Isle of Wight · England
External Mastic in Dunsbury
Sealing brickwork movement joints, render, cladding and façade joints for homeowners, landlords and businesses in Dunsbury. Fully insured, ARBOMaster approved and guaranteed for a year.
- Movement joints filled with mortar instead of sealant
- Sealant pulling away from one side of the joint
- Old sealant gone brittle and cracked
Questions from Dunsbury
Can you do external mastic in Dunsbury?
Yes, Dunsbury is within the area we cover. We work across London and the South East. You can phone 0345 464 0079 or email us and tell us what needs doing, and we’ll give you a clear quote.
Does living near the coast affect external mastic in Dunsbury?
Coastal weather is harder on outside sealant: there’s more wind-driven rain and, closer to the shore, salt in the air. The right product, a clean joint and the right depth all help it cope.
Should I point up the gap in my brickwork?
No. A mortar-filled joint can’t move, so the wall cracks somewhere else instead. Use a flexible sealant with backing rod.
What is backing rod for?
Backing rod goes into deeper joints as a matter of course. It sets the sealant depth and prevents three-sided bonding, so the joint can move.
Do you have insurance?
Yes. We are fully insured, and we can confirm the details when we quote.
What’s an expansion joint in brickwork?
It’s a deliberate gap that lets the wall expand and contract without cracking. It should be filled with flexible sealant, never mortar.
Will the new joint stand out?
Exterior sealants are made in a range of colours, from greys and browns to whites and stone shades. We pick the one that suits your wall best so it does not stand out.
Where is Mr Mastic based?
Our base is Crawley. Our area covers South East England, London and Scotland.
About our external mastic in Dunsbury
For buildings in Dunsbury, we reseal external joints of all kinds, from brick movement joints to cladding panels. The preparation is the same whatever the wall: clean joint faces and the right depth. We work on joints between brick and frames, façade panels and render & cladding joints, and people most often call us about old sealant gone brittle and cracked and rigid filler in a joint that should flex.
Somewhere as small as Dunsbury, homes and farm buildings often face open ground, so walls and rooflines take the full force of wind and rain. Joints on those walls need a sealant that moves with the building and stays in place.
Your job is guaranteed for a year, as with all our work.
- Place
- Dunsbury (PO30)
- Region
- Isle of Wight
- Cover
- 12 months on all our work
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
When it isn’t the sealant
Sealant is not the answer to every problem, and we’d rather say so up front. Sealant won’t put right:
- Structural movement, which needs a surveyor or engineer
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Loose or hollow render, which needs re-rendering
If in doubt, call 0345 464 0079 or send us an email and we’ll say what we think before you book.
Joints and surfaces we work on
- Brickwork movement joints
- Joints between brick and frames
- Façade panels
- Render & cladding joints
- Copings & trims
- Concrete & block
Outside joints around Dunsbury
Dunsbury is within about 1 mile of the coast, where wind-driven rain is a fact of life and, nearer the shore, so is salt air. That’s hard on movement joints and outside wall joints, especially on the side facing the sea. With historic houses such as Mottistone Manor (about 1.2 miles east) nearby, there’s older building stock in the area around Dunsbury as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
In and around Dunsbury, as anywhere, good external mastic starts with a clean, dry, properly prepared joint.
Dunsbury is about 7 miles south-west of Newport, in the Isle of Wight. Every kind of property in Dunsbury is covered for external mastic, old or new, large or small. Every job comes with our 12-month guarantee. Our the Isle of Wight coverage runs to 125 places, Dunsbury among them. For nearby work, see our Southampton page (18 miles or so).
Our applicators cover all of the PO30 postcode area for external mastic. Neighbouring places we cover for external mastic include Brook (1 mile south), Hulverstone (1 mile south-east), Brookgreen (1 mile south-east), Shalcombe (1 mile north-east) and Chilton Green (2 miles south-east). We also work in nearby towns such as Newport (7 miles north-east), Ryde (14 miles east), Cowes (9 miles north-east), Sandown (13 miles east), Shanklin (12 miles east) and Ventnor (12 miles east). If you are somewhere remote, a little more planning is needed, so mention it when you ask for a quote.
What’s near Dunsbury
Well-known places in the area include Yarmouth Castle (3.9 miles north-west) and Calbourne Water Mill And Rural Museum (2.3 miles north-east). Not far away are Westover Down.
Landlord and commercial work in Dunsbury
Failed sealant is one of the commonest items on a check-out report, and it’s easy to sort out between tenants. We can quote for more than one property at once.
Hotels need rooms back in use, so the work can be planned room by room. Hotel work is part of what we do, alongside homes and businesses.
Leave it or put it right?
Pointing a movement joint with mortar might seem a neat fix, but it stops the joint moving. The wall then cracks somewhere else. A flexible sealant over backing rod is what the joint needs. In a small place like Dunsbury, homes can be exposed to wind and rain, which finds any gap, and older walls, once damp, take a long time to dry.
We do not show prices on the website, because the cost depends so much on the job itself. For a quick quote, please call 0345 464 0079 or send us an email.
Why us?
- We leave the area clean and tidy
- A 12-month guarantee on all work
- We agree the colour with you first
- Quality sealants from Arbo and Everbuild
Read how sealant jobs are priced and customer reviews.
Places near Dunsbury
What else we do in Dunsbury
How the job changes by surface
Render joints
The face of render can be soft, so a sealant that stretches easily protects the edges. We prime where the product needs it.
Cladding and façade panels
If the façade has a specified sealant, that is what we use. Send us any details you have about the façade.
The process
We bring everything the job needs with us. After a quick look at the joints together, we protect the area and start. It normally takes a few hours for a handful of joints, longer for a whole elevation. Somewhere like Dunsbury 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 start by walking round the building and agreeing the joints and the access.
- 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
- Move anything stored near the joints
- Mention any parking rules near the property
- Mention any leaks or damp you’ve noticed
Get a quote
Quotes start with a quick conversation. Describe the problem, the location and the size of the job, and we’ll talk you through what we’d do. Whenever you’re ready, call 0345 464 0079 or email us.
Read more
When to call us in Dunsbury
Buildings move more than people expect. Clay bricks expand slightly over their life, concrete and block shrink, and everything moves with temperature and wet. All of that ends up in the joint sealant.
The problems people usually mention when they call are:
- Sealant that has lost its bond to the brick or render
- Joints with sealant missing in places
- Joints pointed up with cement by mistake
- Cracked joints where brick meets render or frames
For an older house near a landmark such as St. Mary's Church, an extension built onto an older house moves differently, and the joint between them takes the strain.
Comparing quotes
- Whether the sealant suits the joint
- How long the guarantee is
- Which colour the sealant will be
- How long to leave it before use
How to look after the new joints
A little care helps the new joints last. We recommend:
- Point out the joints to other trades
- Avoid pressure-washing directly into sealant joints
- Keep water from gutters off the wall
- Check external joints each spring
If you have more work done on the wall, such as new render, cladding or an opening, show the contractor the movement joints. They must stay as flexible joints, never rendered or pointed over.
Act while the splits are small. Then it’s a straightforward cut-out and reseal with no damage behind it to deal with.