Greater London · England
Berry's Green External Mastic
External mastic in Berry's Green from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Movement joints filled with mortar instead of sealant
- Joints with sealant missing in places
- Weeds or debris growing in open joints
External mastic for homes and businesses in Berry's Green
We cut out failed sealant, set the joint depth with closed-cell backing rod and reseal with a low-modulus exterior sealant. The colour is chosen to suit the brick or render so the line blends in. If you’re dealing with hard, crazed mastic that has stopped moving and movement joints with cracked, split or missing sealant, we can help, on joints between brick and frames, render & cladding joints and concrete & block alike.
Newer London blocks are built with movement joints in brick and render, and with cladding joints sealed with mastic. Older terraces have their own weak points: gutter joints, roofline trims and the joint where an extension meets the original wall, and both kinds of building are found across London.
You get a one-year guarantee, the same in Berry's Green as everywhere else we work.
- Where
- Berry's Green (TN16)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Quote
- A clear price before we start
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Different surfaces, different methods
Render joints
Rendered walls have joints at beads, openings and changes of material. They’re resealed in a sealant that suits the render.
Joints between dissimilar materials
Different materials may need different primers. Both surfaces are cleaned and primed as the product requires.
Berry's Green buildings and the weather
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. London terraces and converted houses often share gutters, downpipes and walls, so it’s worth agreeing who is responsible before work starts.
Berry's Green is in London, so parking needs planning: let us know about parking bays, permits or a driveway. Schools such as Cudham Church of England Primary School are buildings too, and larger buildings have long runs of movement joint that eventually need resealing.
Berry's Green is about 5 miles south of Orpington, in Greater London. For external mastic in and around Berry's Green, please call 0345 464 0079 or drop us an email for a quick quote. We’re based in Crawley and cover Greater London. We cover 764 towns and villages across Greater London, large and small. Our London page covers work nearby.
All of TN16 is covered for external mastic. Local streets include Berry's Green Road, St Margarets Avenue and St Johns Rise. Close by, we work in Single Street (1 mile north), Cudham (1 mile north-east), Luxted (1 mile north-west), Aperfield (1 mile south-west) and Horns Green (1 mile south-east). Within a short drive, we also cover London (15 miles north-west), Whitechapel (15 miles north), Stockwell (13 miles north-west), Orpington (5 miles north), Wimbledon (14 miles north-west) and Plaistow (15 miles north).
Local landmarks in Berry's Green
Typical jobs here are in homes near Charles Darwin School and The Old Jail Public House. For rail, the closest station is Chelsfield station, about 3.6 miles north-east of the centre. A little further out are Princess Royal University Hospital (3.6 miles north). Green spaces nearby include Betsom's Hill and Downe Bank.
What happens on the day
Before we leave, we go over the finished joints with you and explain the cure time. The work normally takes a few hours for a handful of joints, longer for a whole elevation, depending on the size of the job. In Berry's Green, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- We start by checking each joint, agreeing the ones to redo and how we will reach them.
- We cut out the failed sealant and rake out any dirt or growth.
- We clean both faces of the joint and prime them where the product calls for it.
- Backing rod goes in next, setting the depth and keeping the sealant off the back of the joint.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
Getting ready for the visit
- Plan for the work area to be out of bounds to pets and children
- Mention any sign-in or site rules at work premises
- Where the joints are inside, avoid wetting them before we arrive
How to get a quote
To get a quote, phone 0345 464 0079 or drop us an email with the location and a short description of the problem. You’ll have a clear quote before work begins.
Read more
When to call us in Berry's Green
A lot of failed joints come down to preparation: joint faces that were dusty or damp, unprimed where they needed it, or still carrying old sealant. The sealant never bonds properly.
Any of these means the joints need attention:
- Rain getting behind render or cladding at a joint
- Sealant pulling away from one side of the joint
- Weeds or debris growing in open joints
- Cracked joints where brick meets render or frames
Letting a property close to Chelsfield station? Then split movement joints are easy to miss on a rental until damp shows inside.
What to look for in a quote
- How the joint is cleaned and prepared
- Who turns up on the day
- What happens if they find a problem under the old sealant
- How the colour is chosen
When it isn’t the sealant
Before you book, it’s worth knowing the limits too:
- Cracks in the bricks or render themselves, away from the joints
- Render that’s blown, hollow or coming away
- Structural movement, which needs a surveyor or engineer
If in doubt, ring 0345 464 0079 or email us and we’ll say what we think.
What we seal
- Copings & trims
- Joints between brick and frames
- Render & cladding joints
- Concrete & block
- Brickwork movement joints
- Façade panels
Aftercare tips
Looking after new joints is easy, and it makes a real difference:
- Make sure movement joints are not pointed over
- Check the sealant is paintable before painting near it
- Show decorators and builders where the movement joints are
- Act on the first splits you see
Have a quick look at the joints each spring. Splits, gaps at the edges or plants in the joint are early warning signs.
Leaks behind façade panels and render often go unseen. By the time there’s a damp patch, the damage can be well established.
Why act early in Berry's Green
A properly done movement joint is an even line in a colour that suits the wall. A rushed bead with no backing looks untidy and does not last. In London conversions, one flat’s bathroom is often above another flat’s ceiling, and a slow leak from a failed seal can end up in the flat below. Putting it right early is much less trouble for homes in Berry's Green.
Some things make a job bigger or smaller: the old material and how easily it comes out, any mould to treat, and whether the work is at height. We take all of that into account in your quote.
Why choose Mr Mastic in Berry's Green
- More than 20 years in sealant work
- White, clear, grey or another colour, product permitting
- A sealant colour to suit the surroundings
- 180+ five-star Google reviews
See our cost guide and customer reviews.
Your questions about external mastic in Berry's Green
Can you do external mastic in Berry's Green?
Yes. Our work covers London and the South East, and Berry's Green is part of that. You can phone 0345 464 0079 or send us an email and tell us what needs doing, and we will send you a clear quote.
Can parking be tricky for a visit in Berry's Green?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. The visit is then planned around what’s available.
Do you guarantee your work?
Yes, for a year. If anything is not right with the work within the year, let us know and we will sort it.
Where is Mr Mastic based?
We’re based in Crawley, and we work across South East England, London and Scotland.
Do you work for landlords and businesses?
Yes. We work for homeowners, landlords, letting agents, businesses and hotels across Greater London.
Will there be a smell?
It depends on the product. Some products have a noticeable smell, others very little.
What’s an expansion joint in brickwork?
Most straight vertical gaps in brickwork are movement joints. It gives the wall room to move and needs a flexible seal, not mortar.
Can I do it myself?
For a simple, easy-to-reach joint, a careful DIYer can do a reasonable job. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
Towns and villages near Berry's Green
What else we do in Berry's Green
Can I do it myself?
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
The biggest DIY mistake is sealing over old sealant. Silicone doesn’t stick to old silicone, so it peels away and traps moisture behind it. Everything old must be removed first.