Hertfordshire · England
Ley Green External Mastic
Movement joints in Ley Green need attention? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Plants rooting in failed movement joints
- Brick movement joints where the sealant has split
- Cracked joints where brick meets render or frames
External mastic for homes and businesses in Ley Green
Many failed façade joints only get noticed once there’s a stain or a damp patch inside. We look over the joints, agree the ones to renew and reseal with a flexible, weatherproof product. Typical jobs include sealant that has lost its bond to the brick or render and rain getting behind render or cladding at a joint, across façade panels, joints between brick and frames and concrete & block.
Outside joints can only be sealed when they’re dry, so work in Ley Green is booked around the forecast. Tell us about access to all sides of the building, including outbuildings and garages.
Whatever the size of the job, it’s backed by our one-year guarantee.
- Place
- Ley Green (SG4)
- Wider area
- Hertfordshire
- Guarantee
- One year on every job
- Quote
- A clear quote up front
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Keeping the joints in good condition
No joint lasts for ever, but care makes a real difference. A few tips:
- Avoid pressure-washing directly into sealant joints
- Ask before painting over external sealant
- Walk round the building once a year and look at the joints
- Point out the joints to other trades
Make sure anyone working on the wall later knows where the movement joints are. They should be kept open and resealed, not filled.
Once a joint can’t move, the wall finds another way, often as cracks near the joint. Catch it early and you reduce the risk.
When it is not the sealant
We will always be straight with you, so here’s what sealant cannot fix:
- Cracking across the wall rather than at a joint
- Movement that’s more than a sealant joint can take
- Damp that is not coming from the joint
Not sure which it is? You can call 0345 464 0079 or send us an email and we will tell you honestly.
Where we work in Ley Green
- Copings & trims
- Façade panels
- Joints between brick and frames
- Concrete & block
- Render & cladding joints
- Brickwork movement joints
Should I try it myself first?
A DIY attempt doesn’t rule out a professional job. We cut it out and start again.
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
The process
There is not much for you to do on the day. Point us to the joints and we’ll get on with it. The job generally takes a few hours for a handful of joints, longer for a whole elevation from start to finish. Somewhere as small as Ley Green, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- First, the joints are inspected and the access agreed.
- Every bit of old sealant and any mortar or debris is cut out.
- Joint faces are cleaned back and primed if the sealant needs it.
- Backing rod sized to the joint goes in to set the depth.
- We apply the sealant, tool it and check the whole run.
Preparing for the visit
- Mention if the joints have been sealed before
- Keep pets and children clear of the area while we work
- For indoor joints, keep the area dry beforehand if you can
How to get a quote
Call for a quick quote, or send an email if you’d rather. Tell us about the joints that need doing and we’ll explain what’s involved before giving you a price.
Related advice
Ley Green: your questions answered
Do you work for landlords with property near Hitchin station?
Yes, rental work is part of what we do. Just call 0345 464 0079 or send us an email and tell us about the property, and we will give you a clear price.
Do you cover smaller places like Ley Green?
Yes. Ley Green is within the area we cover, which takes in towns, villages and rural addresses. Our work covers London and the South East. Just mention lanes, gates or anything else about the route when you book.
How do I get a quote for external mastic in Ley Green?
We don’t publish prices, because the cost depends on the job: how much there is, what’s there now, how we reach it and what it needs. You will get a clear quote before we start.
What should I tell you?
A short description and the location, with pictures by email if possible. We’ll ask anything else we need to know.
What is a movement joint?
A movement joint is a planned break in the wall that absorbs expansion and shrinkage. It’s sealed with a flexible sealant, not mortar.
Where is Mr Mastic based?
Our base is in Crawley, and we work across South East England, London and Scotland.
When is the sealant fully cured?
Many sealants skin over quickly but take longer to cure fully. We will give you the cure time for the product we used.
Do you guarantee your work?
Yes: twelve months. If there’s a problem with our work in that time, tell us and we will put it right.
Common problems we fix in Ley Green
Some movement joints have been pointed up with mortar by mistake. The joint can’t move, so the wall cracks somewhere else instead.
The most common problems we see are:
- Plants rooting in failed movement joints
- Sealant that has lost its bond to the brick or render
- Joints with sealant missing in places
- Movement joints filled with mortar instead of sealant
If you look after a building such as Preston Primary School, its movement joints, gutters and trims need looking after like any other building’s.
What to look for in a quote
- How long the guarantee is
- What happens if the job turns out different
- What preparation is included
- How the colour is chosen
What affects the cost of external mastic
We quote each job individually. These are the things that affect it:
- The product the joint needs
- Whether there’s mould to deal with
- Whether the work is at height
- How much old sealant there is and how hard it is to remove
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. The price is agreed before we begin.
What to tell us for a quote
You don’t need to know the technical terms. It helps if you can tell us:
- Access, such as stairs, a lift or height
- Where the job is, and your postcode
- The type of property
- Pictures of the joints, sent by email
It all starts with a short chat. Describe the problem, the location and the size of the job, and we will explain how we’d tackle it. Whenever you are ready, ring 0345 464 0079 or drop us an email.
What external mastic looks like in Ley Green
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. Historic houses like Knebworth House (about 4.9 miles south-east) are a reminder that the area around Ley Green has older buildings as well as new. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material.
For landlords with property near Hitchin station, failed wall and movement joints let damp in, so they’re worth checking between tenancies. For an older house near a landmark such as Church of St Mary, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Ley Green is about 4 miles south-west of Hitchin, in Hertfordshire. Jobs in Ley Green get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. 381 places in Hertfordshire are on our list, from the larger towns to small villages. For nearby work, see our London page (30 miles or so).
Work in SG4 works the same way as everywhere else we cover. We cover properties on Plough Lane, Whitehall Road and School Lane and the roads around them. We also cover the places around Ley Green: Great Offley (2 miles north-west), Temple End (2 miles north) and The Flints (2 miles north-west). Larger places within reach include Hemel Hempstead (12 miles south-west), Stevenage (6 miles east), St Albans (11 miles south), Welwyn Garden City (9 miles south-east), Harpenden (6 miles south) and Hitchin (4 miles north-east).
Around Ley Green
The closest station to Ley Green is Hitchin station, roughly 4 miles north-east. Well-known places in the area include Wymondley Castle (4.3 miles north-east) and Lister Hospital (4.5 miles east). The countryside around Ley Green includes Markham's Hill and Oughtonhead Nature Reserve.
Why deal with it now?
Done well, a resealed joint is a neat, straight line that suits the wall. A hurried job with smeared edges and no backing looks worse and fails sooner. Where a wall is exposed, as many are in small places like Ley Green, wind-driven rain gets into any failed joint, and damp in older walls is slow to dry out.
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote.
Why Ley Green clients choose us
- Approved under the ARBOMaster scheme
- We are fully insured
- More than 20 years in sealant work
- Colour picked to suit the job
See what affects the cost or our reviews.