Greater London · England
Selsdon External Mastic
Sealing brickwork movement joints, render, cladding and façade joints in Selsdon, with a 12-month guarantee on every job. Ask us for a quote.
- Plants rooting in failed movement joints
- Failed seals between different materials
- Joints with sealant missing in places
How the job changes by surface
Brickwork movement joints
Brick walls have vertical movement joints to absorb expansion. They’re resealed over backing rod with a low-modulus sealant in a colour to suit the brick.
Copings and trims
Metal and stone copings both move with temperature, so the joints need a sealant that stays flexible in all weathers.
External mastic for homes and businesses in Selsdon
Where two different materials meet, such as brick and render or blockwork and metal, they move at different rates. A flexible exterior sealant takes up that movement. We work on façade panels, joints between brick and frames and brickwork movement joints, and the jobs we see most are gaps where render, brick and frames meet and plants rooting in failed movement joints. Whether you’re looking for a local mastic man, a sealant applicator or a sealant contractor in Selsdon, that’s what we do.
Newer London blocks are built with movement joints in brick and render, and with cladding joints sealed with mastic. 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.
We stand behind the work with a one-year guarantee.
- Where
- Selsdon (CR2, CR0)
- Wider area
- Greater London
- Cover
- One year on every job
- Quote
- A clear quote up front
- Telephone
- 07833 053749
- Last updated
- 26 October 2026
Nearby places to Selsdon
Other services in Selsdon
What we can’t put right
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
- Loose or hollow render, which needs re-rendering
- Movement that is more than a sealant joint can take
If you’re not sure, just phone 07833 053749 or send us an email and we’ll give you a straight answer before booking.
Joints and surfaces we work on
- Render & cladding joints
- Joints between brick and frames
- Brickwork movement joints
- Copings & trims
- Façade panels
- Concrete & block
Your questions about external mastic in Selsdon
Can parking be tricky for a visit in Selsdon?
Parking in Selsdon, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly.
Do you cover Selsdon for external mastic?
Yes. Our work covers London and the South East, and Selsdon is part of that. You can phone 07833 053749 or email us and tell us what needs doing.
Can new sealant go over the old?
No, it will not last. It may look fine at first, but the new bead soon lifts. The old sealant has to come out completely.
Can you reach joints on upper floors?
That depends on how high the joints are and the ground below. Low-level joints are straightforward; for higher work, tell us about the building and we’ll confirm what’s needed.
Are you insured?
Yes. We are fully insured.
How do I get a quote for external mastic in Selsdon?
There’s no set price, as it depends on the job: how much there is, what’s there now, how we reach it and what it needs. We agree the price before any work begins.
What’s an expansion joint in brickwork?
Brickwork, render and cladding all move a little, and planned joints take up that movement. The gap is sealed with a flexible sealant over backing rod.
Is it worth trying it myself?
It depends on the job. High-level, external movement and fire-rated joints are professional jobs, while a short indoor joint may be within reach.
Looking after it afterwards
Simple care keeps the joints in good condition. Our advice:
- Have failed joints looked at early
- Avoid pressure-washing directly into sealant joints
- Tell anyone working on the walls about the movement joints
- Keep movement joints as flexible joints, not mortar
Follow the cure time we give you before the joint is knocked or disturbed. The surface skins over quickly, but full cure takes longer.
Gaps, plants or missing sealant in a joint are worth getting looked at. Earlier resealing means a smaller job and a better result.
How it works
We bring everything the job needs with us, so you don’t need to buy or prepare anything. Once we have agreed what’s being done, we protect the area and start. It normally takes anything from a few hours to several days, depending on the building. In Selsdon, flats, stairs and shared entrances are part of the routine. Mention any building rules, key holders or managing agents when you book.
- We inspect the joints and agree which need resealing and how they’ll be reached.
- Old sealant and any debris are cut and raked out.
- 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.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
Preparing for the visit
- Let us know if you’ve seen damp or leaks
- Tell us about access, such as stairs, a lift or high-level joints
- Plan for the work area to be out of bounds to pets and children
Getting a quote
We quote each job on its own. Just ring 07833 053749 or send us an email with the details and send pictures if you have them.
Advice
DIY sealant or a professional job?
The biggest DIY mistake is sealing over old sealant. New silicone won’t bond to old, so it lifts and traps water and mould underneath. Everything old must be removed first.
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
What we are called out for in Selsdon
Joints sealed without backing rod, or far too deep, rarely last. Sealant bonded to three sides has nowhere to go and rips as the joint opens.
The most common problems we see are:
- Movement joints with cracked, split or missing sealant
- Damp patches traced to an open external joint
- Plants rooting in failed movement joints
- Failed seals between different materials
As a London address, Selsdon can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
Before booking anyone
- Whether all the old sealant comes out first
- Whether VAT is included
- What happens if the job turns out different
- Which sealant they’ll use, and why
Why it’s worth doing now in Selsdon
Mortar or ordinary filler might look like a quick way to close an open joint, but it stops the joint moving. The wall then cracks somewhere else. A flexible sealant over backing rod is what the joint needs. Damp from a failed joint spreads quietly in older London brickwork and timber, and once it shows in Selsdon, the repair is bigger than a sealant job.
Every job is a little different, so we quote each one individually. The number of joints, how easy they are to reach and the sealant needed all make a difference.
Why us?
- A choice of colours where the product allows
- Fully insured
- Over 20 years’ experience
- You choose the colour before work begins
See what affects the cost and what customers say.
Selsdon buildings and the weather
With historic houses such as Addington Palace (about 1 mile north-east) nearby, there’s older building stock in the area around Selsdon as well as newer homes. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth. London terraces and converted houses often share gutters, downpipes and walls, so check who is responsible for the outside before booking.
For landlords with property near Sanderstead station, failed wall and movement joints let damp in, so they’re worth checking between tenancies. In the older streets around St Francis, the joints between older walls, newer extensions and the roofline need a sealant that can move.
Selsdon is about 2 miles south-east of Croydon, in Greater London. Whether you’re in the middle of Selsdon or further out, we cover external mastic for every kind of property. We cover 786 towns and villages across Greater London, from the larger towns to small villages.
We cover every part of the CR2 and CR0 postcode area for external mastic and the streets around it. External mastic is available to properties on York Road, Byron Road and Abbey Road and the roads around them. We also cover the places around Selsdon: Forestdale (1 mile east), Addington (1 mile north-east), Sanderstead (1 mile south-west), Coombe (1 mile north-west) and Farleigh (2 miles south-east). Larger places within reach include London (11 miles north), City of Westminster (12 miles north), Marylebone (13 miles north), Kensington (12 miles north-west), St Pancras (13 miles north) and Shoreditch (13 miles north).
What’s near Selsdon
Typical jobs here are in homes near Royal Russell School, The Sir Julian Huxley pub and The Quest Academy, among other places. Selsdon’s nearest station is Sanderstead station, about 1.7 miles west. Well-known places in the area include St George's Walk (2.7 miles north-west) and Croydon Airport Visitor Centre (2.9 miles west). Open spaces near Selsdon include Duppas Hill and Bramley Bank.