Isle of Wight · England
External Mastic in Blackgang
External mastic in Blackgang from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Gaps where render, brick and frames meet
- Sealant pulling away from one side of the joint
- Rigid filler in a joint that should flex
External mastic in Blackgang, done properly
We cut out failed sealant, set the joint depth with closed-cell backing rod and reseal with a low-modulus exterior sealant. The colour is chosen to suit the brick or render so the line blends in. If you’re dealing with failed sealant between panels on a façade and sealant that has lost its bond to the brick or render, we can put it right, whatever the surface.
Outside joints can only be sealed when they’re dry, so work in Blackgang is booked around the forecast. Let us know about access to every wall, plus any garages or outbuildings.
All our work comes with our one-year guarantee.
- Location
- Blackgang (PO38)
- Region
- Isle of Wight
- Cover
- 12 months on all our work
- Quote
- Quoted before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Can I do it myself?
A DIY attempt does not rule out a professional job. We cut it out and start again.
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.
Leave it or put it right?
Running new sealant over the old bead rarely lasts. New sealant doesn’t bond well to old, weathered sealant, so we always take the old sealant out. In a small place like Blackgang, homes can be exposed to wind and rain, which finds any gap, and damp in older walls is slow to dry out.
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, along with when we can work on site. Ask us for a quote and we’ll go through it with you.
Why Blackgang clients choose us
- ARBOMaster approved applicator
- You choose the colour before work begins
- Homes, businesses and hotels
- Sealant colour chosen to suit
Take a look at what affects the cost and our reviews.
Your questions about external mastic in Blackgang
Do you cover smaller places like Blackgang?
Yes, Blackgang is covered. We work across London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Is Blackgang in your area for external mastic?
Yes. Our work covers London and the South East, and Blackgang is part of that. You can call 0345 464 0079 or drop us an email and tell us what needs doing.
Are you an approved applicator?
Yes. We are an ARBOMaster approved applicator.
Can you reach joints on upper floors?
It depends on the height and the site. Ground-floor joints are simple; for higher ones, send details and we’ll confirm the access.
Do you work for landlords and businesses?
Yes. We work for homeowners, landlords, letting agents, businesses and hotels across the Isle of Wight.
Can you do several jobs on one visit?
Yes. Tell us about everything you’d like done.
What is backing rod for?
Closed-cell backing rod sets the depth of the sealant and stops it sticking to the back of the joint. That way it bonds to the two sides only and can stretch.
Can I do it myself?
Some simple jobs can be done by a careful DIYer. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
What external mastic looks like in Blackgang
Blackgang is within about 1 mile of the coast, and homes near the sea take more wind-driven rain, with salt in the air closer to the shore. Both are hard on movement joints and outside wall joints, which can dry out and crack sooner where a building faces the weather. Historic houses like Wolverton Manor (about 4.1 miles north-west) are a reminder that the area around Blackgang has older buildings as well as new. Where a home is older, older brick and stone need a sealant that suits them, at the right joint depth.
In the older streets around St Andrew's Church, older walls, gutters and the joints where extensions meet them need a flexible sealant.
Blackgang is about 6 miles south-west of Shanklin, in the Isle of Wight. Anywhere in PO38, we can carry out external mastic at your property. Our the Isle of Wight coverage runs to 125 places, Blackgang among them. You can also see our page for Portsmouth, roughly 18 miles from Blackgang.
All of PO38 is covered for external mastic, from the main roads to the quietest streets. Nearby, we also carry out external mastic in Chale (1 mile north-west), Niton (1 mile east), Puckaster (1 mile south-east), Pyle (1 mile north-west) and Bierley (1 mile north-east). Larger places within reach include Newport (8 miles north), Ryde (11 miles north-east), Cowes (12 miles north), Sandown (8 miles north-east), Shanklin (6 miles north-east) and Ventnor (4 miles east). For island and remote addresses, the job takes a little more planning, so let us know when you get in touch.
Local landmarks in Blackgang
A little further out are Blackgang Sawmill Museum (less than half a mile west) and Whitecroft Hospital (5.7 miles north). The countryside around Blackgang includes Stenbury Down.
Common problems we fix in Blackgang
If plants are growing out of a joint, the sealant has usually failed or was never there. Roots and dirt hold water against the wall and speed up the damage.
Common reasons people contact us include:
- Plants rooting in failed movement joints
- Gaps where render, brick and frames meet
- Panel joints letting water in
- Damp patches traced to an open external joint
For site and facilities teams at buildings such as Niton Primary School, larger buildings have long runs of movement joint that eventually need resealing.
What your quote should include
- What insurance they hold
- Whether the sealant suits the joint
- The length of the guarantee
- What the quote includes, VAT included or not
Looking after it afterwards
A little care helps the new joints last. Our advice:
- Clear growth from the base of walls and joints
- Never let anyone fill a movement joint with mortar
- Check the sealant is paintable before painting near it
- Act on the first splits you see
Make sure anyone working on the wall later knows where the movement joints are. They should be kept open and resealed, not filled.
A joint that has stopped moving pushes the movement elsewhere, often as cracks near the joint. Resealing it early helps prevent that.
Also in Blackgang
Honest limits
In fairness, there are a few things sealant won’t fix:
- Cracked brickwork or render that needs a builder or plasterer
- Movement that is more than a sealant joint can take
- Cutting new joints into brickwork, which is building work rather than sealant work
If in doubt, call 0345 464 0079 or send us an email and we will say what we think.
Where we work in Blackgang
- Façade panels
- Joints between brick and frames
- Concrete & block
- Render & cladding joints
- Copings & trims
- Brickwork movement joints
The process
There is not much for you to do on the day. Point us to the joints and we will get on with it. The job generally takes anything from a few hours to several days, depending on the building from start to finish. In a small place like Blackgang, access is generally the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- We look at every joint and agree a colour to suit the wall.
- We take out the old sealant until the faces are sound.
- Backing rod goes in so the sealant can stretch between the two faces.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Getting ready for the visit
- For business premises, tell us about site rules or sign-in
- Tell us if parking is tricky
- Mention any tricky access
Get a quote
For external mastic in Blackgang, phone 0345 464 0079 or drop us an email. Tell us what the problem is and where, and we will agree the price before any work begins.
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What the job involves on each surface
Concrete and blockwork
Blockwork and concrete shrink over time and move with the seasons. We reseal their joints with backing rod and a flexible product.
Brickwork movement joints
Brick movement joints are often mistaken for a missing mortar line. Where one has been mortared, we cut it out and reseal it with sealant if the joint can be cleared.