Greater London · England
Walworth External Mastic
We cover Walworth for sealing brickwork movement joints, render, cladding and façade joints. Old material cut out, joints cleaned and sealed neatly.
- Weeds or debris growing in open joints
- Leaking joints around cladding and façade panels
- Rain getting behind render or cladding at a joint
How we quote for external mastic
You will get a clear quote before work begins. It takes into account:
- How much old sealant there is and how hard it is to remove
- Any working-time requirements on site
- Any mould that needs treating
- Access and height
What it costs depends on the size of the job, how hard the old material is to remove and how easy the joints are to reach. You’ll have a clear quote before any work starts, so you know where you stand.
Helping us quote
What to tell us when you ask for a quote:
- How many joints, rooms or windows are involved
- Pictures of the joints, sent by email
- The problem you’ve noticed
- If someone has resealed it before
For a quick quote, get us on the phone, or email us if that’s easier. Describe what needs sealing and we will explain what’s involved before giving you a price.
About our external mastic in Walworth
A movement joint is only as good as its depth. Backing rod controls how deep the sealant goes and keeps it off the back of the joint, so it bonds to the two sides only and can stretch. If you are dealing with rain getting behind render or cladding at a joint and cracked joints where brick meets render or frames, we can put it right, whatever the surface.
Outside work in London starts with access: side passages, upper floors and where to park. For a home in Walworth, tell us how high the joints are and how to reach the back of the building.
You’re covered for a year from the day we finish. If anything is not right with it, phone 0345 464 0079 or send us an email.
- Location
- Walworth (SE1P, SE17, SE1)
- Wider area
- Greater London
- Cover
- A year, on every job
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Landlord and commercial work in Walworth
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
If you manage several properties in or around Walworth, several properties can be quoted together. Just tell us the addresses and what each one needs.
The process
Our applicators work methodically: protection first, then preparation, sealing and a tidy-up. For most jobs that takes a few hours to a few days, depending on the length of joint and the access, and the area is left clean. In Walworth, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- First we look over the joints with you, agree which to renew and talk through access.
- The old mastic and anything lodged in the joint is removed.
- 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.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
How to prepare
- Try not to wet indoor joints just before the visit
- Let us know if you’ve seen damp or leaks
- Clear the area around the work
Getting a quote
We quote each job on its own. Just ring 0345 464 0079 or send us an email with the details and send pictures if you have them.
Advice
Different surfaces, different methods
Render joints
The face of render can be soft, so a low-modulus sealant is kinder to the joint edges. We prime where the product needs it.
Brickwork movement joints
Brick movement joints are often mistaken for a missing mortar line. If that is happened, we rake it out and reseal it properly.
What we cannot put right
Before booking, it’s worth knowing the limits too:
- Structural movement, which needs a surveyor or engineer
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Cracking across the wall rather than at a joint
If you’re not sure, just ring 0345 464 0079 or send us an email and we’ll give you a straight answer before booking.
Joints and surfaces we work on
- Joints between brick and frames
- Render & cladding joints
- Brickwork movement joints
- Concrete & block
- Façade panels
- Copings & trims
Places near Walworth
Also in Walworth
External mastic in Walworth: local notes
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. Historic houses like Mansion House (about 1.6 miles north) are a reminder that the area around Walworth has older buildings as well as new. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
Homes close to Lady Margaret Church include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain. Rented homes near Elephant & Castle station change hands often, and split movement joints are easy to miss on a rental until damp shows inside.
Walworth is about 1 mile south of London, in Greater London. Anywhere in SE1P, our applicators can take on external mastic. Walworth is one of 764 places in Greater London where we work for external mastic.
Here we cover the SE1P, SE17 and SE1 postcode area for external mastic. If you need external mastic at a property on Mina Road, Ash Avenue and Angel Lane or anywhere close by, our applicators can take on the job. Close by, we work in London (1 mile north), Bermondsey (1 mile north-east), Camberwell (1 mile south), South Bermondsey (1 mile east) and Denmark Hill (2 miles south). Further out, we also cover City of Westminster (3 miles north-west), Marylebone (3 miles north-west), Kensington (5 miles west), St Pancras (3 miles north-west), Shoreditch (3 miles north) and Walthamstow (7 miles north-east).
Local landmarks in Walworth
We work in homes and buildings around University Academy of Engineering South Bank, Nursery Row Park and Lord Nelson pub. You’ll also find Lambeth Palace Library (1.3 miles north-west) and St Saviour's and St Olave's Church of England School (less than half a mile north). For rail, the closest station is Elephant & Castle station, about 0.5 miles north-west. Nearby you’ll also find Gabriel's Wharf (1.5 miles north-west) and The Walworth Clinic (within half a mile west). Not far away are Bellenden Road Nature Garden and St. James's Park Lake.
When to call us in Walworth
Using the wrong sealant is another common reason. A high-modulus or general-purpose sealant can be too rigid for a busy joint, so it pulls away from the edges.
Common reasons people contact us include:
- Moss and dirt in joints with no sealant left
- Old sealant gone brittle and cracked
- Gaps where render, brick and frames meet
- Brick movement joints where the sealant has split
If you look after a building such as Robert Browning Primary School, its movement joints, gutters and trims need looking after like any other building’s.
Questions to ask before booking
- How the surfaces are prepared before sealing
- What happens if the job turns out different
- The length of the guarantee
- Which colour the sealant will be
Your questions about external mastic in Walworth
Can you do external mastic in Walworth?
Yes. Our work covers London and the South East, and Walworth is part of that. Just phone 0345 464 0079 or send us an email with a few details of the job, and we will give you a clear quote.
Do you work for landlords with property near Elephant & Castle station?
Yes. We work for letting agents and landlords as well as homeowners. Just ring 0345 464 0079 or email us with the address and what needs doing, and we’ll give you a clear quote.
Can you seal over the old sealant?
No. The old sealant always comes out first.
What should I tell you?
The location, the problem and the rough size of the job. If you can, email a few pictures.
Do you remove the old sealant?
Always. Sealing over the old bead is the commonest cause of early failure, and it’s something we never do.
Should I try DIY first?
Sometimes. The key is preparation: remove all the old material and work on a clean, dry joint. If it does not work out, we can redo it.
What is backing rod for?
Backing rod goes into deeper joints as a matter of course. It controls the depth and stops the sealant bonding to the back.
Do I need to be at home?
Access is agreed with you when the job is booked. Indoors, that normally means someone at home.
Why it’s worth doing now in Walworth
It often makes sense to reseal all the failing joints on an elevation together. Joints of the same age tend to fail together and it means sorting access once. In a flat in Walworth, failed sealant seldom stays inside your own four walls: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
Instead of a standard rate, we price the job in front of us: the amount of work, the old material and the access. You will know the price before we begin.
Why choose Mr Mastic in Walworth
- More than 20 years in sealant work
- Neat joints and a tidy finish
- Anti-fungal silicone where joints get wet
- 4.9 on Google from 180+ five-star reviews
Read what affects the cost or customer reviews.