West Sussex · England
Keymer New Build Mastic
Plot mastic for developers and snagging failed sealant in new homes for Keymer, backed by a one-year guarantee. Call for a quick quote.
- Skirting joints opening in the first winter
- Frame joints opening as the plaster dries
- Smeared, uneven beads picked up at snagging
New build mastic in Keymer
Some new-home owners let the house settle before resealing. 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 smeared, uneven beads picked up at snagging and sealant that never bonded to the surface, on skirting & floors, plot handovers and kitchens.
In and around Keymer, floors range from older timber boards to tiles and newer finishes, each moving in its own way. Skirting and threshold joints need a sealant that suits the floor.
Our work is backed for twelve months, in Keymer and everywhere else we cover.
- Place
- Keymer (BN6)
- Region
- West Sussex
- Guarantee
- 12 months on all our work
- Price
- A clear price before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Do you need new build mastic in Keymer?
When the heating goes on in the first winter, the house dries fast. Gaps open along skirting, frames and worktops.
Common reasons people contact us include:
- Cracked caulk along new skirting
- Messy sealant that spoils new finishes
- New-build shower sealant that has already split
- Kitchen sealant that has pulled off the wall
For new homes near Hassocks station, it’s worth checking the sealant early, while snags are still fresh.
Questions to ask before booking
- How the colour is chosen
- How hidden problems are handled
- What insurance they hold
- Is VAT in the price?
Keymer questions
I let a flat near Hassocks station. Can you help?
Yes, we work for letting agents and landlords. Just ring 0345 464 0079 or send us an email and tell us about the property, and we’ll give you a clear quote.
Is Keymer in your area for new build mastic?
Yes. Our work covers London and the South East, and Keymer is part of that. You can call 0345 464 0079 or send us an email and tell us what needs doing.
Where are you based?
Our base is Crawley, with over 20 years’ experience. Our area covers South East England, London and Scotland.
Is there any odour?
That depends on the sealant. Some products have a noticeable smell, others very little, and any smell fades as they cure.
What information do you need?
The location, the problem and the rough size of the job. If you can, email a few pictures.
Will you leave a mess?
No. We work neatly, protect the area around the joints and tidy up afterwards.
How long should I leave it?
Many sealants skin over quickly but take longer to cure fully. We’ll tell you how long to leave the joint before we leave.
Is it worth resealing while the house is still settling?
That depends on the joint. A leaking shower or bath seal should be redone straight away, but cosmetic gaps can wait for movement to slow.
New build mastic in Keymer: local notes
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.
In and around Keymer, as anywhere, good new build mastic starts with a clean, dry, properly prepared joint.
Keymer is about 2 miles south of Burgess Hill, in West Sussex. Jobs in Keymer get the same care as everywhere else we work: old sealant removed completely, careful preparation and a 12-month guarantee. Keymer is one of 371 places in West Sussex we cover for new build mastic. For nearby work, see our Brighton page, about 6 miles away.
Here we cover the BN6 postcode area for new build mastic. You will find streets such as Flowers Close, The Quadrant and Kymer Gardens. Nearby, we also carry out new build mastic in Hassocks (1 mile west), Ditchling (1 mile east), Clayton (1 mile south-west), Hurst Wickham (1 mile north-west) and Westmeston (2 miles south-east). Further out, we also cover Crawley (13 miles north), Horsham (13 miles north-west), Worthing (14 miles south-west), Haywards Heath (5 miles north), East Grinstead (15 miles north) and Shoreham-by-Sea (8 miles south-west).
Near you in Keymer
Around Keymer, our work takes us to homes and buildings near The Greyhound Public House and Downlands Community School, among other places. For rail, the closest station is Hassocks station, about 0.5 miles west. Nearby you will also find The Dene Hospital (3.2 miles north-west) and Clayton Castle (1.2 miles south-west). Not far away are Ditchling Beacon and Bedelands Farm Nature Reserve.
Keeping the joints in good condition
So the new joints stay in good condition:
- Open a window or run the fan after bathing
- Resist patching a failed seal with a tube from the DIY shop
- Raise failed sealant with the developer while you’re covered
- Wipe joints with warm soapy water
Keep the bathroom ventilated, especially in the first year. Run the fan or open a window after bathing to help keep mould away.
A seal that splits early is often a sign of movement. Have it resealed, and the tray or bath checked, before it gets worse.
What happens on the day
Before we leave, we go over the finished joints with you. The visit itself normally takes anything from a few hours to several days, depending on the number of plots, depending on the size of the job. For a job in Keymer, we agree the time, the access and parking before the day. If the work is outside, the weather plays a part, as sealant needs a dry surface.
- First we work through your snagging list or plot schedule with you.
- We cut out every bit of the failed or messy sealant.
- Each joint is cleaned of dust and grit, then primed if required.
- 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.
How to prepare
- For business premises, tell us about site rules or sign-in
- Keep pets and children clear of the area while we work
- Let us know about parking restrictions
How to get a quote
We don’t publish a price list, because every job is different. Instead, we give you a clear quote for your job. To arrange one, call 0345 464 0079 or drop us an email.
Advice
Nearby places to Keymer
Also in Keymer
DIY sealant or a professional job?
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it lifts and traps water and mould underneath. All the old material has to come out first.
What happens if it’s left?
If you are still in the builder’s snagging or warranty period, ask them to put it right first. If it keeps failing or isn’t dealt with, we can reseal it properly. Homes in smaller places like Keymer can face more weather, and failed outside joints let damp into walls. Inside, a split seal lets water into floors and panels just as it would anywhere.
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote.
Why choose Mr Mastic in Keymer
- Domestic, commercial and hotel work
- White, clear, grey or another colour, product permitting
- An ARBOMaster approved applicator
- Anti-fungal sanitary silicone in wet areas
What the job involves on each surface
Skirting and floors
As timber and screed dry, skirting and floors shift. Caulk cracks; a flexible sealant moves with it painted or coloured to suit.
Kitchens
Sink joints are wet all the time. A kitchen sealant goes in there suited to the job.
Landlords, agents and businesses in Keymer
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we’ll give you a quote.
In hotels, rooms out of use cost money, so the work can be planned room by room. We have worked in hotels as well as homes and businesses.