Hertfordshire · England
External & façade joints in High Wych, Hertfordshire
External mastic for High Wych and the surrounding area: careful preparation, the right product and tidy work. Call for a quick quote.
- Hard, crazed mastic that has stopped moving
- Leaking joints around cladding and façade panels
- Moss and dirt in joints with no sealant left
External mastic for homes and businesses in High Wych
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 where a rigid filler would soon crack. Typical jobs include cracked joints where brick meets render or frames and leaking joints around cladding and façade panels, on concrete & block, render & cladding joints and façade panels.
External sealant needs dry, clean surfaces, so work around High Wych is planned for dry weather. Tell us about access to all sides of the building, including outbuildings and garages.
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
- High Wych (CM21)
- Region
- Hertfordshire
- Guarantee
- A year, on every job
- Quotes
- A clear price before we start
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Looking after it afterwards
Aftercare is simple, and it makes a real difference:
- Deal with leaking gutters that soak the joints below
- Check external joints each spring
- Keep soil, plants and ivy away from the joints
- Check the sealant is paintable before painting near it
Make sure anyone working on the wall later knows where the movement joints are. They must stay as flexible joints, never rendered or pointed over.
A joint that has stopped moving pushes the movement elsewhere, normally as cracking in the brickwork or render nearby. Catch it early and you reduce the risk.
High Wych buildings and the weather
Historic houses like Much Hadham Palace (about 3.9 miles north-west) are a reminder that the area around High Wych has older buildings as well as new. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. The South East is one of 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 let a flat or house near Harlow Mill station, outside joints that have cracked can let damp into a rental, so check them between lets. In the older streets around Parish Church of St James the Great, an extension built onto an older house moves differently, and the joint between them takes the strain.
High Wych is about 3 miles north of Harlow, in Hertfordshire. High Wych gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. High Wych is one of 381 towns and villages in Hertfordshire where we work. Chelmsford is on our list too, about 16 miles from High Wych.
Here we cover the CM21 postcode area for external mastic. Local streets include Mansfield, High Wych Lane and Broadfields. Nearby, we also carry out external mastic in Sawbridgeworth (1 mile east), Lower Sheering (2 miles east), Allen's Green (2 miles north), Spellbrook (2 miles north-east) and Sheering (3 miles east). Larger places within reach include Stevenage (15 miles north-west), Bishop's Stortford (4 miles north), Welwyn Garden City (14 miles west), Hoddesdon (7 miles south-west), Cheshunt (10 miles south-west) and Hatfield (15 miles west).
Local landmarks in High Wych
In High Wych, that means homes and buildings near The Half Moon Public House, Leventhorpe and Gibberd Garden, among other places. The nearest railway station is Harlow Mill station, roughly 1.3 miles south. Nearby you will also find Harlow Mill (1.3 miles south) and Princess Alexandra Hospital (3 miles south-west). For a walk, there’s Sawbridgeworth Marsh.
Your questions about external mastic in High Wych
Can you do external mastic in High Wych?
Yes, High Wych is within the area we cover. Our work covers London and the South East. You can phone 0345 464 0079 or drop us an email and let us know what needs doing, and we’ll give you a clear quote.
Do you cover smaller places like High Wych?
Yes, High Wych is covered. Our work covers London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Do I have to be there?
Access is agreed with you when the job is booked. Indoors, that generally means someone at home.
Can new sealant go over the old?
No, because it fails. We remove every bit of old sealant first, so the new sealant bonds properly.
Will the new joint stand out?
Exterior sealants are made in a range of colours, from greys and browns to whites and stone shades. We choose the closest to your brick or render so the joint does not draw the eye.
Where are you based?
Our base is Crawley, with over 20 years’ experience. We work across South East England, London and Scotland.
Are you an approved applicator?
Yes. We hold ARBOMaster approved applicator status, and we’re fully insured.
Do you work for landlords and businesses?
Yes. As well as householders, we work for landlords, agents, businesses and hotels across Hertfordshire.
What affects the cost of external mastic
The quote reflects the job in front of us. We look at:
- Mould in or behind the old joints
- How many areas need sealing
- The product the joint needs
- Access and height
Combining jobs into one visit usually makes better use of the time than several visits, so tell us about everything that needs sealing. We will give you a clear price for the lot.
What we need to know
To help us quote quickly, let us know:
- The address or postcode of the job
- Whether it has been sealed before
- What’s wrong with the joints now
- A few pictures by email, if you can
For external mastic in High Wych, call 0345 464 0079 or email us. A short description of the job and where it is helps us quote, and you’ll get a clear quote before any work starts.
Do you need external mastic in High Wych?
Poor preparation causes many early failures: joint faces that were dusty or damp, unprimed where they needed it, or still carrying old sealant. The sealant never bonds properly.
Common reasons people contact us include:
- Rigid filler in a joint that should flex
- Leaking joints around cladding and façade panels
- Sealant pulling away from one side of the joint
- Water getting into walls through failed joints
Managing a site like High Wych Church of England Primary School? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
What to look for in a quote
- How the joint is cleaned and prepared
- Who does the work, and how experienced they are
- What the quote includes, VAT included or not
- How hidden problems are handled
Towns and villages near High Wych
Also in High Wych
Work for landlords, hotels and businesses
Hotels need rooms back in use, so we plan the work room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
We also work for property managers and facilities teams in High Wych and across Hertfordshire. Several sites can be quoted together, and we are fully insured for the work.
Why act early in High Wych
Running new sealant over the old bead rarely lasts. The new layer can’t bond properly to old, weathered material, so we always take the old sealant out. Around High Wych, older homes often have timber in their floors and frames, where water from a failed joint can cause rot if it’s left.
Some things make a job bigger or smaller: the old material and how easily it comes out, any mould to treat, and whether we need extra access for height. We take all of that into account in your quote.
What you get with us
- Every job guaranteed for a year
- Rated 4.9 stars on Google
- Approved under the ARBOMaster scheme
- Neat joints and a tidy finish
Take a look at how sealant jobs are priced and what customers say.
How the visit works
On the day, we start by going over the job with you. Surfaces next to the work are protected before any work begins. Most jobs take a few hours for a handful of joints, longer for a whole elevation. Somewhere like High Wych needs a little journey planning: tell us about narrow lanes, gates, long drives and where we can park. Everything for the job comes with us, so a second trip is avoided where possible.
- First, the joints are inspected and the access agreed.
- 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.
Getting ready for the visit
- Clear the area around the work
- Let us know about parking restrictions
- Tell us about any water getting in
Ask for a quote
For a quote, call 0345 464 0079 or send us an email with the location and a short description of the problem. You’ll have a clear quote before work begins.
Read more
DIY sealant or a professional job?
A careful DIYer can reseal a simple joint, such as a straightforward joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.