Greater London · England
Elmers End External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for Elmers End, backed by a 12-month guarantee. Call for a quick quote.
- Failed sealant between panels on a façade
- Old sealant gone brittle and cracked
- Joints where the bead has come unstuck
External mastic for homes and businesses in Elmers End
A movement joint is only as good as its depth. Closed-cell backing rod sets the depth and stops the sealant sticking to the back, so it bonds to the two sides only and can stretch. We work on joints between brick and frames, façade panels and concrete & block, and common reasons people get in touch are gaps where render, brick and frames meet and weeds or debris growing in open joints.
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.
Our work is backed for twelve months.
- Location
- Elmers End (BR3, SE25, CR0)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Keeping the joints in good condition
Once the sealant has cured, a few habits help it last:
- Act on the first splits you see
- Make sure movement joints aren’t pointed over
- Keep high-pressure jets off the joints
- Fix overflowing gutters above sealed joints
Don’t let soil, plants or ivy build up against the new joints. Damp material against the sealant shortens its life.
If you can see gaps, plants or bare sections in a joint, have it checked. Earlier resealing means a smaller job and a better result.
What affects the cost of external mastic
Your quote is based on your job. We take into account:
- Whether the work is at height
- Working hours on commercial sites
- How many rooms, windows or areas are involved
- The product the joint needs
The cost reflects the work involved, not guesswork. That’s why we ask a few questions first and send you a clear quote before work begins.
What we need to know
To make quoting easier, please include:
- What the problem is, such as mould, gaps, leaks or cracking
- How many joints, rooms or windows are involved
- Where the job is, and your postcode
- A few photos by email, if you can
To get a quote, ring 0345 464 0079 or send us an email and tell us where the job is and what the problem looks like. You’ll have a clear quote before any work starts.
What happens if it’s left?
An open joint keeps letting water into the wall with every downpour. Wet masonry is more easily damaged by frost, so the damage spreads beyond the joint. In a London flat, a failed joint rarely stays your problem alone: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
There are no prices on our website, because the cost depends so much on the job itself. Call for a quick quote and we’ll talk you through it.
Why us?
- A choice of colours where the product allows
- More than 20 years in sealant work
- Every job guaranteed for a year
- Anti-fungal sanitary silicone in wet areas
Read what affects the cost and our reviews.
Surface by 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.
Render joints
Rendered walls have joints at beads, openings and changes of material. We reseal them with a flexible exterior sealant that suits the render colour.
What we cannot put right
A few problems are outside what sealant work can do:
- Adding movement joints to masonry that has none
- Cracking across the wall rather than at a joint
- Loose or hollow render, which needs re-rendering
If you are not sure, just call 0345 464 0079 or drop us an email and we’ll give you a straight answer.
Where we work in Elmers End
- Copings & trims
- Brickwork movement joints
- Façade panels
- Joints between brick and frames
- Concrete & block
- Render & cladding joints
Nearby places to Elmers End
Other services in Elmers End
The process
We keep the work tidy and contained to the area we’re working on. The job normally takes anything from a few hours to several days, depending on the building, and we tell you how long to leave it before we go. In Elmers End, as in most of London, parking needs a little planning. A visitor permit or a nearby bay makes the visit run more smoothly.
- We start by checking each joint, agreeing the ones to redo and how we will reach them.
- The old mastic and anything lodged in the joint is removed.
- We clean both faces of the joint and prime them where the product calls for it.
- Closed-cell backing rod is fitted to set the depth and stop three-sided bonding.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
Preparing for the visit
- Tell us if parking is tricky
- Mention if the joints have been sealed before
- Let us know about stairs, lifts or work at height
How to get a quote
Asking for a quote is easy: let us know the job and the location, and roughly how big it is. Photos by email help us understand the job, and we will take it from there.
Advice
Should I try it myself first?
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
If you do try it yourself, take your time over the 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.
Walls and rooflines in Elmers End
London terraces and converted houses often share gutters, downpipes and walls, so check who is responsible for the outside before booking. Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
In the older streets around St James's Church, an extension built onto an older house moves differently, and the joint between them takes the strain. Schools such as Marian Vian Primary School are buildings too, and its movement joints, gutters and trims need looking after like any other building’s. For landlords with property near Elmers End station, outside joints that have cracked can let damp into a rental, so check them between lets.
Elmers End is about 1 mile south-west of Beckenham, in Greater London. Every kind of property in Elmers End is covered for external mastic, old or new, large or small. Every job comes with our 12-month guarantee. Elmers End is one of 764 towns and villages in Greater London where we work. We also work in London, around 7 miles away.
Work in BR3, SE25 and CR0 works the same way as everywhere else we cover. We cover properties on Love Lane, Long Lane and Beck Lane. If you’re just outside Elmers End, we cover Woodside (1 mile south-west), Ashburton (1 mile south-west), Selhurst (1 mile west), South Norwood (1 mile west) and Monks Orchard (1 mile south). Further out, we also cover London (7 miles north), City of Westminster (9 miles north-west), Marylebone (9 miles north-west), Kensington (10 miles north-west), St Pancras (9 miles north) and Shoreditch (9 miles north).
Local landmarks in Elmers End
Around Elmers End, our work takes us to homes and buildings near The Mitre pub, Winsford Gardens and Oasis Academy Arena, among other places. There’s a railway station in Elmers End itself: Elmers End station. A little further out are Beckenham Beacon (1 mile north-east) and Whitgift Centre (2.5 miles south-west). Not far away are Dulwich Upper Wood and Duppas Hill.
Common questions in Elmers End
Can parking be tricky for a visit in Elmers End?
Parking in Elmers End, as in most of London, takes a little planning: a visitor permit or a bay close to the door helps a lot.
Do you cover Elmers End for external mastic?
Yes. We work across London and the South East, and Elmers End is part of that. Just phone 0345 464 0079 or email us with a few details of the job, and we’ll give you a clear price.
Can you match the colour of my brickwork?
There’s a good range of exterior colours, including greys, browns, whites and stone tones. We pick the one that suits your wall best so the joint does not draw the eye.
Will the old sealant be removed?
Yes, always, and completely. New silicone doesn’t stick to old silicone, so the joint is cleaned back first.
When will the joints need doing again?
It varies with how exposed the wall is and how much the joint moves. Look for splits, hardening or edges coming away.
Where is Mr Mastic based?
We are based in Crawley, and we cover South East England, London and all of Scotland.
Is it OK to fill a movement joint with cement?
No. Cement or mortar cannot stretch and the joint fails. Where a joint has been mortared, it can often be raked out and sealed properly.
Do you work for hotels and businesses?
Yes. We can plan bigger jobs in stages.