West Sussex · England
Rock External Mastic
Sealing brickwork movement joints, render, cladding and façade joints in Rock, with a one-year guarantee on every job. Ask us for a quote.
- Weeds or debris growing in open joints
- Leaking joints around cladding and façade panels
- Movement joints filled with mortar instead of sealant
Common questions in Rock
Do you cover smaller places like Rock?
Yes. Rock is within the area we cover, which takes in towns, villages and rural addresses. We work across London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Can you do external mastic in Rock?
Yes. We work across London and the South East, and Rock is part of that. You can call 0345 464 0079 or email us and let us know what needs doing, and we will give you a clear quote.
Is it OK to fill a movement joint with cement?
No. A mortar-filled joint cannot move, so the wall cracks somewhere else instead. Use a flexible sealant with backing rod.
What is a movement joint?
A vertical gap in a long brick wall is usually a movement joint. It lets the bricks expand without cracking.
Are you an approved applicator?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we’re part of it.
What do you need from me for a quote?
A short description and the location, plus pictures if you have them. We will ask anything else we need to know.
Will there be a smell?
It depends on the product. Some smell for a while, some hardly at all.
Is it OK to seal over old sealant?
No, and we never do. It can look neat for a few weeks, but the new layer lifts away from the old one. Removing the old sealant completely is the only lasting way.
How we handle external mastic in Rock
Ground-floor and low-level joints are straightforward to reach. For joints higher up, give us some details of the building and we’ll confirm what’s needed to reach them safely. We’re often asked to deal with movement joints with cracked, split or missing sealant and damp patches traced to an open external joint, across façade panels, brickwork movement joints and joints between brick and frames.
Outside joints can only be sealed when they’re dry, so work in Rock is booked around the forecast. Tell us about access to all sides of the building, including outbuildings and garages.
Big or small, it’s backed by our 12-month guarantee in Rock and across West Sussex.
- Where
- Rock (RH20)
- Wider area
- West Sussex
- Cover
- One year on every job
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Nearby places to Rock
What else we do in Rock
What happens if it’s left?
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. Where a wall is exposed, as many are in small places like Rock, wind-driven rain gets into any failed joint, and damp in older walls is slow to dry out.
The cost depends on the amount of work, how much old material has to come out and how easy the joints are to reach. We give a clear quote before work begins.
What you get with us
- Old sealant always removed completely
- Arbo and Everbuild products
- An ARBOMaster approved applicator
- Sanitary silicone with an anti-fungal additive in wet areas
Read how sealant jobs are priced and our reviews.
Rock buildings and the weather
With historic houses such as Parham House (about 3.9 miles west) nearby, there’s older building stock in the area around Rock as well as newer homes. Where a home is older, older brick and stone need a sealant that suits them, at the right joint depth. The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Homes close to The Parish Church of St Mary include some older properties, and the joints between older walls, newer extensions and the roofline need a sealant that can move. Managing a site like St Mary's CofE Primary School? Then larger buildings have long runs of movement joint that eventually need resealing.
Rock is about 6 miles north of Worthing, in West Sussex. If you need external mastic in Rock, please ring 0345 464 0079 or drop us an email for a quick quote. We’re based in Crawley and cover West Sussex. 371 places in West Sussex are on our list, large and small. There’s also a page for Brighton, roughly 13 miles from Rock.
Here we cover the RH20 postcode area for external mastic. Streets in the area include Old London Road, London Road and Lamorna Close, and we cover them all. Nearby, we also carry out external mastic in Washington (1 mile south), Heath Common (1 mile north-west), Sullington (1 mile west), Warminghurst (2 miles north) and Storrington (2 miles west). Larger places within reach include Horsham (11 miles north), Worthing (6 miles south), Bognor Regis (15 miles south-west), Haywards Heath (15 miles north-east), Burgess Hill (12 miles east) and Littlehampton (9 miles south-west).
Around Rock
Around Rock, our work takes us to homes and buildings near Rydon Community College and The Frankland Arms Public House and the streets around them. Well-known places in the area include The Storrington And District Museum (1.9 miles west). For a walk, there’s Chanctonbury Hill.
For landlords and businesses
Failed sealant is one of the commonest items on a check-out report. We can quote for more than one property at once.
For anyone letting property in or around Rock, several properties can go on one quote. Just tell us the addresses and what each one needs.
What affects the cost of external mastic
Call for a quick quote. The main things that affect it are:
- The old material and how stubborn it is
- Working hours on commercial sites
- How many rooms, windows or areas are involved
- Mould in or behind the old joints
What you pay reflects the work, not a rough estimate. That is why we ask a few questions first.
What to tell us for a quote
The more you tell us, the more accurate the quote. When you ask for a quote, tell us:
- Pictures of the joints, sent by email
- The address or postcode of the job
- What the problem is, such as mould, gaps, leaks or cracking
- Whether it’s a home or a business
Getting a quote is simple: let us know the job and the location and its rough size. Photos by email help us understand the job, and we will take it from there.
Keeping the joints in good condition
A little care helps the new joints last. We recommend:
- Clear growth from the base of walls and joints
- Look over the joints every year, ideally after winter
- Get split or bare joints resealed while the damage is small
- Keep water from gutters off the wall
Do not let soil, plants or ivy build up against the new joints. Damp material against the sealant shortens its life.
Small splits are the time to act. Then it’s a straightforward cut-out and reseal before water has had years to get in.
What we can’t put right
In fairness, some problems need a different trade:
- Walls that need new movement joints cut into them
- Subsidence or other structural problems
- Cracked brickwork or render that needs a builder or plasterer
If you are not sure, just phone 0345 464 0079 or drop us an email and we will give you a straight answer.
Surfaces we seal
- Concrete & block
- Copings & trims
- Render & cladding joints
- Joints between brick and frames
- Façade panels
- Brickwork movement joints
How it works
Once we are on site, 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. Somewhere like Rock 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.
- First, the joints are inspected and the access agreed.
- 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.
- Backing rod sized to the joint goes in to set the depth.
- The exterior sealant is applied, tooled and checked along its length.
Before we arrive
- For indoor joints, keep the area dry beforehand if you can
- Mention any parking rules near the property
- Tell us about any water getting in
Getting a quote
We do not publish a price list. Instead, your job gets its own clear quote. To arrange one, ring 0345 464 0079 or drop us an email.
Advice
Different surfaces, different methods
Render joints
Water behind render can lead to blown patches. A sound joint keeps the render dry behind and protects the render itself.
Copings and trims
Copings expand and contract through the day, so a flexible sealant suits them best year round.