Hampshire · England
External Mastic in Welborne
Specialist external mastic for Welborne: the right sealant, proper preparation and a neat finish. Call for a quick quote.
- Rain getting behind render or cladding at a joint
- Gaps where render, brick and frames meet
- Hard, crazed mastic that has stopped moving
FAQs for Welborne
Will you come out to Welborne?
Yes, smaller places are covered as well as towns. Our work covers London and the South East. Just mention lanes, gates or anything else about the route when you book.
Does living near the coast affect external mastic in Welborne?
Near the sea, outside joints face more wind, rain and salt than they would inland, so preparation and the right sealant matter all the more. Walls facing the sea are generally the first to need attention.
Is it OK to fill a movement joint with cement?
No. Mortar locks the joint solid, so the movement cracks the wall elsewhere. It needs a flexible sealant over backing rod.
Should I try DIY first?
Some simple jobs can be done by a careful DIYer. Most DIY failures come from sealing over old material, wet joints or too much sealant.
How long does the job take?
It depends on the size of the job, but most jobs take a few hours to a few days, depending on the length of joint and the access. We’ll give you a better idea when we quote.
Why is there a gap in my brick wall?
It’s a deliberate gap that lets the wall expand and contract without cracking. It’s sealed with a flexible sealant, not mortar.
Why do you put foam in the joint first?
Backing rod controls the sealant depth and keeps it off the back of the joint. That way it bonds to the two sides only and can stretch.
When is the sealant fully cured?
It depends on the product and the conditions. We tell you how long to leave it before we go.
About our external mastic in Welborne
A movement joint is a deliberate break that lets a wall expand and contract. The sealant in it has to stretch and squeeze for years, and when it fails, the wall takes the strain and water finds a way in. If you have joints with sealant missing in places and gaps where render, brick and frames meet, we can put it right, whatever the surface.
External sealant needs dry, clean surfaces, so work around Welborne is planned for dry weather. Tell us about access to all sides of the building, including outbuildings and garages.
The work is covered for a year after we finish. If anything isn’t right with it, phone 0345 464 0079 or email us.
- Place
- Welborne (PO17)
- Wider area
- Hampshire
- Cover
- One year on every job
- Quotes
- A clear price before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
When something else is needed
Before booking, it’s worth knowing the limits:
- Movement that is more than a sealant joint can take
- Cracked brickwork or render that needs a builder or plasterer
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
If in doubt, phone 0345 464 0079 or send us an email and we’ll say what we think before booking.
Where we work in Welborne
- Copings & trims
- Render & cladding joints
- Brickwork movement joints
- Façade panels
- Joints between brick and frames
- Concrete & block
Why deal with it now?
A failed movement joint lets water into the wall. Dealing with it early keeps the repair to the joint, instead of the wall and finishes around it. Around Welborne, older homes often have timber in their floors and frames, where water from a failed joint can cause rot if it’s left.
What it costs depends on how much there is to do, how hard the old material is to remove and how easy the joints are to reach. You will have a clear quote before any work starts, so you know where you stand.
What you get with us
- Anti-fungal sanitary silicone in wet areas
- Experience in homes, commercial sites and hotels
- A sealant colour to suit the surroundings
- Quality sealants from Arbo and Everbuild
Read what affects the cost and what customers say.
How the job changes by surface
Render joints
Cracks along render joints let water in behind the coat. A sound joint keeps the render dry behind.
Copings and trims
A failed coping joint lets water into the top of the wall. Resealing them is a small job that protects a lot.
The process
Before we leave, we go over the finished joints with you and tell you how long to leave it. The visit itself generally takes a few hours for a handful of joints, longer for a whole elevation, depending on how much there is to do. Somewhere like Welborne needs a little journey planning: tell us about narrow lanes, gates, long drives and where we can park. We bring what the job needs, so it can be finished in one trip where possible.
- 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.
Before we arrive
- Plan for the work area to be out of bounds to pets and children
- Let us know about earlier repairs to the joints
- Clear the area around the work
Getting a quote
Every job is quoted individually. Simply call 0345 464 0079 or send us an email and describe the job, and pictures are welcome.
Related advice
Places near Welborne
More services for Welborne
Work for landlords, hotels and businesses
Landlords and letting agents in Welborne can book us as well as homeowners. Sealant work between tenants is a simple way to keep a property in good order before the next move-in.
For anyone letting property in or around Welborne, several properties can be quoted together. Send us the addresses and the work at each.
Welborne buildings and the weather
Welborne 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. 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 look after a building such as The Henry Cort Community College, its movement joints, gutters and trims need looking after like any other building’s. For an older house near a landmark such as Church of St Francis, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Welborne is about 2 miles north of Fareham, in Hampshire. Every kind of property in Welborne can book us for external mastic, old or new, large or small. The work is guaranteed for a year. 683 places in Hampshire are on our list, large and small. We also work in Portsmouth, about 7 miles from Welborne.
Work in PO17 is quoted and booked the same way as anywhere else. Nearby, we also carry out external mastic in Crockerhill (1 mile east), Wickham Common (1 mile north-east), North Fareham (1 mile south-east), Hundred Acres (2 miles north-east) and Fareham (2 miles south). Within a short drive, we also cover Winchester (13 miles north-west), Gosport (6 miles south), Havant (9 miles east), Eastleigh (9 miles north-west), Horndean (8 miles east) and Totton (14 miles west).
What’s near Welborne
We work in homes and buildings around The Miners Arms and the streets around them. Welborne’s nearest station is Fareham station, about 1.9 miles south. A little further out are Carron Row Farm Museum (2.4 miles south-west) and Portchester Castle (4.5 miles south-east). The countryside around Welborne includes Portsdown Hill and Swanwick Lakes.
How we quote for external mastic
The price is agreed before any work begins. It takes into account:
- Any working-time requirements on site
- Which sealant suits the joint
- The number and length of the joints
- How many rooms, windows or areas are involved
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether we need extra access for height. Your quote takes all of that into account.
Helping us quote
When you call or email, it’s useful to know:
- How many joints, rooms or windows are involved
- Any previous sealing or DIY work
- The address or postcode of the job
- Photos by email, if that’s easy
Call for a quick quote, or send an email if you’d rather. Tell us about the joints that need doing and we’ll explain what’s involved before giving you a price.
Do you need external mastic in Welborne?
Sometimes a movement joint was filled with mortar or a rigid filler, often by someone who didn’t know what it was for. The joint cannot move, so the wall cracks somewhere else instead.
These are the problems we’re asked about most:
- Failed seals between different materials
- Plants rooting in failed movement joints
- Joints where the bead has come unstuck
- Old sealant gone brittle and cracked
Letting a property close to Fareham station? Then split movement joints are easy to miss on a rental until damp shows inside.
Questions to ask before booking
- Is the old sealant removed completely?
- Who turns up on the day
- How the surfaces are prepared before sealing
- How the colour is chosen