Hertfordshire · England
External Mastic in Hunsdon
External mastic for Hunsdon, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Old sealant gone brittle and cracked
- Movement joints with cracked, split or missing sealant
- Plants rooting in failed movement joints
External mastic for homes and businesses in Hunsdon
A movement joint is only as good as its depth. Closed-cell backing rod sets the depth and stops the sealant sticking to the back, leaving it bonded to two faces so it can move with the wall. If you have failed seals between different materials and sealant that has lost its bond to the brick or render, we can help.
External sealant needs dry, clean surfaces, so work around Hunsdon is planned for dry weather. Let us know about access to every wall, plus any garages or outbuildings.
We stand behind the work with a one-year guarantee, so you’re not left on your own once the job is done.
- Location
- Hunsdon (SG12)
- Region
- Hertfordshire
- Cover
- One year on every job
- Quotes
- A clear price before we start
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Surface by surface
Cladding and façade panels
Panel systems often rely on sealant between and around the panels. We reseal them with a sealant suited to the panel material.
Joints between dissimilar materials
Each side of the joint may need its own preparation. We prepare both faces so the sealant bonds properly.
For landlords and businesses
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance that we can handle for you.
We also work for property managers and facilities teams. We can quote a run of properties together, and we’re fully insured for the work.
How it works
Every visit runs the same way: we look at the joints together, protect the area around them, 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. For a village or hamlet like Hunsdon, the journey is planned in advance: 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 we look over the joints with you, agree which to renew and talk through access.
- Old sealant and any debris are cut and raked out.
- The joint faces are cleaned and primed where the sealant needs it.
- We push in closed-cell backing rod so the sealant is the right depth and bonds to the sides only.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
Getting ready for the visit
- Let us know about parking restrictions
- Tell us about access, such as stairs, a lift or high-level joints
- Move anything stored near the joints
How to get a quote
To get a quote, call 0345 464 0079 or drop us an email and tell us where the job is and what the problem looks like. You will have a clear quote before we start.
Related advice
Outside joints around Hunsdon
Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. With historic houses such as Much Hadham Palace (about 3.6 miles north) nearby, there’s older building stock in the area around Hunsdon 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.
For site and facilities teams at buildings such as Hunsdon Junior Mixed and Infant School, its movement joints, gutters and trims need looking after like any other building’s. For an older house near a landmark such as St Francis Chapel, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Hunsdon is about 4 miles north-west of Harlow, in Hertfordshire. Whether you are in the middle of Hunsdon or further out, external mastic is available for homes and businesses alike. Across Hertfordshire, we cover 381 places, Hunsdon among them. There’s also a page for Chelmsford, about 19 miles away.
All of SG12 is covered for external mastic. If you need external mastic at a property on High Street, Cunningham Grove and Wicklands Road or a nearby road, we can help. Other places close to Hunsdon include Hunsdonbury (1 mile south), Widford (1 mile north), Nether Street (1 mile north), Wareside (2 miles north-west) and Babbs Green (2 miles north-west). Within a short drive, we also cover Stevenage (12 miles north-west), Bishop's Stortford (6 miles north-east), Welwyn Garden City (11 miles west), Hoddesdon (5 miles south-west), Cheshunt (8 miles south-west) and Hatfield (13 miles west).
Near you in Hunsdon
Around Hunsdon, our work takes us to homes and buildings near The Crown pub. For rail, the closest station is Roydon station, roughly 2.4 miles south of the centre. Well-known places in the area include Harlow Mill (3.3 miles east) and Henry Moore Studios and Gardens (2.4 miles north-east). The countryside around Hunsdon includes Hunsdon Mead.
What affects the quote in Hunsdon
Your quote is based on your job. We look at:
- Mould in or behind the old joints
- How many rooms, windows or areas are involved
- The type of sealant required
- The size of the job
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 we need extra access for height. Your quote takes all of that into account.
Helping us quote
There’s no need for technical detail. Just tell us:
- The rough size of the job
- Whether it’s a home or a business
- What’s wrong with the joints now
- How we’d reach the joints
Call for a quick quote, or email us if that’s easier. Tell us about the joints that need doing and we will explain what’s involved and give you a clear price.
Common problems we fix in Hunsdon
Joints sealed without backing rod, or far too deep, rarely last. If the sealant sticks to the back as well as the sides, it can’t stretch and rips as the joint opens.
Most people get in touch after spotting one of these:
- Moss and dirt in joints with no sealant left
- Joints where the bead has come unstuck
- Failed sealant between panels on a façade
- Hard, crazed mastic that has stopped moving
Letting a property close to Roydon station? Then split movement joints are easy to miss on a rental until damp shows inside.
What your quote should include
- What preparation is included
- Whether all the old sealant comes out first
- Whether you can choose the colour
- Which sealant they’ll use, and why
Also near Hunsdon
What else we do in Hunsdon
Why act early in Hunsdon
The longer a joint stays open, the more water the wall takes in. In cold weather, frost can damage wet brick and render near the open joint, so the problem grows beyond the joint itself. In a small place like Hunsdon, homes can be exposed to wind and rain, which finds any gap, and older walls, once damp, take a long time to dry.
The cost reflects the work involved, not a rough estimate. That is why we ask a few questions first and agree the price before starting.
Why book with us
- We are fully insured
- Sealant colour chosen to suit
- More than 20 years in sealant work
- Rated 4.9 stars on Google
Take a look at what affects the cost or our reviews.
Your questions about external mastic in Hunsdon
Can you do external mastic in Hunsdon?
Yes, Hunsdon 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.
Do you cover smaller places like Hunsdon?
Yes. Hunsdon is within the area we cover, which takes in towns, villages and rural addresses. We work across London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Where is Mr Mastic based?
We’re based in Crawley, West Sussex, and we work across South East England, London and Scotland.
Will you leave a mess?
Very little: the area around the joints is protected first, and we tidy up before we go.
Do the sealants smell?
Possibly a little. Any smell clears as the sealant cures.
Why is there a gap in my brick wall?
It’s a deliberate gap that lets the wall expand and contract without cracking. It’s sealed with a flexible sealant, not mortar.
Can you seal over the old sealant?
No. New silicone won’t bond to old silicone, and it traps any mould or water underneath. It all has to come out first.
How long does external mastic take?
Most jobs take a few hours to a few days, depending on the length of joint and the access, including preparation and clearing up. We will confirm how long when we quote.
DIY sealant or a professional job?
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and doesn’t move well, and getting the depth right matters as much as the look.
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is chosen for how the joint moves and where it is.