West Sussex · England
Barns Green External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for householders, landlords and businesses in Barns Green. Fully insured, ARBOMaster approved and guaranteed for a year.
- Movement joints with cracked, split or missing sealant
- Panel joints letting water in
- Failed seals between different materials
How we handle external mastic in Barns Green
Joints between dissimilar materials, like brick against render or concrete against a steel frame, see movement from both sides. A flexible sealant bridges the two. We work on render & cladding joints, copings & trims and façade panels, and people most often call us about plants rooting in failed movement joints and joints where the bead has come unstuck.
Somewhere as small as Barns Green, homes and farm buildings often face open ground, so walls and rooflines take the full force of wind and rain. Gutter joints and wall joints there need a sealant that can flex and stay put.
Every job comes with a one-year guarantee, wherever you are in West Sussex.
- Where
- Barns Green (RH13)
- Region
- West Sussex
- Cover
- A year, on every job
- Price
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Work for landlords, hotels and businesses
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements and we’ll quote.
Hotels need rooms back in use, so we plan the work room by room around your bookings where we can. We have worked in hotels as well as homes and businesses.
Signs you need external mastic in Barns Green
Many joints fail because they were sealed too deep or with nothing behind them. If the sealant sticks to the back as well as the sides, it can’t stretch and rips as the joint opens.
The problems people generally mention when they call include:
- Weeds or debris growing in open joints
- Brick movement joints where the sealant has split
- Cracked joints where brick meets render or frames
- Rigid filler in a joint that should flex
For site and facilities teams at buildings such as Barns Green Primary School, larger buildings have long runs of movement joint that eventually need resealing.
Comparing quotes
- Whether all the old sealant comes out first
- The length of the guarantee
- What preparation is included
- How the colour is chosen
Can I do it myself?
If you do try it yourself, take your time over the preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.
What we do, step by step
A visit follows a simple pattern: we check the joints, mask and protect the surrounding surfaces, do the work and tidy away. It usually takes a few hours to a few days, depending on the length of joint and the access. Somewhere as small as Barns Green, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- 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.
- The faces are brushed clean and primed where the product requires it.
- We fit closed-cell backing rod to control the depth.
- The exterior sealant is applied, tooled and checked along its length.
How to prepare
- Mention any tricky access
- Move anything stored near the joints
- Keep children and pets away from the work area
Ask for a quote
We don’t publish a price list. Instead, your job gets its own clear quote. To arrange one, ring 0345 464 0079 or send us an email.
Related advice
What external mastic looks like in Barns Green
London and the South East are among the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Letting a property close to Christs Hospital station? Then split movement joints are easy to miss on a rental until damp shows inside.
Barns Green is about 4 miles south-west of Horsham, in West Sussex. We carry out external mastic for homes and businesses in Barns Green and nearby, as part of our work across West Sussex. Barns Green is one of 371 towns and villages in West Sussex where we work for external mastic. You can also see our page for Crawley, roughly 10 miles from Barns Green.
Our applicators cover all of RH13 for external mastic and the streets around it. If you need external mastic at a property on The Hordens, Smugglers Way and Finians Field or anywhere close by, we can help. We also cover the places around Barns Green: Brooks Green (1 mile south), Itchingfield (1 mile north), Southwater (2 miles east), Tower Hill (3 miles north-east) and Broadbridge Heath (3 miles north-east). We also work in nearby towns such as Crawley (10 miles north-east), Worthing (14 miles south), Haywards Heath (13 miles east), Burgess Hill (13 miles south-east), Shoreham-by-Sea (14 miles south) and Lancing (14 miles south).
Landmarks near Barns Green
Locally, jobs take us to homes and businesses close to The Queen's Head Public House, among other places. Barns Green’s nearest station is Christs Hospital station, about 1.9 miles north-east. Well-known places in the area include Horsham Hospital (4 miles north-east) and Christs Hospital School Museum (1.6 miles north-east). Open spaces near Barns Green include Knepp Wildland.
When something else is needed
Before booking, it’s worth knowing the limits:
- Damp that is not coming from the joint
- Cutting new joints into brickwork, which is building work rather than sealant work
- Loose or hollow render, which needs re-rendering
Not sure which it is? You can phone 0345 464 0079 or drop us an email and we will tell you honestly.
What we seal
- Render & cladding joints
- Concrete & block
- Copings & trims
- Joints between brick and frames
- Façade panels
- Brickwork movement joints
Keeping the joints in good condition
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Walk round the building once a year and look at the joints
- Never let anyone fill a movement joint with mortar
- Get split or bare joints resealed while the damage is small
- Avoid pressure-washing directly into sealant joints
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.
If you can see gaps, plants or bare sections in a joint, have it checked. Earlier resealing means a smaller job and a better result.
Surface by surface
Copings and trims
Coping joints that leak let water straight down into the wall. Resealing them is a small job that protects a lot.
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.
Places near Barns Green
Also in Barns Green
Questions from Barns Green
Do you cover Barns Green for external mastic?
Yes. We work across London and the South East, and Barns Green is part of that. Just ring 0345 464 0079 or drop us an email with a few details of the job, and we will give you a clear price.
Can you help a landlord with a rental near Christs Hospital station?
Yes, rental work is part of what we do. Just ring 0345 464 0079 or send us an email and tell us about the property, and we will send you a clear quote.
Can new sealant go over the old?
No, because it fails. The old sealant always comes out first, so the new sealant bonds properly.
Can a movement joint be filled with mortar?
No, not where the gap is a movement joint. Filling it with mortar defeats its purpose, and the wall may crack nearby. A flexible sealant is the right fill.
Does someone need to be in?
Access is agreed with you when the job is booked. Indoors, that usually means someone at home.
Do you work for hotels and businesses?
Yes. Hotels, offices and other businesses use us.
How long should I leave it?
That depends on the sealant used, so please follow the time we give you.
How do you reach high-level joints?
Each building is different. Send us photos and a rough idea of the height.