Southampton · England
External Mastic in Southampton
Movement joints in Southampton need attention? We remove the old material, prepare the joints and seal them properly, with a one-year guarantee.
- Movement joints with cracked, split or missing sealant
- Panel joints letting water in
- Gaps where render, brick and frames meet
External mastic in Southampton
Joints between dissimilar materials, like brick against render or concrete against a steel frame, see movement from both sides. A flexible sealant bridges the two. Common call-outs are for weathered mastic that no longer stretches and moss and dirt in joints with no sealant left, on concrete & block, brickwork movement joints and façade panels.
A place the size of Southampton has buildings of every age, from older brick terraces to modern blocks with rendered or clad walls. Newer buildings rely on sealed movement joints, while older ones need their gutters, fascias and trims kept tight.
There’s a 12-month guarantee on every job.
- Where
- Southampton (SO19, SO16, SO15, SO18)
- Region
- Southampton
- Guarantee
- A year, on every job
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Leave it or put it right?
A failed movement joint lets water into the wall. Resealing early keeps the job to the joint itself, rather than the wall around it. For landlords in Southampton, failed sealant soon turns into tenant complaints about mould, damp or draughts. Sorting it between tenancies is easier than dealing with it mid-let.
A few things move the cost up or down: how much old sealant there is and how stubborn it is, any mould to treat, and whether the work is at height. We take all of that into account in your quote.
Why book with us
- ARBOMaster approved applicator
- Anti-fungal silicone where joints get wet
- Arbo and Everbuild products
- A 12-month guarantee on all work
Take a look at our cost guide and customer reviews.
Should I try it myself first?
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
What affects the cost of external mastic
Call for a quick quote. What matters most is:
- Access and height
- When we can work, for business premises
- How many rooms, windows or areas are involved
- Mould in or behind the old joints
The cost reflects the work involved, not guesswork. That is why we ask a few questions first and give you a clear quote before any work starts.
What we need to know
The more you tell us, the more accurate the quote. When you get in contact, it helps to mention:
- Photos by email, if that’s easy
- The rough size of the job
- Any previous sealing or DIY work
- What’s wrong with the joints now
Getting a quote is simple: tell us what needs doing and where and its rough size. Photos by email help us understand the job, and we will take it from there.
External mastic in Southampton: local notes
Southampton is close to the coast, where wind-driven rain is a fact of life and, nearer the shore, so is salt air. Both are hard on movement joints and outside wall joints, which can dry out and crack sooner where a building faces the weather. 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.
If you live in an older home near Saint Mary's, old and new materials meet at the roofline and walls, which is where sealant earns its keep. Letting a property close to St Denys station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies. For site and facilities teams at buildings such as Bevois Town Primary School, larger buildings have long runs of movement joint that eventually need resealing.
Southampton is in England. Whether you’re in the middle of Southampton or further out, external mastic is available for homes and businesses alike, from flats and houses to offices and hotels. 40 places in Southampton are on our list.
All of SO19, SO16, SO15 and SO18 is covered for external mastic. External mastic is available to properties on London Road, Marshall Square and Grosvenor Square and the roads around them. Southampton sits on or near the A27 and A33, so getting to you is simple. Neighbouring places we cover for external mastic include Inner Avenue (1 mile west), St Denys (1 mile north-east), Bitterne Manor (1 mile east), Portswood (1 mile north) and Northam (1 mile south-east). Further out, we also cover Maybush (3 miles west), Eling (4 miles west), Rownhams (3 miles north-west), Hounsdown (5 miles west), Nursling (4 miles north-west) and Hillyfields (3 miles west).
Near you in Southampton
Around Southampton, our work takes us to homes and buildings near Rockstone Place Park, The Hobbit pub and St Mary's Independent School. Southampton has its own railway station: St Denys station. Nearby you will also find Marlands Shopping Centre (1 mile south-west) and R J Mitchell Museum (0.9 miles south-west). For a walk, there’s Netley Common.
How to look after the new joints
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Have failed joints looked at early
- Point out the joints to other trades
- Ask before painting over external sealant
- Walk round the building once a year and look at the joints
Make sure anyone working on the wall later knows where the movement joints are. They must stay as flexible joints, never rendered or pointed over.
Small splits are the time to act. At that stage it’s a simple cut out and reseal.
Common questions in Southampton
Do you work for landlords with property near St Denys station?
Yes. We work for letting agents and landlords as well as householders. Just call 0345 464 0079 or drop us an email with the address and what needs doing, and we will send you a clear quote.
Do you cover Southampton for external mastic?
Yes. We work across London and the South East, and Southampton is part of that. You can phone 0345 464 0079 or send us an email and let us know what needs doing.
Can you do several jobs on one visit?
Yes, and it often makes sense. Combining jobs makes good use of the visit.
Do you do commercial work?
Yes, regularly. Larger jobs can be planned room by room or area by area to suit the site.
Do you use backing rod?
Backing rod controls the sealant depth and keeps it off the back of the joint. Then the sealant bonds to two faces and can move.
Will the new joint stand out?
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.
Which products do you use?
Each joint gets the product that suits it. Where it moves, gets wet or faces the weather makes a difference, and we will explain our choice.
Why is there a gap in my brick wall?
Walls move with heat, cold and moisture, so long walls have planned gaps to take that movement. The gap is sealed with a flexible sealant over backing rod.
Work for landlords, hotels and businesses
Hotels need rooms back in use, so we plan the work room by room. Hotel work is part of what we do, alongside homes and businesses.
Mouldy or split sealant often shows up at the end of a tenancy, and it’s quick to put right between tenancies. Several properties can be quoted together.
What the job involves on each surface
Concrete and blockwork
Wide joints in concrete need the depth controlling carefully. Backing rod sized to the joint sets it so the sealant is not too deep.
Copings and trims
Copings expand and contract through the day, so the joints need a sealant that stays flexible year round.
Towns and villages near Southampton
More services for Southampton
How the visit works
There is not much for you to do on the day. Point us to the joints and we’ll get on with it. The job generally takes a few hours to a few days, depending on the length of joint and the access, including the tidy-up. Jobs in a place the size of Southampton range from town-centre flats to offices and family homes. Whichever it is, tell us how to get in, where to park and where the work is.
- 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.
- We fit closed-cell backing rod to control the depth.
- We apply the sealant, tool it and check the whole run.
Getting ready for the visit
- On commercial sites, let us know about site rules
- Try not to wet indoor joints just before the visit
- Let us know if you’ve seen damp or leaks
How to get a quote
For a quote, ring 0345 464 0079 or drop us an email with the location and a short description of the problem. We’ll give you a clear price before any work starts.