Greater London · England
Wandsworth External Mastic
External mastic for Wandsworth, by sealant specialists with 20+ years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Hard, crazed mastic that has stopped moving
- Joints where the bead has come unstuck
- Movement joints filled with mortar instead of sealant
Should I try it myself first?
If you do try it yourself, take your time over the preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
External mastic in Wandsworth, done properly
As ARBOMaster approved applicators, we choose exterior sealants to suit the joint and the surfaces. Porous or awkward surfaces are primed where the sealant needs it. Common call-outs are for plants rooting in failed movement joints and gaps where render, brick and frames meet, across joints between brick and frames, brickwork movement 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.
Your job is guaranteed for a year, as with all our work.
- Where
- Wandsworth (SW18, SW15, SW11)
- Region
- Greater London
- Cover
- A year, on every job
- Quotes
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Why act early in Wandsworth
Done well, a resealed joint is a neat, straight line that suits the wall. A rushed bead with no backing looks untidy and doesn’t last so it’s worth doing right. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and once it shows in Wandsworth, the repair is bigger than a sealant job.
Some things make a job bigger or smaller: the old material and how easily it comes out, whether mould needs treating, and whether we need extra access for height. Your quote takes all of that into account.
Why book with us
- White, clear, grey or coloured to suit, where the product allows
- Tidy, careful work
- Any old sealant cut out fully, not covered over
- A 12-month guarantee on all work
Read our cost guide or customer reviews.
How the visit works
All our tools and materials come with us in the van, so there’s nothing for you to buy. Once we have agreed what’s being done, we protect the area and start. Most jobs take anything from a few hours to several days, depending on the building. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. Mention any building rules, key holders or managing agents when you book.
- First, the joints are inspected and the access agreed.
- Every bit of old sealant and any mortar or debris is cut out.
- Joint faces are cleaned back and primed if the sealant needs it.
- Backing rod sized to the joint goes in to set the depth.
- The exterior sealant is applied, tooled and checked along its length.
Before we arrive
- Tell us if parking is tricky
- Try not to wet indoor joints just before the visit
- Mention any leaks or damp you’ve noticed
Getting a quote
For a quote, call 0345 464 0079 or email us and tell us where the job is and what the problem looks like. You’ll have a clear quote before we start.
Read more
Keeping the joints in good condition
Good habits help new joints last longer. Our tips:
- Keep soil, plants and ivy away from the joints
- Make sure movement joints aren’t pointed over
- Deal with leaking gutters that soak the joints below
- Show decorators and builders where the movement joints are
Look over the joints once a year, ideally after winter. Watch for splits, edges coming away or growth in the joint.
If you can see gaps, plants or bare sections in a joint, have it checked. Early work is quicker and leaves a better finish.
Also near Wandsworth
More services for Wandsworth
What affects the quote in Wandsworth
You’ll get a clear quote before we start. It takes into account:
- Working hours on commercial sites
- Whether there’s mould to deal with
- The size of the job
- How many rooms, windows or areas are involved
What it costs depends on the size of the job, how much old material has to come out and access to the work. You’ll have a clear quote before any work starts.
What we need to know
A few details help us give you an accurate quote. When you get in contact, it helps to mention:
- Whether it has been sealed before
- How many joints, rooms or windows are involved
- Whether it’s a home or a business
- The address or postcode of the job
For external mastic in Wandsworth, ring 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and you’ll get a clear quote before any work starts.
Signs you need external mastic in Wandsworth
Every building moves. Brickwork grows a little over the years, blockwork and concrete shrink, and all of it moves with heat and moisture. The sealant in the movement joints takes that strain.
Look out for these signs:
- Gaps where render, brick and frames meet
- Joints pointed up with cement by mistake
- Leaking joints around cladding and façade panels
- Joints with sealant missing in places
For landlords with property near Wandsworth Town station, split movement joints are easy to miss on a rental until damp shows inside.
Before booking anyone
- Are they insured?
- How long to leave it before use
- What preparation is included
- Whether all the old sealant comes out first
Landlords, agents and businesses in Wandsworth
For anyone letting property in or around Wandsworth, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs, and photos by email help.
Housing providers, facilities teams and property managers book us too in Wandsworth and across Greater London. We can quote a run of properties together, and we’re fully insured.
Walls and rooflines in Wandsworth
Historic houses like Fulham Palace (about 1.5 miles north-west) are a reminder that the area around Wandsworth 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. In terraces and conversions, gutters and walls are often shared with the neighbours, so it’s worth agreeing who is responsible before work starts.
If you look after a building such as St Anne's CofE Primary School, its movement joints, gutters and trims need looking after like any other building’s. If you live in an older home near St Anne's Church, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Wandsworth is about 3 miles south-west of Brompton, in Greater London. Wandsworth gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a one-year guarantee. Our area takes in 764 places across Greater London, large and small.
Jobs for external mastic in SW18, SW15 and SW11 works the same way as everywhere else we cover. External mastic is available to properties on Alma Road, Marl Road and Knoll Road and the roads around them. We also cover the places around Wandsworth: Southfields (1 mile south), Earlsfield (1 mile south), Hurlingham (1 mile north), Clapham Junction (1 mile north-east) and Battersea (1 mile north-east). Within a short drive, we also cover London (5 miles north-east), City of Westminster (4 miles north), Marylebone (5 miles north-east), Kensington (3 miles north), St Pancras (6 miles north-east) and Shoreditch (7 miles north-east).
What’s near Wandsworth
Typical jobs here are in homes near Ashcroft Technology Academy, Emanuel School and Spread Eagle pub. Wandsworth has its own railway station: Wandsworth Town station. Other landmarks nearby include Southside Wandsworth (under half a mile west) and Antique Breadboard Museum (1.4 miles north-west). Green spaces nearby include Battersea Park Lake and Henman Hill.
Common questions in Wandsworth
Do you work for landlords with property near Wandsworth Town station?
Yes, we work for landlords and letting agents. Just call 0345 464 0079 or send us an email and tell us about the property, and we’ll give you a clear price.
Is parking an issue for external mastic in Wandsworth?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. That way the visit can be planned around it.
Do the sealants smell?
That depends on the sealant. Some smell for a while, some hardly at all.
Can I add another job to the visit?
Yes. Just list everything you need and we’ll quote it together.
Do you come to Wandsworth?
Yes, we do. Our applicators work in Wandsworth.
How long does external mastic last?
That depends on the wall, the weather and the movement. Look for splits, hardening or edges coming away, and reseal at that point.
Do you do commercial work?
Yes. Hotels, offices and other businesses use us, and we’re fully insured.
Are you fully insured?
Yes. Full insurance covers our work.