Greater London · England
External & façade joints in Sundridge, Greater London
External mastic for Sundridge, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Cracked joints where brick meets render or frames
- Brick movement joints where the sealant has split
- Sealant pulling away from one side of the joint
About our external mastic in Sundridge
Failed sealant is cut out, the depth set with closed-cell backing rod, and the joint resealed with a low-modulus sealant made for outside. We pick a colour that sits well with the wall so the line blends in. Typical jobs include weathered mastic that no longer stretches and joints where the bead has come unstuck, on joints between brick and frames, render & cladding joints and copings & trims.
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.
All our work is covered by our 12-month guarantee, wherever you are in Greater London.
- Location
- Sundridge (BR1, BR7, BR2)
- Region
- Greater London
- Cover
- 12 months on all our work
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
External mastic in Sundridge: local notes
In terraces and conversions, gutters and walls are often shared with the neighbours, so check who is responsible for the outside before booking. London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
If you live in an older home near St Andrew, older walls, gutters and the joints where extensions meet them need a flexible sealant. Rented homes near Sundridge Park station change hands often, and failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Sundridge is about 1 mile north-east of Bromley, in Greater London. Anywhere in BR1, we cover external mastic for homes and businesses. Across Greater London, we cover 764 places, and Sundridge is one of them. For nearby work, see our London page (8 miles or so).
Work in BR1, BR7 and BR2 is quoted and booked the same way as anywhere else. You’ll find streets such as Hawes Road, North Road and Croft Road, all of which we cover. We also cover the places around Sundridge: Plaistow (1 mile west), Grove Park (1 mile north), Downham (1 mile north-west), Chinbrook (1 mile north) and Elmstead (1 mile east). Within a short drive, we also cover London (8 miles north-west), City of Westminster (10 miles north-west), Marylebone (10 miles north-west), Kensington (11 miles north-west), St Pancras (10 miles north-west) and Shoreditch (9 miles north-west).
Landmarks near Sundridge
Around Sundridge, our work takes us to homes and buildings near Elmstead Wood, Holy Trinity College Bromley and Haberdashers' Aske's Knights Academy. There’s a railway station in Sundridge itself: Sundridge Park station. A little further out are Bromley Hospital (1.4 miles south) and Greenwich Castle (4.4 miles north). Open spaces near Sundridge include Summer Hill and Downham Woodland Walk.
What the job involves on each surface
Concrete and blockwork
Blockwork and concrete shrink over time and move with the seasons. We reseal their joints with backing rod and a flexible product.
Joints between dissimilar materials
Joints where frames, sills or panels meet the wall are common leak points. We cut out the old sealant and reseal with a product suited to both surfaces.
What affects the cost of external mastic
The price is agreed before any work begins. It’s based on:
- Which sealant suits the joint
- Access and height
- Any working-time requirements on site
- How many rooms, windows or areas are involved
The cost depends on how much there is to do, how hard the old material is to remove and access to the work. We give a clear quote before any work starts, so you know where you stand.
What we need to know
Before you ask for a quote, have a think about:
- Roughly how big the job is
- A few pictures by email, if you can
- Any access issues, like height or stairs
- The type of property
For external mastic in Sundridge, phone 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and we will agree the price before any work begins.
When to call us in Sundridge
Some movement joints have been pointed up with mortar. The joint cannot move, so the wall cracks somewhere else instead.
Keep an eye out for any of the following:
- Failed sealant between panels on a façade
- Water getting into walls through failed joints
- Joints pointed up with cement by mistake
- Plants rooting in failed movement joints
Managing a site like St Joseph's Catholic Primary School? Then its movement joints, gutters and trims need looking after like any other building’s.
What your quote should include
- How much experience the applicator has
- Whether they seal over old material or remove it
- What insurance they hold
- What happens if they find a problem under the old sealant
Looking after it afterwards
A little care helps the new joints last. Our advice:
- Leave the joints unpainted unless we have said otherwise
- Get split or bare joints resealed while the damage is small
- Never let anyone fill a movement joint with mortar
- Point out the joints to other trades
Keep the joints clear of soil, plants and climbing growth. Anything that holds water against the joint wears it out sooner.
Leave a failed movement joint and water keeps getting into the wall. Over time it can mean damp inside, stained render or frost-damaged brick.
When something else is needed
Honest advice matters more to us than a booking, so here’s what new sealant will not do:
- Cutting new joints into brickwork, which is building work rather than sealant work
- Subsidence or other structural problems
- Cracks in the bricks or render themselves, away from the joints
If you are not sure, just phone 0345 464 0079 or email us and we’ll give you a straight answer before booking.
Joints and surfaces we work on
- Façade panels
- Brickwork movement joints
- Copings & trims
- Concrete & block
- Joints between brick and frames
- Render & cladding joints
Common questions in Sundridge
Do you work for landlords with property near Sundridge Park station?
Yes. We work for letting agents and landlords as well as householders, and several properties can go on one quote. Just call 0345 464 0079 or send us an email with the address and what needs doing, and we’ll give you a clear price.
Is Sundridge in your area for external mastic?
Yes. We work across London and the South East, and Sundridge is part of that. You can phone 0345 464 0079 or drop us an email and let us know what needs doing, and we will send you a clear quote.
What does external mastic cost?
Every job is different, so each one gets its own quote. For a quick quote, phone 0345 464 0079 or drop us an email with a short description of the job.
What sealant do you use?
It depends on the joint: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. Brands we use include Arbo and Everbuild.
Is it messy?
No. We protect the surfaces around the joints, and we clear up the old sealant and our materials before we leave.
Where is Mr Mastic based?
Mr Mastic is based in Crawley. We cover Sundridge and the rest of Greater London, along with the rest of our area.
When is the sealant fully cured?
It depends on the product and the temperature. Before we leave, we will tell you the cure time.
What’s an expansion joint in brickwork?
Most straight vertical gaps in brickwork are movement joints. It gives the wall room to move, and it should be sealed with a flexible sealant.
How it works
At the end, we look at the finished work together. The work normally takes anything from a few hours to several days, depending on the building, depending on how much there is to do. For a job in Sundridge, parking and access are the things to plan: let us know about parking, the floor we will be working on and any lift or shared entrance.
- We look at every joint and agree a colour to suit the wall.
- Failed sealant is removed back to clean, sound faces.
- Backing rod goes in so the sealant can stretch between the two faces.
- Primer is applied wherever the sealant needs it.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
How to prepare
- Let us know if you’ve seen damp or leaks
- On commercial sites, let us know about site rules
- Mention any tricky access
Getting a quote
It all starts with a short chat. Tell us what’s wrong, where it is and how much there is, and we’ll explain how we’d tackle it. When it suits you, phone 0345 464 0079 or email us.
Advice
Other services in Sundridge
Why deal with it now?
Mortar or ordinary filler might look like a quick way to close an open joint, but it locks the joint solid. The wall then cracks somewhere else. The correct repair is a flexible sealant with the right backing. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and by the time it shows on a wall or ceiling in Sundridge, the repair is bigger than the sealant job would have been.
Rather than a set price list, we look at what your job involves: the amount of work, the old material and the access. You will know the price before we begin.
Why choose Mr Mastic in Sundridge
- White, clear, grey or another colour, product permitting
- More than 20 years in sealant work
- Colour agreed with you before we start
- Any old sealant cut out fully, not covered over
See our cost guide and what customers say.