Kent · England
External Mastic in How Green
We cover How Green for sealing brickwork movement joints, render, cladding and façade joints. Old sealant removed completely, joints prepared properly and a 12-month guarantee.
- Weathered mastic that no longer stretches
- Sealant that has lost its bond to the brick or render
- Weeds or debris growing in open joints
When something else is needed
We will not take on work that will not last, so these are the limits:
- Cracks in the bricks or render themselves, away from the joints
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Movement that is more than a sealant joint can take
If you’re not sure, just phone 0345 464 0079 or drop us an email and we’ll give you a straight answer.
Surfaces we seal
- Façade panels
- Joints between brick and frames
- Copings & trims
- Brickwork movement joints
- Concrete & block
- Render & cladding joints
About our external mastic in How Green
Low-level joints can generally be done from the ground. For joints higher up, give us some details of the building and we’ll confirm what access is needed. We work on façade panels, copings & trims and brickwork movement joints, and common reasons people get in touch are water getting into walls through failed joints and failed sealant between panels on a façade.
Somewhere as small as How Green, homes and farm buildings often face open ground, where walls and rooflines take the weather head on. Joints on those walls need a sealant that moves with the building and stays in place.
There’s a 12-month guarantee on every job, large or small.
- Location
- How Green (TN8)
- Wider area
- Kent
- Cover
- 12 months on all our work
- Quote
- Quoted before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
How we quote for external mastic
We don’t publish a price list, because jobs vary so much. The quote depends on:
- The type of sealant required
- Whether there’s mould to deal with
- How many rooms, windows or areas are involved
- How easy the joints are to reach
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please ring 0345 464 0079 or drop us an email and we will talk you through it.
What we need to know
When you call or email, these details help:
- Access, such as stairs, a lift or height
- Whether it’s a home or a business
- Any previous sealing or DIY work
- Where the property is
We don’t publish a price list, as no two jobs are quite the same. Instead, we send you a clear quote for your job. To arrange one, call 0345 464 0079 or email us.
How the job changes by surface
Brickwork movement joints
Vertical joints in long brick walls let the brickwork expand without cracking. They’re resealed over backing rod with a low-modulus sealant coloured to suit the wall.
Copings and trims
A failed coping joint lets water into the top of the wall. Sealing them early saves the wall below.
DIY sealant or a professional job?
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.
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
Towns and villages near How Green
More services for How Green
How it works
A visit follows a simple pattern: we look at the joints together, mask and protect the surrounding surfaces, carry out the job and clear up. Most jobs take a few hours to a few days, depending on the length of joint and the access. Somewhere as small as How Green, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- Each joint is checked and the colour of the new sealant agreed.
- We take out the old sealant until the faces are sound.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
How to prepare
- For business premises, tell us about site rules or sign-in
- Tell us about any previous sealing or DIY attempts
- Plan for the work area to be out of bounds to pets and children
Getting a quote
To get a quote, ring 0345 464 0079 or email us and tell us where the job is and what the problem looks like. You will have a clear quote before we start.
Related advice
External mastic in How Green: local notes
London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Hever Castle (about 0.7 miles south) are a reminder that the area around How Green has older buildings as well as new. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
Schools such as Hever Church of England Voluntary Aided Primary School are buildings too, and movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. Homes close to Church of St Peter include some older properties, and older walls, gutters and the joints where extensions meet them need a flexible sealant. For landlords with property near Hever station, failed wall and movement joints let damp in, so they’re worth checking between tenancies.
How Green is about 7 miles south-west of Sevenoaks, in Kent. Our applicators cover external mastic for homes and businesses in How Green and the surrounding area, as part of our work across Kent. We cover 922 towns and villages across Kent, large and small. There’s also a page for Crawley, about 14 miles away.
Postcode districts we cover here for external mastic: TN8. Local streets include Hever Road and How Green Lane, and we cover them all. Other places close to How Green include Hever (1 mile south), Newtown (2 miles south), Markbeech (2 miles south), Chiddingstone Causeway (3 miles east) and Chiddingstone Hoath (3 miles south-east). Within a short drive, we also cover Sevenoaks (7 miles north-east), Royal Tunbridge Wells (8 miles south-east), Tonbridge (7 miles east), Swanley (14 miles north), Kings Hill (14 miles east) and Paddock Wood (12 miles east).
Local landmarks in How Green
Around How Green, our work takes us to homes and buildings near The Wheatsheaf Public House and Chiddingstone Castle Park and Gardens and the streets around them. How Green’s nearest station is Hever station, roughly 1.3 miles south-west. A little further out are Tandridge Priory (5.4 miles north-west) and Hever Castle (0.7 miles south).
Why deal with it now?
A properly done movement joint is an even line in a colour that suits the wall. A hurried job with smeared edges and no backing looks worse and fails sooner so it’s worth doing right. Where a wall is exposed, as many are in small places like How Green, wind-driven rain gets into any failed joint, and damp in older walls is slow to dry out.
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether the work is at height. Your quote takes all of that into account.
Why choose Mr Mastic in How Green
- Domestic, commercial and hotel work
- Anti-fungal sanitary silicone in wet areas
- Arbo and Everbuild products
- We agree the colour with you first
See our cost guide or customer reviews.
Common questions in How Green
Can you do external mastic in How Green?
Yes, How Green is within the area we cover. We work across London and the South East. You can phone 0345 464 0079 or drop us an email and tell us what needs doing.
Can you help a landlord with a rental near Hever station?
Yes, landlords and agents are among the people we work for. Just ring 0345 464 0079 or drop us an email with the address and what needs doing, and we’ll send you a clear quote.
Is it OK to seal over old sealant?
No, because it fails. The old sealant always comes out first, so the new joint bonds to clean surfaces.
Is the work guaranteed?
Yes. There’s a 12-month guarantee on every job.
Is there any odour?
Sometimes, a little. Any smell clears as the sealant cures, and ventilation helps.
When will the joints need doing again?
It varies with how exposed the wall is and how much the joint moves. Signs to watch for are cracking, hardening and gaps at the edges.
Which products do you use?
Quality sealants from brands including Arbo and Everbuild, chosen to suit the joint. We explain the product when we quote.
Are you fully insured?
Yes. Full insurance covers our work, and we can confirm the details when we quote.
Landlords, agents and businesses in How Green
If you manage several properties in or around How Green, several properties can go on one quote. Just tell us the addresses and what each one needs, and photos by email help.
In hotels, rooms out of use cost money, so we plan the work room by room. We have worked in hotels as well as homes and businesses.