let us know if you’ve seen damp or leaks
- Try not to wet indoor joints just before the visit
- Mention if the joints have been sealed before
How to get a quote
Need a quote? Please call 0345 464 0079 or email us with a few details. We’ll explain what we’d do and give you a clear price before any work starts.
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Questions from Walworth
Can you help a landlord with a rental near Elephant & Castle station?
Yes, we work for landlords and letting agents. You can ring 0345 464 0079 or send us an email with the address and a few details, and we will give you a fixed price before any work starts.
Do you cover Walworth for new build mastic?
Yes. We work across London and the South East, and Walworth is part of that. Just call 0345 464 0079 or drop us an email with a few details of the job.
My new home is still under warranty. Should I contact you?
If you are still within the builder’s snagging or warranty period, report it to them first. If they’re slow or the fix does not last, we can help.
Can I send you my snagging list?
Yes. Photos of each sealant item help us quote. If something isn’t sealant, we will say so.
Is the work guaranteed?
Yes: twelve months. If anything is not right with the work within the year, let us know and we will sort it.
What information do you need?
Tell us what needs doing and where. We will ask anything else we need to know.
Can you work on commercial sites?
Yes, regularly. We can plan bigger jobs in stages.
How long will you be here?
It depends on the size of the job, but as a guide it takes a few hours for most snagging lists, longer for a run of plots. We’ll tell you when we quote.
When something else is needed
We’ll always be straight with you, so here’s what sealant can’t fix:
- Leaks from pipes, valves or wastes, which need a plumber
- Baths and trays that move too much for sealant to cope with
- Disputes or warranty claims with your builder
If you are not sure, just ring 0345 464 0079 or send us an email and we will give you a straight answer.
Joints and surfaces we work on
- Show homes
- Skirting & floors
- Plot handovers
- Windows & doors
- Bathrooms & en suites
- Kitchens