Hertfordshire · England
External Mastic in Jockey End
Sealing brickwork movement joints, render, cladding and façade joints for Jockey End, backed by a 12-month guarantee. Call for a quick quote.
- Brick movement joints where the sealant has split
- Leaking joints around cladding and façade panels
- Water getting into walls through failed joints
How we handle external mastic in Jockey End
Short cuts in external joints show up within a season or two. New sealant over old, joints packed with mortar and beads with no backing rarely last long. We strip the joint back and start again. We work on copings & trims, render & cladding joints and concrete & block, and the jobs we see most are sealant pulling away from one side of the joint and old sealant gone brittle and cracked.
Older homes in small places like Jockey End may be stone, brick or timber-framed, often with later extensions. The joints where those materials meet are the weak points, and they need the right sealant at the right depth.
Big or small, it’s backed by our 12-month guarantee.
- Where
- Jockey End (HP2)
- Region
- Hertfordshire
- Guarantee
- 12 months on all our work
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
DIY versus a professional finish
If you are set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
Some sealant jobs are within reach of a careful DIYer, like a short, easy-to-reach joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
When it isn’t the sealant
We’ll always be straight with you, so here’s what sealant can’t fix:
- Cutting new joints into brickwork, which is building work rather than sealant work
- Cracked brickwork or render that needs a builder or plasterer
- Render that’s blown, hollow or coming away
If in doubt, call 0345 464 0079 or email us and we will say what we think before you book.
Where we work in Jockey End
- Render & cladding joints
- Brickwork movement joints
- Joints between brick and frames
- Façade panels
- Concrete & block
- Copings & trims
What the job involves on each surface
Joints between dissimilar materials
Different materials may need different primers. We prepare both faces so the sealant bonds properly.
Cladding and façade panels
Metal and composite panels move a lot with temperature, so the joints work hard every day. We choose the product to suit.
What affects the cost of external mastic
You’ll get a clear quote before we start. It’s based on:
- Working hours on commercial sites
- Whether the work is at height
- How much old sealant there is and how hard it is to remove
- The number and length of the joints
The cost reflects the work involved, not guesswork. That is why we ask a few questions first.
What to tell us for a quote
Before you ask for a quote, have a think about:
- Photos by email, if that is easy
- Access, such as stairs, a lift or height
- Whether it has been sealed before
- The address or postcode of the job
We quote each job on its own, so start by telling us what you need. Simply phone 0345 464 0079 or email us and describe the job and send pictures if you have them.
When to call us in Jockey End
Some movement joints have been pointed up with mortar. With the joint locked solid, the movement turns into cracks elsewhere in the wall.
Most people get in touch when they notice one of these:
- Water getting into walls through failed joints
- Rigid filler in a joint that should flex
- Sealant that has lost its bond to the brick or render
- Hard, crazed mastic that has stopped moving
For landlords with property near Berkhamsted station, outside joints that have cracked can let damp into a rental, so check them between lets.
Comparing quotes
- What the cure time is
- What happens if the job turns out different
- Who does the work, and how experienced they are
- Whether they seal over old material or remove it
Jockey End buildings and the weather
The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Schools such as Gaddesden Row JMI School are buildings too, and movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Jockey End is about 4 miles north of Hemel Hempstead, in Hertfordshire. We carry out external mastic for householders, landlords and businesses in Jockey End and nearby, as part of our work across Hertfordshire. Jockey End is one of 381 towns and villages in Hertfordshire where we work for external mastic. London is on our list too, about 28 miles from Jockey End.
Postcode districts we cover here for external mastic: HP2. External mastic is available to properties on West Dene, Johnson Court and Gaddesden Row and the roads around them. We also cover the places around Jockey End: Ballingdon Bottom (1 mile north-west), Roe End (1 mile north-east), Markyate (2 miles north-east), Trowley Bottom (2 miles east) and Flamstead (2 miles east). We also work in nearby towns such as Watford (11 miles south), Hemel Hempstead (4 miles south), Stevenage (15 miles north-east), St Albans (8 miles south-east), Welwyn Garden City (13 miles east) and Harpenden (6 miles east).
Local landmarks in Jockey End
The closest station to Jockey End is Berkhamsted station, about 4.6 miles south-west of the centre. A little further out are Hemel Hempstead Hospital (4.4 miles south). Open spaces near Jockey End include Landpark Wood.
Common questions in Jockey End
Do you work for landlords with property near Berkhamsted station?
Yes, we work for landlords and agents. Just call 0345 464 0079 or email us and tell us about the property, and we will give you a clear price.
Will you come out to Jockey End?
Yes. Jockey End 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.
Do you work for hotels and businesses?
Yes. Commercial and hotel work is a large part of what we do, as well as homes. We can talk about working times when we quote.
Is it OK to seal over old sealant?
No, it will not last. It may look fine at first, but the new layer lifts away from the old one. Removing the old sealant completely is the only lasting way.
Will the new joint stand out?
We choose a sealant colour to suit the brick, stone or render so the joint blends in. Exterior sealants come in a good range of colours.
Why is there a gap in my brick wall?
A movement joint is a planned break in the wall that absorbs expansion and shrinkage. It should be filled with flexible sealant, never mortar.
Which products do you use?
We choose the sealant for the joint, not the other way round. Where it moves, gets wet or faces the weather makes a difference.
Is it worth trying it myself?
Some simple jobs can be done by a careful DIYer. Most DIY failures come from sealing over old material, wet joints or too much sealant.
What happens on the day
Most of a good job is in the preparation, and we do not rush it. Joints are cleaned back and dried before anything new goes in. All told, the work takes a few hours for a handful of joints, longer for a whole elevation. Somewhere like Jockey End 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 look at every joint and agree a colour to suit the wall.
- We take out the old sealant until the faces are sound.
- Backing rod goes in so the sealant can stretch between the two faces.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
Getting ready for the visit
- Clear the area around the work
- Mention if the joints have been sealed before
- For business premises, tell us about site rules or sign-in
Get a quote
A good description makes for an accurate quote. Tell us where the job is, what’s wrong and how much there is.
Read more
Why deal with it now?
A low-modulus sealant is chosen because it moves without pulling hard at the edges. That protects surfaces like brick, render and concrete. Too stiff a sealant can pull at the edges and break them. Around Jockey End, 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 price the job in front of us: how many joints, what’s in them now and how we reach them. You will know the price before we begin.
What you get with us
- Sanitary silicone with an anti-fungal additive in wet areas
- Trusted Arbo and Everbuild sealants
- Over 20 years’ experience
- Full insurance on every job
Take a look at what affects the cost or our reviews.