West Sussex · England
External Mastic in Chelwood Gate
External mastic for Chelwood Gate, by sealant specialists with 20+ years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Weathered mastic that no longer stretches
- Gaps where render, brick and frames meet
- Brick movement joints where the sealant has split
Can I do it myself?
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and the joint depth matters as much as the finish.
Sealing over old silicone is the commonest DIY error. New silicone won’t bond to old, so it lifts and traps water and mould underneath. Everything old must be removed first.
External mastic for homes and businesses in Chelwood Gate
Joints between dissimilar materials, like brick against render or concrete against a steel frame, see movement from both sides. A flexible exterior sealant takes up that movement. If you have hard, crazed mastic that has stopped moving and damp patches traced to an open external joint, we can help, whatever the surface.
External sealant needs dry, clean surfaces, so work around Chelwood Gate is planned for dry weather. Let us know about access to every wall, plus any garages or outbuildings.
Our work is backed for twelve months, in Chelwood Gate and everywhere else we cover.
- Where
- Chelwood Gate (RH17)
- Region
- West Sussex
- Cover
- One year on every job
- Quote
- A clear price before we start
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
How to look after the new joints
Looking after new joints is easy:
- Keep soil, plants and ivy away from the joints
- Tell anyone working on the walls about the movement joints
- Check the sealant is paintable before painting near it
- Look over the joints every year, ideally after winter
Give the sealant the cure time we tell you before anything rubs against it. The surface skins over quickly, but full cure takes longer.
Small splits are the time to act. Then it’s a straightforward cut-out and reseal before water has had years to get in.
How it works
There is not much for you to do on the day. Show us the job and we’ll take it from there. The job generally takes a few hours to a few days, depending on the length of joint and the access, including the tidy-up. Somewhere like Chelwood Gate needs a little journey planning: 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 will reach them.
- 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.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
How to prepare
- Clear the area around the work
- Tell us about any previous sealing or DIY attempts
- Mention any leaks or damp you’ve noticed
Ask for a quote
To get a quote, phone 0345 464 0079 or email us with the location and a short description of the problem. We’ll give you a clear quote before any work starts.
Advice
Nearby places to Chelwood Gate
More services for Chelwood Gate
Why it’s worth doing now in Chelwood Gate
Resealing a run of joints in one go is generally better than patching one at a time. Joints of the same age tend to fail together, and access only has to be arranged once. Around Chelwood Gate, older homes often have timber in their floors and frames, where water from a failed joint can cause rot if it’s left.
The cost reflects the work involved, not a rough estimate. That’s why we ask about the job first and agree the price before starting.
Why choose Mr Mastic in Chelwood Gate
- Over 20 years’ experience
- Colour agreed with you before work begins
- Approved under the ARBOMaster scheme
- Quality sealants from Arbo and Everbuild
Chelwood Gate questions
Is external mastic in Chelwood Gate guaranteed?
All our work, in Chelwood Gate and everywhere else, comes with a 12-month guarantee. We are fully insured, and an ARBOMaster approved applicator.
Is Chelwood Gate in your area for external mastic?
Yes, Chelwood Gate is within the area we cover. Our work covers London and the South East. Just phone 0345 464 0079 or send us an email with a few details of the job.
Do you work for letting agents?
Yes, regularly. We can quote for several properties at once, and between tenancies is a good time for the work.
Are you ARBOMaster approved?
Yes. We’re approved under the ARBOMaster scheme.
Where is Mr Mastic based?
We are a Crawley-based firm, with over 20 years’ experience. We work across South East England, London and Scotland.
Can you seal joints between render and window frames?
Yes. We cut out the old sealant, prepare both faces and reseal with a flexible exterior product. We pick a colour that works with both materials.
Can you match the colour of my brickwork?
The sealant colour is picked to suit the wall so the joint blends in. Exterior sealants come in a good range of colours.
Do I need to be at home?
We need access to the joints, so we’ll agree that with you when we book. For inside work, that normally means someone being in.
How we quote for external mastic
For a quick quote, just ask. The main things that affect it are:
- The number and length of the joints
- How easy the joints are to reach
- The old material and how stubborn it is
- Working hours on commercial sites
Doing several joints on one visit normally makes better use of the time than several visits. We will give you a clear quote for the lot.
What to tell us for a quote
Photos by email are helpful but not essential. Try to tell us:
- If it’s domestic, commercial or a hotel
- Roughly how big the job is
- If someone has resealed it before
- Access, such as stairs, a lift or height
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we will explain how we’d tackle it. When it suits you, call 0345 464 0079 or drop us an email.
Do you need external mastic in Chelwood Gate?
If plants are growing out of a joint, the sealant has normally failed or was never there. Roots and dirt hold water against the wall and speed up the damage.
Common reasons people contact us include:
- Rain getting behind render or cladding at a joint
- Sealant that has lost its bond to the brick or render
- Old sealant gone brittle and cracked
- Failed sealant between panels on a façade
In and around Chelwood Gate, as anywhere, good external mastic starts with a clean, dry, properly prepared joint.
What to look for in a quote
- How the joint is cleaned and prepared
- Whether VAT is included
- How much experience the applicator has
- How long the guarantee is
External mastic in Chelwood Gate: local notes
With historic houses such as Priest House (about 3.8 miles north-west) nearby, there’s older building stock in the area around Chelwood Gate 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. London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
If you live in an older home near Chelwood Gate Church, the joints between older walls, newer extensions and the roofline need a sealant that can move.
Chelwood Gate is about 6 miles south of East Grinstead, in West Sussex. Wherever you are in the RH17 postcode area, our applicators can take on external mastic. Across West Sussex, we cover 371 places, Chelwood Gate among them. There’s also a page for Crawley, about 10 miles away.
Work in RH17 is quoted and booked the same way as anywhere else. That includes homes and businesses on Beaconsfield Road, Stone Quarry Road and Isle of Thorns and the roads around them. Neighbouring places we cover for external mastic include Chelwood Common (1 mile south), Birchgrove (1 mile west), Wych Cross (1 mile north), Danehill (2 miles south-west) and Nutley (2 miles south-east). Further out, we also cover Crawley (10 miles north-west), Horsham (15 miles west), Haywards Heath (6 miles south-west), Burgess Hill (9 miles south-west), East Grinstead (6 miles north) and Broadfield (10 miles west).
Near you in Chelwood Gate
A little further out are Waterbury Castle (2.6 miles west) and Crowborough War Memorial Hospital (5.9 miles east). Not far away are Brickfield Meadow.
Surface by surface
Concrete and blockwork
Wide joints in concrete need the depth controlling carefully. Backing rod sized to the joint sets it and keep the sealant to the right depth.
Brickwork movement joints
Brick movement joints are often mistaken for a missing mortar line. If that’s happened, we rake it out and reseal it properly.