Kent · England
Key's Green External Mastic
External mastic for Key's Green and the surrounding area: the right sealant, proper preparation and a neat finish. Ask us for a quick quote.
- Joints with sealant missing in places
- Rain getting behind render or cladding at a joint
- Movement joints filled with mortar instead of sealant
How we handle external mastic in Key's Green
Ground-floor and low-level joints are straightforward to reach. For joints higher up, give us some details of the building and we will confirm what’s needed to reach them safely. Common call-outs are for cracked joints where brick meets render or frames and hard, crazed mastic that has stopped moving, across joints between brick and frames, copings & trims and façade panels.
In a village or hamlet like Key's Green, older cottages and farm buildings often stand in the open, so walls and rooflines take the full force of wind and rain. Joints on those walls need a sealant that moves with the building and stays in place.
We stand behind the work with a 12-month guarantee, so you’re not left on your own once the job is done.
- Where
- Key's Green (TN12)
- Wider area
- Kent
- Guarantee
- A year, on every job
- Quotes
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
DIY versus a professional finish
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.
If you do try it yourself, take your time over the preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
Why act early in Key's Green
A failed movement joint lets water into the wall, behind render and cladding. Dealing with it early keeps the repair to the joint, rather than the wall around it. Where a wall is exposed, as many are in small places like Key's Green, wind-driven rain gets into any failed joint, and older walls, once damp, take a long time to dry.
Combining jobs into one visit normally makes better use of the time than several visits. We will send you a clear quote for the lot.
Why book with us
- 4.9 on Google from 180+ five-star reviews
- White, clear, grey or coloured to suit, where the product allows
- Anti-fungal silicone where joints get wet
- Quality sealants from Arbo and Everbuild
See our cost guide and what customers say.
Landlords, agents and businesses in Key's Green
Whether it’s one flat or a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance that we can handle for you.
Key's Green: your questions answered
Is Key's Green in your area for external mastic?
Yes, Key's Green is within the area we cover. We work across London and the South East. You can phone 0345 464 0079 or email us and let us know what needs doing, and we will send you a clear quote.
I let a flat near Frant station. Can you help?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. Just ring 0345 464 0079 or send us an email with the address and what needs doing, and we’ll give you a clear quote.
Do you have insurance?
Yes, we are fully insured for every job we do.
How often do external joints need resealing?
That varies with the weather the wall faces, how much it moves and the sealant used. Treat it as a maintenance item and look at it yearly.
How long will you be here?
It depends on the size of the job, but most jobs take a few hours for a handful of joints, longer for a whole elevation. We’ll tell you when we quote.
Can you seal joints between render and window frames?
Yes. Different materials move at different rates, so a flexible sealant is needed where they meet. The sealant is matched to both sides.
What do you need from me for a quote?
The location, the problem and the rough size of the job. If you can, email a few photos.
Do I have to be there?
It depends on the job. Inside work needs someone to give us access, while outside work can sometimes be arranged differently.
The process
Before we leave, we go over the finished joints with you. The work normally takes a few hours to a few days, depending on the length of joint and the access, depending on the size of the job. Somewhere like Key's Green needs a little journey planning: 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 checking each joint, agreeing the ones to redo and how we’ll reach them.
- The old mastic and anything lodged in the joint is removed.
- Both sides are cleaned back to sound material and primed if needed.
- Backing rod goes in next, setting the depth and keeping the sealant off the back of the joint.
- The new sealant, chosen to suit the brick or render, is applied and tooled to a neat finish.
Before we arrive
- On commercial sites, let us know about site rules
- Let us know about stairs, lifts or work at height
- Mention any parking rules near the property
Ask for a quote
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we’ll explain how we’d tackle it. Whenever you are ready, phone 0345 464 0079 or drop us an email.
Advice
Different surfaces, different methods
Render joints
Cracks along render joints let water in behind the coat. A sound joint keeps the render dry behind and helps it last.
Joints between dissimilar materials
Each side of the joint may need its own preparation. Both surfaces are cleaned and primed as the product requires.
Do you need external mastic in Key's Green?
Some movement joints have been pointed up with mortar. The joint can’t move, so the wall cracks somewhere else instead.
These are the problems we’re asked about most:
- Rigid filler in a joint that should flex
- Weeds or debris growing in open joints
- Sealant pulling away from one side of the joint
- Gaps where render, brick and frames meet
Rented homes near Frant station change hands often, and split movement joints are easy to miss on a rental until damp shows inside.
Before booking anyone
- What guarantee comes with the work
- Whether you can choose the colour
- What the quote includes, VAT included or not
- Whether all the old sealant comes out first
What we cannot put right
Sealant isn’t the answer to every problem, and we’ll tell you before we start. It won’t solve:
- Render that is blown, hollow or coming away
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Walls that need new movement joints cut into them
Not sure which it is? You can ring 0345 464 0079 or drop us an email and we will tell you honestly before you book.
What we seal
- Brickwork movement joints
- Copings & trims
- Joints between brick and frames
- Façade panels
- Render & cladding joints
- Concrete & block
Walls and rooflines in Key's Green
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. With historic houses such as Scotney Castle (about 3.6 miles south-east) nearby, there’s older building stock in the area around Key's Green as well as newer homes. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth.
Homes close to Chapel Of Ease Of St Luke include some older properties, and old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Key's Green is about 4 miles east of Royal Tunbridge Wells, in Kent. We provide external mastic to homeowners, landlords and businesses in Key's Green and the surrounding area, as part of our work across Kent. We cover 922 towns and villages across Kent. For nearby work, see our Crawley page, about 24 miles away.
Jobs for external mastic in TN12 is quoted and booked the same way as anywhere else. External mastic is available to properties on Cryals Road and Beech Lane. We also cover the places around Key's Green: Lamberhurst Quarter (1 mile south), Petteridge (1 mile north-east), Pembury (2 miles north-west), Matfield (2 miles north-east) and Brenchley (2 miles north-east). Larger places within reach include Maidstone (12 miles north-east), Sevenoaks (13 miles north-west), Royal Tunbridge Wells (4 miles west), Tonbridge (6 miles north-west), Kings Hill (10 miles north) and Foley Park (13 miles north-east).
Near you in Key's Green
Around Key's Green, our work takes us to homes and buildings near Brenchley Wood and The Blue Boys Inn, among other places. Key's Green’s nearest station is Frant station, roughly 3.5 miles south-west. Well-known places in the area include Pembury Hospital (2.4 miles north-west) and Old Scotney Castle (3.7 miles south-east). For a walk, there’s Bewl Water and Tudeley Woods RSPB reserve.