Hertfordshire · England
External & façade joints in Langley, Hertfordshire
External mastic across Langley and nearby, with old sealant always removed completely and a 12-month guarantee.
- Cracked joints where brick meets render or frames
- Hard, crazed mastic that has stopped moving
- Sealant pulling away from one side of the joint
Langley buildings and the weather
Historic houses like Knebworth House (about 1.3 miles south-east) are a reminder that the area around Langley has older buildings as well as new. Where a home is older, older brick and stone need a sealant that suits them, at the right joint depth. Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Knebworth House, about 1.3 miles south-east, is one of the historic houses in the wider area around Langley, and older homes nearby need a sealant that suits their walls. For landlords with property near Stevenage station, failed wall and movement joints let damp in, so they’re worth checking between tenancies. For site and facilities teams at buildings such as The Thomas Alleyne School, larger buildings have long runs of movement joint that eventually need resealing.
Langley is about 3 miles south-west of Stevenage, in Hertfordshire. Wherever you are in the SG4 postcode area, our applicators can take on external mastic. 381 places in Hertfordshire are on our list, from the larger towns to small villages. You can also see our page for London, roughly 27 miles from Langley.
Work in SG4 is quoted and booked the same way as anywhere else. That includes homes and businesses on London Road and Village Street. Close by, we work in Langley Bottom (1 mile north-west), Rush Green (1 mile north-west), St Paul's Walden (1 mile west), Old Knebworth (2 miles south-east) and Driver's End (2 miles south). We also work in nearby towns such as Hemel Hempstead (13 miles south-west), Stevenage (3 miles north-east), St Albans (10 miles south-west), Welwyn Garden City (6 miles south), Harpenden (7 miles south-west) and Hitchin (5 miles north).
Around Langley
We work in homes and buildings around Concerts at Knebworth House and Farmers Boy Public House and the streets around them. Langley’s nearest station is Stevenage station, about 1.5 miles north-east. A little further out are Lister Hospital (2.7 miles north) and Wymondley Castle (3.7 miles north). Open spaces near Langley include Ridlins Mire.
External mastic for homes and businesses in Langley
Ground-floor and low-level joints are straightforward to reach. Where joints are higher up, tell us about the building when you get in touch and we will confirm what’s needed to reach them safely. If you have weeds or debris growing in open joints and cracked joints where brick meets render or frames, we can put it right, whatever the surface.
Older homes in small places like Langley may be stone, brick or timber-framed, often with later extensions. The joints where those materials meet are the weak points.
There’s a 12-month guarantee on every job.
- Where
- Langley (SG4)
- Region
- Hertfordshire
- Cover
- One year on every job
- Quote
- A clear quote up front
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Honest limits
We’ll always be straight with you, so here’s what sealant can’t fix:
- Failed render or damaged cladding panels
- Damp that is not coming from the joint
- Cracking across the wall rather than at a joint
Not sure which it is? You can phone 0345 464 0079 or send us an email and we’ll tell you honestly.
Joints and surfaces we work on
- Façade panels
- Joints between brick and frames
- Concrete & block
- Render & cladding joints
- Copings & trims
- Brickwork movement joints
DIY sealant or a professional job?
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and the joint depth matters as much as the finish.
The process
When we arrive, we start by going over the job with you. We protect the surfaces around the joints before any work starts. Most jobs take anything from a few hours to several days, depending on the building. Somewhere like Langley 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.
- First we look over the joints with you, agree which to renew and talk through access.
- We cut out the failed sealant and rake out any dirt or growth.
- Both sides are cleaned back to sound material and primed if needed.
- We push in closed-cell backing rod so the sealant is the right depth and bonds to the sides only.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
How to prepare
- Clear items away from the joints we are working on
- Tell us about access, such as stairs, a lift or high-level joints
- Plan for the work area to be out of bounds to pets and children
Ask for a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and add photos by email if you can.
Read more
What affects the cost of external mastic
We don’t publish a price list. What we look at:
- How many areas need sealing
- The amount of work
- Whether the work is at height
- Whether old sealant or filler has to be cut out
We don’t show prices on the website, because the cost depends so much on the job itself. For a quick quote, please phone 0345 464 0079 or send us an email.
What we need to know
What to tell us when you ask for a quote:
- Any previous sealing or DIY work
- Photos by email, if that is easy
- The type of property
- Where the property is
It all starts with a short chat. Describe the problem, the location and the size of the job. Whenever you are ready, call 0345 464 0079 or send us an email.
Questions from Langley
Is Langley within the area you cover?
Yes, Langley is covered. Our work covers London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
I let a flat near Stevenage station. Can you help?
Yes, landlords and agents are among the people we work for. Just call 0345 464 0079 or drop us an email with the address and what needs doing, and we’ll give you a clear price.
How long will you be here?
Most jobs take a few hours for a handful of joints, longer for a whole elevation. We’ll confirm how long when we quote.
Is there any odour?
Sometimes, a little. Any smell clears as the sealant cures, and ventilation helps.
Can I add another job to the visit?
Yes, we can. Several rooms, windows or areas can go on one quote.
Do you work at height?
It depends on the building. Send us pictures and a rough idea of the height and we’ll confirm how they can be reached safely.
What is a movement joint?
Most straight vertical gaps in brickwork are movement joints. It lets the bricks expand without cracking, and it should be sealed with a flexible sealant.
What sealant do you use?
Products from Arbo and Everbuild, among others, picked for each joint. We’ll tell you what we’re using and why.
What happens if it’s left?
The longer a joint stays open, the more water the wall takes in. In cold weather, frost can damage wet brick and render around the joint, so the problem grows beyond the joint itself. Older cottages and farmhouses around Langley can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
The cost reflects the work involved, not guesswork. That is why we ask about the job first.
What you get with us
- Full insurance on every job
- Quality sealants from Arbo and Everbuild
- We leave the area clean and tidy
- White, clear, grey or coloured to suit, where the product allows
How the job changes by surface
Concrete and blockwork
The face of concrete or block is often dusty, so preparation is key. A primer goes on where the product requires one.
Render joints
Render is weaker at the surface than brick, so a sealant that stretches easily protects the edges. Priming is done where the sealant calls for it.
Places near Langley
More services for Langley
How to look after the new joints
Aftercare is simple:
- Show decorators and builders where the movement joints are
- Avoid pressure-washing directly into sealant joints
- Do not let climbing plants root in the sealant
- Check external joints each spring
Do not let soil, plants or ivy build up against the new joints. Damp material against the sealant shortens its life.
Small splits are the time to act. At that stage it’s a simple cut out and reseal with no damage behind it to deal with.