Greater London · England
Thornton Heath External Mastic
Problem with your movement joints in Thornton Heath? We cut out the old, prepare the joints and apply the right sealant, with a 12-month guarantee.
- Cracked joints where brick meets render or frames
- Leaking joints around cladding and façade panels
- Brick movement joints where the sealant has split
Why deal with it now?
Running new sealant over the old bead rarely lasts. New sealant does not bond well to old, weathered sealant, so the old joint is cut out fully first. 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. Dealing with it early is far simpler for homes in Thornton Heath.
Leaving a failed joint normally makes the job bigger, not smaller. If you’re not sure whether it needs doing, call 0345 464 0079 or email us and we will give you an honest view and a quote.
Why book with us
- Sanitary silicone with an anti-fungal additive in wet areas
- White, clear, grey or coloured to suit, where the product allows
- A sealant colour to suit the surroundings
- One-year guarantee on every job
Take a look at what affects the cost and customer reviews.
About our external mastic in Thornton Heath
Movement joints let brickwork, render and cladding expand and shrink without cracking. The sealant in it has to stretch and squeeze for years, so once it splits or hardens, the joint stops working and water gets in. We work on concrete & block, façade panels and render & cladding joints, and the jobs we see most are failed sealant between panels on a façade and cracked joints where brick meets render or frames.
In London terraces and converted houses, gutters and walls are often shared with the house next door, so a leaking gutter joint or failed wall joint can affect more than one home. For a flat in Thornton Heath, check the lease for who looks after the outside.
The work is covered for a year after we finish. If anything is not right with it, phone 0345 464 0079 or email us.
- Where
- Thornton Heath (CR7, SW16, SE25)
- Region
- Greater London
- Cover
- 12 months on all our work
- Price
- Quoted before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Walls and rooflines in Thornton Heath
With historic houses such as Kingswood House (about 2.4 miles north-east) nearby, there’s older building stock in the area around Thornton Heath as well as newer homes. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth. Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
For an older house near a landmark such as Church of St Stephen, older walls, gutters and the joints where extensions meet them need a flexible sealant. Thornton Heath is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Thornton Heath is about 7 miles south of London, in Greater London. Our applicators cover external mastic for homes and businesses in Thornton Heath and nearby. 764 places in Greater London are on our list. You can also see our page for London, roughly 7 miles from Thornton Heath.
All of CR7, SW16 and SE25 is within our area for external mastic. External mastic is available to properties on Ena Road, Elm Road and Mayo Road and the roads around them. Thornton Heath sits on or near the A23 and A212, so getting to you is simple. Neighbouring places we cover for external mastic include Norbury (1 mile north), Pollards Hill (1 mile north), Mitcham (2 miles west), Hackbridge (2 miles west) and Eastfields (2 miles west). Larger places within reach include London (7 miles north), City of Westminster (8 miles north), Marylebone (8 miles north), Kensington (8 miles north-west), St Pancras (9 miles north) and Shoreditch (9 miles north).
Around Thornton Heath
Locally, jobs take us to homes and businesses close to The Archbishop Lanfranc School, Prince George pub and Grangewood Park, among other places. Thornton Heath has its own railway station: Thornton Heath station. A little further out are Centrale Croydon (1.7 miles south) and Croydon University Hospital (0.7 miles south). Green spaces nearby include Biggin Wood and Duppas Hill.
Also near Thornton Heath
Also in Thornton Heath
What affects the quote in Thornton Heath
Call for a quick quote. What matters most is:
- Whether the work is at height
- Any working-time requirements on site
- Mould in or behind the old joints
- How many areas need sealing
Homes and businesses are quoted the same way: how much there is to do, how we reach it and what it needs, along with when we can work on site. Ask us for a quote and we’ll go through it with you.
Asking for a quote
The more you tell us, the more accurate the quote. When you ask for a quote, tell us:
- What’s wrong with the joints now
- A few photos by email, if you can
- How many joints, rooms or windows are involved
- How we’d reach the joints
For a quick quote, get us on the phone, or send an email if you’d rather. Tell us about the joints that need doing and we will explain what’s involved before giving you a price.
How to look after the new joints
Simple care keeps the joints in good condition. Our advice:
- Keep water from gutters off the wall
- Don’t let climbing plants root in the sealant
- Look over the joints every year, ideally after winter
- Act on the first splits you see
Keep the joints clear of soil, plants and climbing growth. Anything that holds water against the joint wears it out sooner.
An open movement joint lets rain into the wall every time it pours. That can lead to damp patches, staining and frost damage which cost more to put right than the joint.
Surface by surface
Concrete and blockwork
Concrete faces can be dusty and porous, so cleaning and priming matter. We prime where the sealant needs it before the bead.
Joints between dissimilar materials
Joints where frames, sills or panels meet the wall are common leak points. The old joint is removed and a sealant that bonds to both sides goes in.
What we cannot put right
New sealant cannot fix everything, and we will tell you before work begins. Sealant will not put right:
- Adding movement joints to masonry that has none
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Cracks in the bricks or render themselves, away from the joints
If in doubt, ring 0345 464 0079 or send us an email and we’ll say what we think.
Joints and surfaces we work on
- Render & cladding joints
- Joints between brick and frames
- Façade panels
- Brickwork movement joints
- Copings & trims
- Concrete & block
The process
Every visit runs the same way: we check the joints, protect the area around them, carry out the job and clear up. Most jobs take anything from a few hours to several days, depending on the building. In a London area like Thornton Heath, the main things to plan are parking and access: let us know about parking, the floor we will be working on and any lift or shared entrance.
- 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.
- The joint faces are cleaned and primed where the sealant needs it.
- We push in closed-cell backing rod so the sealant is the right depth and bonds to the sides only.
- The new sealant, chosen to suit the brick or render, is applied and tooled to a neat finish.
How to prepare
- Tell us about access, such as stairs, a lift or high-level joints
- On commercial sites, let us know about site rules
- Tell us about any previous sealing or DIY attempts
Ask for a quote
For external mastic in Thornton Heath, phone 0345 464 0079 or drop us an email. Tell us what the problem is and where, and you will get a clear quote before we start.
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FAQs for Thornton Heath
Is parking a problem for a job in Thornton Heath?
Parking in Thornton Heath, 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.
Is Thornton Heath in your area for external mastic?
Yes. We work across London and the South East, and Thornton Heath is part of that. Just ring 0345 464 0079 or send us an email with a few details of the job.
Can you seal joints between render and window frames?
Yes. Different materials move at different rates, so a flexible sealant is needed where they meet. The sealant is matched to both sides.
Can tenants book the work?
We can work for tenants, landlords or agents. Just make sure your landlord agrees.
Will it make a mess?
Tidy work is part of the job. We protect what’s around the joints, and the area is left clean when we finish.
Why is there a gap in my brick wall?
Brickwork, render and cladding all move a little, and planned joints take up that movement. It’s closed with backing rod and a flexible sealant.
Where are you based?
Our base is in Crawley, West Sussex, and we work across South East England, London and Scotland.
Can you do several jobs on one visit?
Yes, and it often makes sense. Doing several areas at once is normally more efficient.
When to call us in Thornton Heath
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.
These are the problems we are asked about most:
- Joints where the bead has come unstuck
- Joints with sealant missing in places
- Gaps where render, brick and frames meet
- Plants rooting in failed movement joints
If you let a flat or house near Thornton Heath station, failed wall and movement joints let damp in, so they’re worth checking between tenancies.
What to look for in a quote
- How hidden problems are handled
- How the colour is chosen
- Is VAT in the price?
- What guarantee comes with the work