Essex · England
Harwich External Mastic
External mastic in Harwich from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Leaking joints around cladding and façade panels
- Water getting into walls through failed joints
- Old sealant gone brittle and cracked
DIY sealant or a professional job?
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
External mastic for homes and businesses in Harwich
On houses, flats and commercial buildings across Harwich, we reseal joints in brickwork, render, cladding and façade panels. The preparation is the same whatever the wall: clean, sound faces and a controlled depth. We’re often asked to deal with gaps where render, brick and frames meet and plants rooting in failed movement joints, across render & cladding joints, copings & trims and brickwork movement joints.
Plenty of homes in a town like Harwich have been extended, and the line where an extension meets the original house is a common leak point. Sealing it properly means the right joint depth and a flexible sealant, not a quick bead.
The work is guaranteed for twelve months. If there’s a problem with our work within the year, let us know and we will sort it.
- Place
- Harwich (CO12)
- Region
- Essex
- Guarantee
- A year, on every job
- Quote
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Places near Harwich
Other services in Harwich
How the job changes by surface
Cladding and façade panels
Where a cladding system has its own specified sealant, we follow it or an approved alternative. Send us any details you have about the façade.
Render joints
Render has movement joints and stop beads that need sealing. They’re resealed in a sealant that suits the render.
When it isn’t the sealant
A few problems are outside what sealant work can do:
- Cutting new joints into brickwork, which is building work rather than sealant work
- Damp that isn’t coming from the joint
- Cracked brickwork or render that needs a builder or plasterer
If in doubt, call 0345 464 0079 or drop us an email and we will say what we think before you book.
What we seal
- Façade panels
- Joints between brick and frames
- Brickwork movement joints
- Copings & trims
- Render & cladding joints
- Concrete & block
What happens on the day
Once we’re on site, we check the joints match what you told us. If anything is different, we explain it before carrying on. Most jobs then take anything from a few hours to several days, depending on the building. A visit in Harwich needs access to the work and a place to park close by. For outside work, let us know about side access, gates and any upper-floor joints.
- We start by walking round the building and agreeing the joints and the access.
- We cut out the old mastic and rake out anything in the joint.
- Joint faces are cleaned back and primed if the sealant needs it.
- We fit closed-cell backing rod to control the depth.
- We apply the sealant, tool it and check the whole run.
Getting ready for the visit
- Mention any sign-in or site rules at work premises
- Keep pets and children clear of the area while we work
- Let us know if you’ve seen damp or leaks
Getting a quote
For a quote, call 0345 464 0079 or email us and tell us where the job is and what the problem looks like. You will have a clear quote before work begins.
Read more
Outside joints around Harwich
Harwich is close to the coast, and homes near the sea take more wind-driven rain, with salt in the air closer to the shore. Both are hard on movement joints and outside wall joints, which can dry out and crack sooner where a building faces the weather. London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
For an older house near a landmark such as Church of All Saints, older walls, gutters and the joints where extensions meet them need a flexible sealant. For site and facilities teams at buildings such as Harwich and Dovercourt High School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Harwich is in Essex. From the centre of Harwich to the outskirts, external mastic is available for homes and businesses alike, from flats and houses to offices and hotels. Harwich is one of 644 towns and villages in Essex where we work for external mastic. You can also see our page for Chelmsford, about 36 miles away.
Work in CO12 is quoted and booked the same way as anywhere else. Whether your property is on Station Road, High Street and Market Street or anywhere close by, our applicators can take on the job. With the A120 and B1352 close by, Harwich is simple for us to get to. We also cover the places around Harwich: Parkeston (1 mile north-west), Little Oakley (2 miles south-west) and Ramsey (2 miles west). Larger places within reach include Clacton-on-Sea (10 miles south-west), Greenstead (14 miles west), Wivenhoe (14 miles west), Brightlingsea (13 miles south-west), Walton-on-the-Naze (6 miles south) and Bocking's Elm (11 miles south-west).
Landmarks near Harwich
In Harwich, that means homes and buildings near St Joseph's Catholic Primary School and The Trafalgar Public House, among other places. For rail, the closest station is Dovercourt station, about 0.9 miles north-east. Nearby you’ll also find Landguard Fort (2.5 miles east) and Harwich Museum (1.3 miles north-east). Green spaces nearby include Copperas Wood.
Harwich: your questions answered
Can you do external mastic in Harwich?
Yes. Our work covers London and the South East, and Harwich is part of that. You can phone 0345 464 0079 or email us and tell us what needs doing, and we will send you a clear quote.
Is external mastic in a coastal place like Harwich any different?
Coastal homes put outside sealant through more weather than inland ones, so the choice of sealant and the preparation matter even more. Walls facing the sea are normally the first to need attention.
Where do you work from?
Our base is in Crawley, and we cover South East England, London and all of Scotland.
Do you work for landlords and businesses?
Yes. We work for homeowners, landlords, letting agents, businesses and hotels across Essex.
Should I point up the gap in my brickwork?
No. Mortar locks the joint solid, so the movement cracks the wall elsewhere. It needs a flexible sealant over backing rod.
How often do external joints need resealing?
There’s no fixed answer: sunny, exposed elevations and busy joints wear faster. Check them each year and reseal when they split or harden. Our work comes with a one-year guarantee.
Is it OK to seal over old sealant?
No, because it fails. The old sealant always comes out first, so the new sealant bonds properly.
Why is there a gap in my brick wall?
A vertical gap in a long brick wall is normally a movement joint. It lets the bricks expand without cracking.
Landlords, agents and businesses in Harwich
If you manage several properties in or around Harwich, several properties can go on one quote. Just tell us the addresses and what each one needs, and photos by email help.
Hotels need rooms back in use, so the work can be planned room by room. We have worked in hotels as well as homes and businesses.
Signs you need external mastic in Harwich
Buildings move more than people expect. Clay bricks expand slightly over their life, concrete and block shrink, and everything moves with temperature and wet. All of that ends up in the joint sealant.
The most common problems we see are:
- Old sealant gone brittle and cracked
- Rigid filler in a joint that should flex
- Gaps where render, brick and frames meet
- Joints with sealant missing in places
Rented homes near Dovercourt station change hands often, and outside joints that have cracked can let damp into a rental, so check them between lets.
Before booking anyone
- How long the guarantee is
- How the joint is cleaned and prepared
- Whether all the old sealant comes out first
- How hidden problems are handled
Why act early in Harwich
Pointing a movement joint with mortar might seem a neat fix, but it locks the joint solid. The wall then cracks somewhere else. A flexible sealant over backing rod is what the joint needs. Gaps in sealant and mould in the bead never get better on their own, and in a busy home in Harwich they get worse with every use. Replacing the sealant now is the simplest fix.
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether the work is at height. We take all of that into account in your quote.
Why book with us
- A choice of colours where the product allows
- ARBOMaster approved applicator
- Arbo and Everbuild products
- Sanitary silicone with an anti-fungal additive in wet areas
Read our cost guide and what customers say.