West Sussex · England
External & façade joints in River, West Sussex
Specialist external mastic for River: the right sealant, proper preparation and a neat finish. Call for a quick quote.
- Movement joints filled with mortar instead of sealant
- Weeds or debris growing in open joints
- Cracked joints where brick meets render or frames
About our external mastic in River
A movement joint is only as good as its depth. Closed-cell backing rod sets the depth and stops the sealant sticking to the back, so it bonds to the two sides only and can stretch. We are often asked to deal with joints with sealant missing in places and joints where the bead has come unstuck, across copings & trims, façade panels and concrete & block.
Older homes in small places like River may be stone, brick or timber-framed, often with later extensions. The joints where those materials meet are the weak points, and they need the right sealant at the right depth.
A one-year guarantee comes with the work, just as it does everywhere we cover.
- Place
- River (GU28)
- Wider area
- West Sussex
- Guarantee
- 12 months on all our work
- Quote
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
When to call us in River
Many joints fail because they were sealed too deep or with nothing behind them. Sealant bonded to three sides has nowhere to go and tears as soon as the joint widens.
The most common problems we see are:
- Sealant that has lost its bond to the brick or render
- Failed seals between different materials
- Plants rooting in failed movement joints
- Joints with sealant missing in places
In and around River, as anywhere, good external mastic starts with a clean, dry, properly prepared joint.
What to look for in a quote
- Whether they seal over old material or remove it
- What happens if the job turns out different
- How long to leave it before use
- Whether the sealant suits the joint
What we can’t put right
To be straight with you, there are a few things sealant will not fix:
- Cracking across the wall rather than at a joint
- Render that is blown, hollow or coming away
- Rising or penetrating damp from elsewhere in the wall
If you are not sure, just call 0345 464 0079 or send us an email and we’ll give you a straight answer.
What we seal
- Copings & trims
- Joints between brick and frames
- Brickwork movement joints
- Façade panels
- Concrete & block
- Render & cladding joints
Keeping the joints in good condition
Good habits help new joints last longer. Our tips:
- Tell anyone working on the walls about the movement joints
- Look over the joints every year, ideally after winter
- Keep water from gutters off the wall
- Keep high-pressure jets off the joints
Avoid pressure-washing straight into the joints. A strong jet can damage the edges of the bead over time.
Once a joint cannot move, the wall finds another way, often as cracks near the joint. Catch it early and you reduce the risk.
Questions from River
What guarantee comes with external mastic in River?
All our work, in River and everywhere else, comes with a 12-month guarantee. We’re fully insured, and an ARBOMaster approved applicator.
Do you cover smaller places like River?
Yes, we do. We work across London and the South East, and smaller places are part of that. The journey is planned ahead, so it helps to know about access.
Is there any odour?
It depends on the product. Some smell for a while, some hardly at all, and any smell fades as they cure.
Is it messy?
No. The area is protected while we work and cleaned up afterwards.
Can you reach joints on upper floors?
Each building is different. Send us pictures and a rough idea of the height.
What colours does the sealant come in?
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 the joint does not draw the eye.
What should I tell you?
Where the job is, what the problem is and roughly how big it is. Photos by email help too.
Do you have insurance?
Yes. Full insurance covers our work.
Nearby places to River
More services for River
Leave it or put it right?
A low-modulus sealant is chosen because it moves without pulling hard at the 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 River, wind-driven rain gets into any failed joint, and damp in older walls is slow to dry out.
Leaving a failed joint normally makes the job bigger, not smaller, as water and mould keep getting in. If you’re not sure whether it needs doing, phone 0345 464 0079 or email us for an honest opinion and a quote.
Why choose Mr Mastic in River
- Every job guaranteed for a year
- Fully insured
- Domestic, commercial and hotel work
- More than 20 years in sealant work
Read how sealant jobs are priced and our reviews.
DIY versus a professional finish
If you’ve already had a go yourself, that’s fine. We cut it out and start again, so tell us about it when you ask for a quote.
Some sealant jobs are within reach of a careful DIYer, like a short, easy-to-reach joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
What we do, step by step
When we get to you, we compare the joints with what we discussed. If anything is different, we explain it before carrying on. Most jobs then take a few hours to a few days, depending on the length of joint and the access. For a village or hamlet like River, the journey is planned in advance: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- We start by checking each joint, agreeing the ones to redo and how we’ll reach them.
- The old mastic and anything lodged in the joint is removed.
- Both sides are cleaned back to sound material and primed if needed.
- 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.
How to prepare
- Let us know if you’ve seen damp or leaks
- Where the joints are inside, avoid wetting them before we arrive
- Let us know about stairs, lifts or work at height
How to get a quote
For a quick quote, get us on the phone, or send an email if you’d rather. Describe what needs sealing and we will explain what’s involved before giving you a price.
Advice
What affects the cost of external mastic
There’s no set price list, because no two jobs are the same. What we look at:
- How easy the joints are to reach
- The number and length of the joints
- The old material and how stubborn it is
- The type of sealant required
Commercial jobs are quoted on the same basis as homes: the amount of work, how we reach it and what it needs, plus any working-time requirements on site. Call for a quick quote and we’ll go through it with you.
Asking for a quote
When you contact us, these details help:
- Whether it’s a home or a business
- Whether it has been sealed before
- A few pictures by email, if you can
- How many joints, rooms or windows are involved
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and email pictures if that’s easy.
What external mastic looks like in River
Historic houses like Petworth House (about 2.4 miles east) are a reminder that the area around River has older buildings as well as new. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. Rainfall in the South East is lower than in much of the UK, 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 The Parish Church of St Peter, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
River is about 12 miles east of Petersfield, in West Sussex. Whether you’re in the middle of River or further out, external mastic is available for homes and businesses alike, from flats and houses to offices and hotels. Across West Sussex, we cover 371 places, River among them. For nearby work, see our Crawley page.
All of GU28 is covered for external mastic, from the main roads to the quietest streets. We also cover the places around River: Upperton (1 mile east), Selham (2 miles south), Tillington (2 miles south-east), South Ambersham (2 miles south-west) and Hampers Green (2 miles east). Within a short drive, we also cover Bognor Regis (14 miles south), Chichester (12 miles south-west), Littlehampton (14 miles south-east), Rustington (15 miles south-east), Storrington (11 miles south-east) and Billingshurst (9 miles east).
Landmarks near River
Typical jobs here are in homes near The Hollist Arms Public House and the streets around them. Nearby you’ll also find Lodsworth Castle (1.3 miles south) and Coultershaw Heritage Site (3 miles south-east). Not far away are Graffham Common and Blackdown.