Greater London · England
External Mastic in Bandonhill
Problem with your movement joints in Bandonhill? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Plants rooting in failed movement joints
- Gaps where render, brick and frames meet
- Rigid filler in a joint that should flex
For landlords and businesses
Mouldy or split sealant often shows up at the end of a tenancy, and it’s quick to put right between tenancies. Several properties can go on one quote.
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Keeping joints in good order is simple maintenance that we can handle for you.
How we handle external mastic in Bandonhill
A movement joint is a deliberate break that lets a wall expand and contract. Its sealant has to flex with the building, season after season, so once it splits or hardens, the joint stops working and water gets in. Common call-outs are for failed seals between different materials and joints pointed up with cement by mistake, across copings & trims, façade panels and render & cladding joints.
Modern London flats rely on sealed movement joints and cladding joints. Period houses have different weak points, such as gutter joints, trims and the line where an extension meets the old wall, and both kinds of building are found across London.
A one-year guarantee comes as standard, so you’re not left on your own once the job is done.
- Location
- Bandonhill (SM6, CR0, CR9)
- Region
- Greater London
- Cover
- 12 months on all our work
- Price
- A clear price before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
How we quote for external mastic
There’s no set price list. The quote depends on:
- The number and length of the joints
- How many rooms, windows or areas are involved
- Whether old sealant or filler has to be cut out
- Working hours on commercial sites
A failed joint rarely gets cheaper to fix by waiting. If you’re not sure whether it needs doing, call 0345 464 0079 or drop us an email and we will give you an honest view and a quote.
What we need to know
To make quoting easier, let us know:
- Whether it has been sealed before
- What the problem is, such as mould, gaps, leaks or cracking
- Where the property is
- Pictures of the joints, sent by email
We don’t publish a price list, because every job is different. Instead, we give you a clear price for your job. To arrange one, phone 0345 464 0079 or send us an email.
When it isn’t the sealant
We’ll always be straight with you, so here’s what new sealant will not do:
- Structural movement, which needs a surveyor or engineer
- Damp that isn’t coming from the joint
- Adding movement joints to masonry that has none
If you are not sure, just phone 0345 464 0079 or email us and we’ll give you a straight answer.
Surfaces we seal
- Render & cladding joints
- Façade panels
- Concrete & block
- Copings & trims
- Joints between brick and frames
- Brickwork movement joints
Bandonhill questions
Can you do external mastic in Bandonhill?
Yes. We work across London and the South East, and Bandonhill is part of that. Just ring 0345 464 0079 or send us an email with a few details of the job, and we’ll give you a clear price.
Can parking be tricky for a visit in Bandonhill?
Parking in Bandonhill, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly, so mention what’s available when you book.
What’s an expansion joint in brickwork?
It’s a deliberate gap that lets the wall expand and contract without cracking. It’s sealed with a flexible sealant, not mortar.
What does external mastic cost?
Size, access and the old material all affect the cost. Call for a quick quote.
Do I have to be there?
We need access to the joints, so we will agree that with you when we book. Indoors, that normally means someone at home.
When is the sealant fully cured?
Different products cure at different speeds, so please follow the time we give you.
Can tenants book the work?
Yes, though it’s best to check with your landlord first. Many landlords are glad to have it sorted.
Can I add another job to the visit?
Yes, we can. More than one area can go on one quote.
What we do, step by step
There’s no need to move everything out, just the space around the work. We protect the rest, and the work takes a few hours to a few days, depending on the length of joint and the access in most cases. In Bandonhill, flats, stairs and shared entrances are part of the routine. If the building has a concierge, managing agent or access rules, tell us when you book.
- We look at every joint and agree a colour to suit the wall.
- 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.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
How to prepare
- On commercial sites, let us know about site rules
- Tell us if parking is tricky
- Mention any leaks or damp you’ve noticed
Ask for a quote
For a quote, phone 0345 464 0079 or email us and tell us where the job is and what the problem looks like. We will give you a clear quote before any work starts.
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Places near Bandonhill
More services for Bandonhill
Outside joints around Bandonhill
Historic houses like Addington Palace (about 4 miles east) are a reminder that the area around Bandonhill has older buildings as well as new. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth. 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.
If you look after a building such as High View Primary School, larger buildings have long runs of movement joint that eventually need resealing. As a London address, Bandonhill can be tricky for parking: tell us about permits, visitor bays or off-street space when you book. Letting a property close to Waddon station? Then split movement joints are easy to miss on a rental until damp shows inside.
Bandonhill is about 2 miles west of Croydon, in Greater London. Anywhere in SM6, we can carry out external mastic at your property. Bandonhill is one of 764 towns and villages in Greater London we cover. Our London page covers work nearby.
Every address in SM6, CR0 and CR9 is within our area for external mastic, from the main roads to the quietest streets. Whether your property is on Guy Road, Ross Road and Link Lane or a nearby road, we can help. Close by, we work in Beddington (1 mile north), Roundshaw (1 mile south), Wallington (1 mile west), Russell Hill (1 mile south) and Waddon (1 mile east). Within a short drive, we also cover London (10 miles north), City of Westminster (10 miles north), Marylebone (11 miles north), Kensington (10 miles north), St Pancras (11 miles north) and Shoreditch (11 miles north).
Near you in Bandonhill
Typical jobs here are in homes near Wilson's School, Beddington Park and The John Fisher School, among other places. For rail, the closest station is Waddon station, about 0.7 miles east. Other landmarks nearby include Purley War Memorial Hospital (1.8 miles south-east) and Croydon Airport Visitor Centre (0.8 miles south-east). Open spaces near Bandonhill include Duppas Hill and Roundshaw Downs.
What happens if it’s left?
The longer a joint stays open, the more water the wall takes in. Wet masonry is more easily damaged by frost, so the damage spreads beyond the joint. Converted houses in London often have a bathroom above someone else’s living room, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Dealing with it early is far simpler for homes in Bandonhill.
No two jobs are quite the same, so we quote each one individually. The number of joints, how easy they are to reach and the sealant needed all make a difference, and we will explain the quote if you ask.
What you get with us
- Fully insured
- 180+ five-star Google reviews
- Any old sealant cut out fully, not covered over
- Trusted Arbo and Everbuild sealants
Take a look at our cost guide and what customers say.
Should I try it myself first?
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
The biggest DIY mistake is sealing over old sealant. New silicone won’t bond to old, so it peels away and traps moisture behind it. All the old material has to come out first.
Aftercare tips
How long the joints last depends on use and care. Here’s what we suggest:
- Never let anyone fill a movement joint with mortar
- Keep high-pressure jets off the joints
- Point out the joints to other trades
- Check the sealant is paintable before painting near it
Avoid pressure-washing straight into the joints. High-pressure water can lift the edges.
Once a joint cannot move, the wall finds another way, often as cracks near the joint. Resealing it early helps prevent that.