Kent · England
New-build mastic & snagging in Underriver, Kent
New-build sealant joints in Underriver need attention? We remove the old material, prepare the joints and seal them properly.
- Cracks appearing as a new home settles
- Frame joints opening as the plaster dries
- Smeared, uneven beads picked up at snagging
New build mastic in Underriver, done properly
If your new home has a leaking shower seal, open skirting joints or untidy sealant, we can help. If you’re still within the builder’s snagging or warranty period, tell them first, and if it isn’t put right, get in touch with us. We work on plot handovers, show homes and skirting & floors, and the jobs we see most are cracked caulk along new skirting and worktop and upstand sealant coming away.
Older homes in small places like Underriver often have timber floors that move with the seasons, which is why skirting and threshold joints need a flexible sealant, not filler.
There’s a 12-month guarantee on every job.
- Where
- Underriver (TN15)
- Region
- Kent
- Guarantee
- A year, on every job
- Quote
- A clear quote up front
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
When it isn’t the sealant
New sealant cannot fix everything, and we’d rather say so up front. It will not solve:
- Settlement cracks that need a surveyor
- Leaks from pipes, valves or wastes, which need a plumber
- A tray or bath that isn’t properly supported, until it’s fixed
Not sure which it is? You can phone 0345 464 0079 or send us an email and we’ll tell you honestly.
Joints and surfaces we work on
- Skirting & floors
- Plot handovers
- Bathrooms & en suites
- Windows & doors
- Show homes
- Kitchens
DIY sealant or a professional job?
A DIY attempt does not rule out a professional job. We remove it and do the joint properly, so tell us about it when you ask for a quote.
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Why deal with it now?
If you’re still in the builder’s snagging or warranty period, ask them to put it right first. If it keeps failing or is not dealt with, we can reseal it properly. Where a wall is exposed, as many are in small places like Underriver, wind-driven rain gets into any failed joint, and damp in older walls is slow to dry out.
Instead of a standard rate, we look at what your job involves: how many joints, what’s in them now and how we reach them. You will know the price before we begin.
Why Underriver customers choose us
- Old sealant always removed completely
- We’re fully insured
- A sealant colour to suit the surroundings
- Over 20 years’ experience
Quotes for new build mastic in Underriver
The price is agreed before any work begins. It takes into account:
- The size of the job
- Whether old sealant or filler has to be cut out
- How many areas need sealing
- The type of sealant required
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote and we’ll talk you through it.
Asking for a quote
To make quoting easier, let us know:
- Any previous sealing or DIY work
- Roughly how big the job is
- Pictures of the joints, sent by email
- The address or postcode of the job
Call for a quick quote, or send an email if you’d rather. Tell us about the joints that need doing and we will talk you through the work and give you a clear quote.
Places near Underriver
Other services in Underriver
Common questions in Underriver
Can you do new build mastic in Underriver?
Yes, Underriver is within the area we cover. Our work covers London and the South East. Just ring 0345 464 0079 or send us an email with a few details of the job.
Is Underriver within the area you cover?
Yes, we do. We work across London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Who should fix failed sealant in a new build?
Your builder, if you are still in their snagging or warranty period. If that does not work out, we are happy to quote.
Can landlords and businesses book you?
Yes, regularly. Several properties can be quoted together.
Can you reseal over the builder’s sealant?
No. Over-sealing traps mould and water and soon fails. We remove every bit of the old bead before resealing.
What do you put in the joint?
Products from Arbo and Everbuild, among others, chosen to suit the joint. We’ll tell you what we’re using and why.
Will you leave a mess?
Not at all. We work neatly, protect the area around the joints and tidy up afterwards.
How do I get a quote for new build mastic in Underriver?
Size, access and the old material all affect the cost. Ask us for a quote and we will talk you through it.
Common problems we fix in Underriver
On many sites, sealant goes on in the final rush before handover. Joints aren’t always cleaned of dust or primed, and the sealant sits on grit instead of the surface.
If you can see any of these, it’s time to have the joints looked at:
- Gaps between new skirting and floors
- Joints pulling apart as timber shrinks
- Beads laid onto grit and dust from the build
- Cracked sealant around new window and door frames
If you’ve bought a new home near Hildenborough 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
- What preparation is included
- What insurance they hold
- Whether VAT is included
Joints and finishes in Underriver homes
The South East is one of the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Around Underriver, as everywhere, new build mastic is only as good as the preparation behind it.
Underriver is about 3 miles south-east of Sevenoaks, in Kent. We provide new build mastic to homes and businesses in Underriver and nearby, as part of our work across Kent. Our area takes in 922 places across Kent. We also work in Crawley, about 20 miles from Underriver.
We cover every part of TN15 for new build mastic. We also cover the places around Underriver: Budds (1 mile east), Bitchet Green (1 mile north-east), Watt's Cross (2 miles south), Godden Green (2 miles north) and Stone Street (2 miles north-east). We also work in nearby towns such as Maidstone (13 miles east), Dartford (14 miles north), Sevenoaks (3 miles north-west), Royal Tunbridge Wells (8 miles south), Gravesend (14 miles north-east) and Tonbridge (4 miles south-east).
What’s near Underriver
Around Underriver, our work takes us to homes and buildings near Knole Park and the streets around them. For rail, the closest station is Hildenborough station, about 2.3 miles south of the centre. Well-known places in the area include Sevenoaks Museum (2.2 miles north-west) and Tonbridge Castle (4 miles south-east). The countryside around Underriver includes Dryhill Nature Reserve and Barden Lake.
Aftercare tips
No joint lasts for ever, but care makes a real difference. A few tips:
- Report sealant problems to your builder during the snagging period
- Avoid running a DIY bead over the old one
- Clean sealant with mild detergent, not abrasives
- Ventilate bathrooms well, especially in the first year
Follow the cure time we give you before the area gets wet. Most silicones need around a day.
Early snagging is easier snagging. Left alone, a small crack can become a leak in a busy bathroom.
How the visit works
There’s no need to move everything out before we come, only the area right around the joints. Everything nearby is protected, and the work takes anything from a few hours to several days, depending on the number of plots in most cases. For a village or hamlet like Underriver, the journey is planned in advance: let us know about lanes, gates and parking. We bring what the job needs, so it can be finished in one trip where possible.
- We start by going through the snagging items or plot schedule with you.
- Every bit of the old builder’s sealant is cut out down to clean surfaces.
- We clean out the dust and grit left from the build.
- We prime where needed and apply a sealant suited to each joint.
- Each bead is tooled and the cure times explained.
Before we arrive
- Mention any tricky access
- Keep pets and children clear of the area while we work
- Tell us if parking is tricky
How to get a quote
To get 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’ll give you a clear quote before any work starts.