East Sussex · England
External Mastic in Gun Hill
External mastic for Gun Hill and the surrounding area: careful preparation, the right product and tidy work. Call for a quick quote.
- Movement joints filled with mortar instead of sealant
- Panel joints letting water in
- Brick movement joints where the sealant has split
How to look after the new joints
How long the joints last depends on use and care. Here’s what we suggest:
- Make sure movement joints are not pointed over
- Wash walls gently around the sealant
- Have failed joints looked at early
- Deal with leaking gutters that soak the joints below
Avoid pressure-washing straight into the joints. High-pressure water can lift the edges over time.
An open movement joint lets rain into the wall every time it pours. Over time it can mean damp inside, stained render or frost-damaged brick, all bigger jobs than a reseal.
How we handle external mastic in Gun Hill
We are ARBOMaster approved applicators, and each external joint gets a sealant suited to it. Some surfaces need a primer before sealing. We are often asked to deal with rain getting behind render or cladding at a joint and gaps where render, brick and frames meet, across façade panels, render & cladding joints and concrete & block.
Outside joints can only be sealed when they’re dry, so work in Gun Hill is booked around the forecast. Let us know about access to every wall, plus any garages or outbuildings.
We guarantee the work for a year. If there’s a problem with our work within the year, let us know and we’ll sort it.
- Where
- Gun Hill (TN21)
- Wider area
- East Sussex
- Cover
- A year, on every job
- Quotes
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Surface by surface
Joints between dissimilar materials
Wherever two materials meet, they move differently. A flexible sealant bridges the two.
Copings and trims
Coping joints that leak let water straight down into the wall. Resealing them is a small job that protects a lot.
Also near Gun Hill
Also in Gun Hill
Why act early in Gun Hill
The longer a joint stays open, the more water the wall takes in. In cold weather, frost can damage wet brick and render around the joint, so the damage spreads beyond the joint. Around Gun Hill, older homes often have timber in their floors and frames, and water through a failed joint can rot timber if it’s left.
Rather than a set price list, we look at what your job involves: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
Why book with us
- Rated 4.9 stars on Google
- We agree the colour with you first
- Full insurance on every job
- Neat joints and a tidy finish
See how sealant jobs are priced and our reviews.
Walls and rooflines in Gun Hill
With historic houses such as Horselunges Manor (about 1.9 miles south-east) nearby, there’s older building stock in the area around Gun Hill 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. 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.
In and around Gun Hill, as anywhere, good external mastic starts with a clean, dry, properly prepared joint. Historic houses such as Horselunges Manor, about 1.9 miles south-east, show how far back building around Gun Hill goes.
Gun Hill is about 3 miles north-west of Hailsham, in East Sussex. Gun Hill gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a one-year guarantee. Gun Hill is one of 289 places in East Sussex we cover for external mastic. You can also see our page for Brighton, roughly 16 miles from Gun Hill.
Jobs for external mastic in TN21 works the same way as everywhere else we cover. Other places close to Gun Hill include Hale Green (1 mile west), Muddles Green (1 mile south-west), Burlow (1 mile north-east), Horam (2 miles north-east) and Lions Green (2 miles north). Further out, we also cover Eastbourne (9 miles south), Hastings (15 miles east), Bexhill-on-Sea (11 miles east), Seaford (10 miles south-west), Lewes (10 miles west) and Hailsham (3 miles south-east).
What’s near Gun Hill
Nearby you’ll also find Hellingly Hospital Railway (2.1 miles south-east) and Sussex Farm Museum (1.9 miles north-east). Green spaces nearby include Selwyns Wood.
Questions from Gun Hill
Can you do external mastic in Gun Hill?
Yes. We work across London and the South East, and Gun Hill is part of that. Just phone 0345 464 0079 or drop us an email with a few details of the job, and we will give you a clear price.
What guarantee comes with external mastic in Gun Hill?
All our work, in Gun Hill and everywhere else, comes with a 12-month guarantee. We are fully insured, and an ARBOMaster approved applicator.
Do you remove the old sealant?
Yes. We cut out all the old sealant and clean the joint before resealing.
How long does the job take?
Typically it takes anything from a few hours to several days, depending on the building. Larger jobs naturally take longer, and we’ll tell you how long to expect.
Which products do you use?
We choose the sealant for the joint, not the other way round. Movement, water and weather all affect the choice.
Are you ARBOMaster approved?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we are part of it.
What is a movement joint?
It’s a deliberate gap that lets the wall expand and contract without cracking. It should be filled with flexible sealant, never mortar.
Will there be a smell?
That depends on the sealant. Some smell for a while, some hardly at all, and any smell fades as they cure.
What affects the cost of external mastic
The quote reflects the job in front of us. We look at:
- Which sealant suits the joint
- Any working-time requirements on site
- How much there is to do
- Mould in or behind the old joints
Combining jobs into one visit is normally more efficient than separate visits. You’ll get one clear quote for the whole job.
What we need to know
You don’t need to know the technical terms. It helps if you can tell us:
- What the problem is, such as mould, gaps, leaks or cracking
- Where the job is, and your postcode
- Roughly how big the job is
- Whether it has been sealed before
Need a quote? Please phone 0345 464 0079 or send us an email and tell us about the job. We will explain what we’d do and give you a clear quote before we start.
Landlords, agents and businesses in Gun Hill
We also work for businesses, from offices to washrooms and kitchens. For commercial premises, we can talk through working times when we quote.
Mouldy or split sealant often shows up at the end of a tenancy. We can quote for more than one property at once.
How the visit works
Before we leave, we go over the finished joints with you and tell you how long to leave it. The visit itself generally takes a few hours for a handful of joints, longer for a whole elevation, depending on the amount of work. In a small place like Gun Hill, access is usually the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- First we look over the joints with you, agree which to renew and talk through access.
- The old mastic and anything lodged in the joint is removed.
- Both sides are cleaned back to sound material and primed if needed.
- Closed-cell backing rod is fitted to set the depth and stop three-sided bonding.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
How to prepare
- Where the joints are inside, avoid wetting them before we arrive
- Let us know about parking restrictions
- Mention any sign-in or site rules at work premises
Get a quote
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is. Whenever you are ready, phone 0345 464 0079 or drop us an email.
Related advice
Honest limits
Honest advice matters more to us than a booking, so here’s what sealant cannot fix:
- Adding movement joints to masonry that has none
- Failed render or damaged cladding panels
- Damp that is not coming from the joint
Not sure which it is? You can ring 0345 464 0079 or send us an email and we’ll tell you honestly before booking.
Surfaces we seal
- Copings & trims
- Brickwork movement joints
- Render & cladding joints
- Joints between brick and frames
- Concrete & block
- Façade panels