Greater London · England
External & façade joints in Riddlesdown, Greater London
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Riddlesdown and across Greater London. Fully insured, ARBOMaster approved and guaranteed for a year.
- Leaking joints around cladding and façade panels
- Movement joints with cracked, split or missing sealant
- Failed seals between different materials
External mastic in Riddlesdown
We cut out failed sealant, set the joint depth with closed-cell backing rod and reseal with a low-modulus exterior sealant. We pick a colour that sits well with the wall so the line blends in. We are often asked to deal with joints pointed up with cement by mistake and failed sealant between panels on a façade, on façade panels, brickwork movement joints and copings & trims.
Outside work in London starts with access: side passages, upper floors and where to park. In Riddlesdown, joints up high may need ladders or other access, which is worth talking through when you book.
A 12-month guarantee comes with the work, just as it does everywhere we cover.
- Place
- Riddlesdown (CR8, CR2)
- Region
- Greater London
- Cover
- 12 months on all our work
- Quotes
- A clear quote up front
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
The process
On the day, we look over the joints with you first. Surfaces next to the work are protected before we start. Most jobs take a few hours for a handful of joints, longer for a whole elevation. In Riddlesdown, flats, stairs and shared entrances are part of the routine. Mention any building rules, key holders or managing agents 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.
- Backing rod goes in so the sealant can stretch between the two faces.
- We prime the faces where required.
- We gun in low-modulus sealant and tool it neatly.
How to prepare
- For business premises, tell us about site rules or sign-in
- Tell us about any water getting in
- Clear items away from the joints we are working on
Get a quote
Want a quote for external mastic? Please phone 0345 464 0079 or send us an email with a few details. You’ll know what we plan to do, and what it will cost, before any work begins.
Related advice
Riddlesdown questions
Do you cover Riddlesdown for external mastic?
Yes. Our work covers London and the South East, and Riddlesdown is part of that. Just call 0345 464 0079 or send us an email with a few details of the job.
Can parking be tricky for a visit in Riddlesdown?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. That way the visit can be planned around it.
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.
What is a movement joint?
A vertical gap in a long brick wall is generally a movement joint. It lets the bricks expand without cracking.
Can you work on commercial sites?
Yes. We have worked for hotels, offices and other businesses, and we are fully insured.
Are you insured?
Yes. We’re fully insured, and we can confirm the details when we quote.
Should I point up the gap in my brickwork?
No. A mortar-filled joint can’t move, so the wall cracks somewhere else instead. It needs a flexible sealant over backing rod.
What do you put in the joint?
The product depends on the job: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. Brands we use include Arbo and Everbuild.
Riddlesdown buildings and the weather
Rainfall in the South East is lower than in much 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 Addington Palace (about 3 miles north-east) nearby, there’s older building stock in the area around Riddlesdown as well as newer homes. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth.
If you look after a building such as Harris Primary Academy Kenley, larger buildings have long runs of movement joint that eventually need resealing. If you let a flat or house near Riddlesdown station, split movement joints are easy to miss on a rental until damp shows inside.
Riddlesdown is about 1 mile east of Purley, in Greater London. For external mastic in and around Riddlesdown, it’s easy to get a quote: please ring 0345 464 0079 or email us. We cover Greater London from our Crawley base, Riddlesdown included. Our Greater London coverage runs to 764 places, and Riddlesdown is one of them. London is on our list too, about 12 miles from Riddlesdown.
Jobs for external mastic in CR8 and CR2 is quoted and booked the same way as anywhere else. External mastic is available to properties on Hyde Road, Lower Road and Famet Avenue and the roads around them. Riddlesdown is on the A22, which makes it straightforward to reach. Nearby, we also carry out external mastic in Kenley (1 mile south), Sanderstead (1 mile north-east), South Croydon (2 miles north), Hamsey Green (2 miles south-east) and Whyteleafe (2 miles south). Larger places within reach include London (12 miles north), City of Westminster (13 miles north), Marylebone (13 miles north), Kensington (13 miles north), St Pancras (14 miles north) and Shoreditch (13 miles north).
Around Riddlesdown
We work in homes and buildings around Riddlesdown Collegiate and Dollypers Hill and the streets around them. There’s a railway station in Riddlesdown itself: Riddlesdown station. A little further out are Croydon Airport Visitor Centre (2 miles north-west) and Purley War Memorial Hospital (1 mile north-west). The countryside around Riddlesdown includes Duppas Hill and Foxley Wood.
Towns and villages near Riddlesdown
More services for Riddlesdown
When it isn’t the sealant
Sealant isn’t the answer to every problem, and we’d rather say so up front. Sealant will not put right:
- Cracked brickwork or render that needs a builder or plasterer
- Failed render or damaged cladding panels
- Structural movement, which needs a surveyor or engineer
If in doubt, phone 0345 464 0079 or send us an email and we will say what we think before you book.
What we seal
- Façade panels
- Concrete & block
- Brickwork movement joints
- Copings & trims
- Joints between brick and frames
- Render & cladding joints
Keeping the joints in good condition
How long the joints last depends on use and care. Here’s what we suggest:
- Have failed joints looked at early
- Never let anyone fill a movement joint with mortar
- Keep high-pressure jets off the joints
- Keep water from gutters off the wall
Have a quick look at the joints each spring. Watch for splits, edges coming away or growth in the joint.
Gaps, plants or missing sealant in a joint are worth getting looked at. Early work is quicker and leaves a better finish.
Common problems we fix in Riddlesdown
Many joints fail because they were sealed too deep or with nothing behind them. Sealant bonded to three sides has nowhere to go and rips as the joint opens.
Look out for these signs:
- Cracked joints where brick meets render or frames
- Failed sealant between panels on a façade
- Hard, crazed mastic that has stopped moving
- Joints with sealant missing in places
As a London address, Riddlesdown can be tricky for parking: let us know about parking bays, permits or a driveway.
What your quote should include
- Are they insured?
- When the joint can take water or movement
- Which sealant they’ll use, and why
- What guarantee comes with the work
Quotes for external mastic in Riddlesdown
There’s no set price list, because jobs vary so much. The quote depends on:
- How much old sealant there is and how hard it is to remove
- How many areas need sealing
- Working hours on commercial sites
- Mould in or behind the old joints
The cost reflects the work involved, not guesswork. That’s why we ask about the job first and give you a clear price before any work starts.
Helping us quote
Photos by email are helpful but not essential. Try to tell us:
- The problem you’ve noticed
- Any access issues, like height or stairs
- The type of property
- The address or postcode of the job
Getting a quote is simple: let us know what needs doing and where. Photos by email help us understand the job.
Why act early in Riddlesdown
The longer a joint stays open, the more water the wall takes in. Wet masonry is more easily damaged by frost near the open joint, so the damage spreads beyond the joint. Damp from a failed joint spreads quietly in older London brickwork and timber, and by the time it shows on a wall or ceiling in Riddlesdown, the repair is bigger than the sealant job would have been.
We don’t show prices on the website, because each job is priced on what it involves. Call for a quick quote.
Why choose Mr Mastic in Riddlesdown
- Any old sealant cut out fully, not covered over
- Sealant colour chosen to suit
- We agree the colour with you first
- White, clear, grey or coloured to suit, where the product allows
Take a look at how sealant jobs are priced or customer reviews.
DIY sealant or a professional job?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
If you’re set on DIY, put the effort into 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.