Greater London · England
New Build Mastic in Knightsbridge
New build mastic across Knightsbridge and nearby, with every bit of old sealant taken out first and a 12-month guarantee.
- Shower seals failing in the first year or two
- Messy sealant that spoils new finishes
- Sealant applied over dusty or wet surfaces
Signs you need new build mastic in Knightsbridge
The wrong product is sometimes used in the wrong place: caulk where water collects, or a rigid product on a moving joint. Neither lasts long.
The problems people normally mention when they call include:
- Messy sealant that spoils new finishes
- Second-fix sealing on new plots
- New-build shower sealant that has already split
- Gaps behind new kitchen upstands
Knightsbridge is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Comparing quotes
- Whether you can choose the colour
- What preparation is included
- Is the old sealant removed completely?
- Who turns up on the day
New build mastic in Knightsbridge
We never seal over a failed new-build bead. Fresh silicone can’t bond to the old layer, so it all comes out before we clean, dry and reseal. If you have cracked caulk along new skirting and smeared, uneven beads picked up at snagging, we can help, on kitchens, windows & doors and skirting & floors 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 Knightsbridge and beyond.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we’ll put it right.
- Where
- Knightsbridge (SW1X, SW3, W1K)
- Region
- Greater London
- Guarantee
- A year, on every job
- Quote
- A clear price before work begins
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
For landlords and businesses
We regularly work with letting and managing agents. Tell us the address, the job and how access works and we’ll quote.
Hotels need rooms back in use, 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.
DIY sealant or a professional job?
If you’re set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it doesn’t work out, we can still put it right.
If you’ve already had a go yourself, that’s fine. We remove it and do the joint properly.
When something else is needed
We won’t take on work that won’t last, so these are the limits:
- A tray or bath that isn’t properly supported, until it’s fixed
- Cracked trays, tiles or worktops
- Leaks from pipes, valves or wastes, which need a plumber
If in doubt, call 0345 464 0079 or send us an email and we’ll say what we think before booking.
Joints and surfaces we work on
- Skirting & floors
- Plot handovers
- Bathrooms & en suites
- Show homes
- Kitchens
- Windows & doors
What new build mastic looks like in Knightsbridge
Compared with the north and west, the South East gets less rain, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. Many of London’s new homes are flats in bigger developments, where snags may need reporting through the developer or the managing agent.
If you’ve bought a new home near London Victoria station, the sealant around baths, showers and frames is worth checking in the first year or two.
Knightsbridge is about 1 mile north of Brompton, in Greater London. If you need new build mastic in Knightsbridge, please phone 0345 464 0079 or send us an email for a quick quote. We cover Greater London from our Crawley base. 764 places in Greater London are on our list, from the larger towns to small villages.
Every address in SW1X, SW3 and W1K is covered for new build mastic, from the main roads to the quietest streets. That includes homes and businesses on Hans Road, Park Lane and Cadogan Lane and the roads around them. Knightsbridge sits on or near the A315 and A4202, so getting to you is simple. Neighbouring places we cover for new build mastic include Tyburn (1 mile north), Mayfair (1 mile north-east), Hyde Park Estate (1 mile north), Connaught Village (1 mile north) and City of Westminster (1 mile north-east). Further out, we also cover London (3 miles east), St Pancras (3 miles north-east), Shoreditch (4 miles north-east), Walthamstow (8 miles north-east), Hoxton (4 miles north-east) and Whitechapel (4 miles east).
Near you in Knightsbridge
Around Knightsbridge, our work takes us to homes and buildings near Saint Thomas More Language College, St Joseph's Catholic Primary School and Paxtons Head pub. Also close by are Natural History Museum Library and Archives (0.7 miles south-west) and Royal Parks of London (0.5 miles north). The closest station to Knightsbridge is London Victoria station, roughly 0.9 miles south-east. A little further out are London Lock Hospital (0.6 miles east) and Westminster Synagogue Czech Memorial Scrolls Museum (less than half a mile west). Open spaces near Knightsbridge include Campden Hill and Greville Place nature reserve.
Also near Knightsbridge
Also in Knightsbridge
Knightsbridge: your questions answered
Can parking be tricky for a visit in Knightsbridge?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. That way the visit can be planned around it.
Do you work for landlords with property near London Victoria station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
How long does the job take?
Most jobs take a few hours for most snagging lists, longer for a run of plots, including preparation and clearing up. We will confirm how long when we quote.
Where is Mr Mastic based?
Our base is Crawley. We work across South East England, London and Scotland.
Will you leave a mess?
Very little: the area around the joints is protected first, and we tidy up before we go.
Why has my new-build shower seal failed already?
Lots of new homes see sealant crack early as timber and plaster dry out. Poor preparation at handover adds to it.
Will you just run a new bead over the existing one?
No. Over-sealing traps mould and water and soon fails. All the old sealant comes out before any work starts.
Can you do several jobs on one visit?
Yes. More than one area can be quoted together.
Leave it or put it right?
For developers, getting the sealant right first time saves return visits. Snagging visits for failed sealant cost time on every plot, and they’re avoidable with good preparation. In a London flat, a failed joint rarely stays your problem alone: water can reach the neighbours below, and gaps in fire-rated joints affect the whole building.
Combining jobs into one visit usually makes better use of the time than several visits, so tell us about everything that needs sealing. You’ll get one clear quote for the whole job.
Why Knightsbridge customers choose us
- A choice of colours where the product allows
- Rated 4.9 stars on Google
- ARBOMaster approved applicator
- Old sealant always removed completely
How the visit works
There isn’t much for you to do on the day. Show us the job and we will take it from there. The work itself takes a few hours for most snagging lists, longer for a run of plots, including the tidy-up. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Knightsbridge. A visitor permit or a nearby bay makes the visit run more smoothly.
- Each joint is checked for movement before we start.
- We remove the failed sealant and clean the joints.
- We make sure the joints are dry and prime them if needed.
- New sealant goes in, with baths filled first so they’re at their heaviest.
- The finished joints are checked and the cure times given.
How to prepare
- Clear items away from the joints we’re working on
- Mention any sign-in or site rules at work premises
- Let us know about parking restrictions
Getting a quote
Need a quote? Please call 0345 464 0079 or drop us an email and tell us about the job. We will explain what we’d do and send you a clear quote before any work starts.
Related advice
Keeping the joints in good condition
A little care helps the new joints last. Our advice:
- Use the extractor fan every time you shower
- Get a leaking seal dealt with right away
- Photograph failed sealant before it’s redone
- Put sealant faults on your snagging list early
Ventilation matters in a new home, which is still drying out. Use the extractor fan or open a window after showers so moisture does not sit on the sealant.
If a shower tray or bath seal splits in the first year, look for movement. Have it resealed, and the tray or bath checked, before it gets worse.