West Sussex · England
Flansham External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for Flansham, backed by a one-year guarantee. Call for a quick quote.
- Sealant that has lost its bond to the brick or render
- Rigid filler in a joint that should flex
- Water getting into walls through failed joints
External mastic in Flansham
Getting the depth right is half the job. Backing rod controls how deep the sealant goes and keeps it off the back of the joint, leaving it bonded to two faces so it can move with the wall. We work on render & cladding joints, joints between brick and frames and façade panels, and the jobs we see most are movement joints with cracked, split or missing sealant and joints pointed up with cement by mistake.
Outside joints can only be sealed when they’re dry, so work in Flansham is booked around the forecast. Tell us about access to all sides of the building, including outbuildings and garages.
You’re covered for a year from the day we finish. If anything is not right with it, phone 0345 464 0079 or drop us an email.
- Place
- Flansham (PO22)
- Wider area
- West Sussex
- Cover
- A year, on every job
- Quotes
- A clear quote up front
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Work for landlords, hotels and businesses
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we will quote.
Housing providers, facilities teams and property managers book us too in Flansham and across West Sussex. We can quote a run of properties together.
Towns and villages near Flansham
Other services in Flansham
FAQs for Flansham
Does the coastal weather in Flansham affect outside sealant?
Near the sea, outside joints face more wind, rain and salt than they would inland, so the choice of sealant and the preparation matter even more. Walls facing the sea are generally the first to need attention.
Can you help a landlord with a rental near Barnham station?
Yes, we work for landlords and letting agents. Just ring 0345 464 0079 or send us an email and tell us about the property, and we will give you a clear quote.
Can you seal over the old sealant?
No. Fresh sealant does not stick to old sealant, and anything trapped underneath, including mould and water, stays there. We remove it all first.
Do the sealants smell?
Possibly a little. It fades as the sealant cures.
How long does external mastic last?
It depends on the exposure, the movement and the product. Treat it as a maintenance item and look at it yearly and reseal when it splits.
Why is there a gap in my brick wall?
A movement joint is a planned break in the wall that absorbs expansion and shrinkage. It’s sealed with a flexible sealant, not mortar.
Which products do you use?
It depends on the joint: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. We use products from Arbo and Everbuild.
Where is Mr Mastic based?
We are a Crawley-based firm, with over 20 years’ experience. Our area covers South East England, London and Scotland.
How the visit works
We work through the job in order: protection first, then preparation, sealing and a tidy-up. For most jobs that takes a few hours to a few days, depending on the length of joint and the access, and the area is left clean. Somewhere like Flansham 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 inspect the joints and agree which need resealing and how they’ll be reached.
- The old mastic and anything lodged in the joint is removed.
- We clean both faces of the joint and prime them where the product calls for it.
- Backing rod goes in next, setting the depth and keeping the sealant off the back of the joint.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
Before we arrive
- Plan for the work area to be out of bounds to pets and children
- For indoor joints, keep the area dry beforehand if you can
- Tell us about any previous sealing or DIY attempts
Ask for a quote
We do not publish a price list, because every job is different. Instead, we send you a clear quote for your job. To get started, phone 0345 464 0079 or email us.
Advice
Honest limits
We won’t take on work that will not last, so here’s what sealant cannot put right:
- Damp that isn’t coming from the joint
- Loose or hollow render, which needs re-rendering
- Cracking across the wall rather than at a joint
Not sure which it is? You can ring 0345 464 0079 or send us an email and we’ll tell you honestly.
Where we work in Flansham
- Copings & trims
- Joints between brick and frames
- Brickwork movement joints
- Façade panels
- Render & cladding joints
- Concrete & block
DIY sealant or a professional job?
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.
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Aftercare tips
After the cure time, these simple habits help:
- Wash walls gently around the sealant
- Ask before painting over external sealant
- Show decorators and builders where the movement joints are
- Do not let climbing plants root in the sealant
Don’t let soil, plants or ivy build up against the new joints. Anything that holds water against the joint wears it out sooner.
Leave a failed movement joint and water keeps getting into the wall. That can lead to damp patches, staining and frost damage.
What external mastic looks like in Flansham
Flansham is within about 2 miles 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. Rainfall in the South East is lower than in much of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Rented homes near Barnham station change hands often, and split movement joints are easy to miss on a rental until damp shows inside. For site and facilities teams at buildings such as Bishop Tufnell CofE Primary School, larger buildings have long runs of movement joint that eventually need resealing.
Flansham is about 2 miles north-east of Bognor Regis, in West Sussex. For external mastic in and around Flansham, it’s easy to get a quote: please ring 0345 464 0079 or email us. We are based in Crawley and cover West Sussex. Across West Sussex, we cover 371 places, Flansham among them. You can also see our page for Portsmouth, roughly 19 miles from Flansham.
We cover every part of the PO22 postcode area for external mastic. We also cover Bilsham (1 mile east), Lidsey (2 miles north-west), Shripney (2 miles west), Yapton (2 miles north-east) and Barnham (2 miles north). We also work in nearby towns such as Worthing (11 miles east), Chichester (7 miles west), Selsey (8 miles south-west), Littlehampton (5 miles east), Lancing (14 miles east) and Emsworth (13 miles west).
Near you in Flansham
In Flansham, that means homes and buildings near Felpham Community College and The Brooks Local Nature Reserve. For rail, the closest station is Barnham station, roughly 1.9 miles north of the centre. A little further out are Tote Copse Castle (3.1 miles north-west) and Bognor Regis Museum (2.3 miles south-west).
Common problems we fix in Flansham
Poor preparation causes many early failures: joint faces that were dusty or damp, unprimed where they needed it, or still carrying old sealant. The new sealant then lets go long before it should.
If you can see any of these, it’s time to have the joints looked at:
- Joints with sealant missing in places
- Failed seals between different materials
- Joints pointed up with cement by mistake
- Weeds or debris growing in open joints
Homes close to Bilsham Chapel include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain.
Before booking anyone
- Whether all the old sealant comes out first
- Is VAT in the price?
- How hidden problems are handled
- Who does the work, and how experienced they are
Why deal with it now?
Low-modulus sealants stretch easily, so they put less strain on the joint edges. That protects surfaces like brick, render and concrete. A stiffer product can damage the joint edge as it fails. Where a wall is exposed, as many are in small places like Flansham, wind-driven rain gets into any failed joint, 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. Call for a quick quote and we’ll talk you through it.
Why Flansham clients choose us
- Domestic, commercial and hotel work
- A choice of colours where the product allows
- Anti-fungal silicone where joints get wet
- An ARBOMaster approved applicator
Take a look at how sealant jobs are priced and what customers say.