Hertfordshire · England
External & façade joints in Newgate Street, Hertfordshire
External mastic for Newgate Street and the surrounding area: careful preparation, the right product and tidy work. Call for a quick quote.
- Sealant pulling away from one side of the joint
- Movement joints with cracked, split or missing sealant
- Panel joints letting water in
What we cannot put right
In fairness, some problems need a different trade:
- Subsidence or other structural problems
- Rising or penetrating damp from elsewhere in the wall
- Render that’s blown, hollow or coming away
If you’re not sure, just ring 0345 464 0079 or send us an email and we’ll give you a straight answer.
Where we work in Newgate Street
- Copings & trims
- Render & cladding joints
- Joints between brick and frames
- Brickwork movement joints
- Concrete & block
- Façade panels
About our external mastic in Newgate Street
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’ll confirm what access is needed. If you are dealing with panel joints letting water in and cracked joints where brick meets render or frames, we can put it right, whatever the surface.
Outside joints can only be sealed when they’re dry, so work in Newgate Street is booked around the forecast. Let us know about access to every wall, plus any garages or outbuildings.
Each job carries a 12-month guarantee, large or small.
- Place
- Newgate Street (SG13)
- Region
- Hertfordshire
- Cover
- 12 months on all our work
- Price
- A clear price before work begins
- Call
- 0345 464 0079
- Updated
- 26 October 2026
DIY sealant or a professional job?
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Sealing over old silicone is the commonest DIY error. New silicone won’t bond to old, so it peels away and traps moisture behind it. Everything old must be removed first.
What we do, step by step
You don’t need to clear the whole room or building, just the space around the work. We protect the rest, and the job takes anything from a few hours to several days, depending on the building for a typical job. For a village or hamlet like Newgate Street, the journey is planned in advance: tell us about narrow lanes, gates, long drives and where we can park. We bring what the job needs, so it can be finished in one trip where possible.
- We start by checking each joint, agreeing the ones to redo and how we’ll reach them.
- The old mastic and anything lodged in the joint is removed.
- The joint faces are cleaned and primed where the sealant needs it.
- Backing rod goes in next, setting the depth and keeping the sealant off the back of the joint.
- The new sealant, chosen to suit the brick or render, is applied and tooled to a neat finish.
Preparing for the visit
- On commercial sites, let us know about site rules
- Mention any tricky access
- Keep pets and children clear of the area while we work
Ask for a quote
Quotes start with a quick conversation. Describe the problem, the location and the size of the job. Whenever you are ready, ring 0345 464 0079 or email us.
Advice
What affects the cost of external mastic
We quote each job individually. This is what makes a difference:
- The amount of work
- The type of sealant required
- Whether the work is at height
- When we can work, for business premises
Leaving a failed joint generally makes the job bigger, not smaller, because water and mould keep working on it. If you are unsure, phone 0345 464 0079 or send us an email for an honest opinion and a quote.
Helping us quote
To make quoting easier, let us know:
- How we’d reach the joints
- Whether it has been sealed before
- If it’s domestic, commercial or a hotel
- Where the job is, and your postcode
Every job is quoted individually, so the first step is telling us about yours. Simply ring 0345 464 0079 or drop us an email and describe the job, and photos are welcome.
Leave it or put it right?
Pointing a movement joint with mortar might seem a neat fix, but it locks the joint solid. The movement then cracks the brickwork or render nearby. The correct repair is a flexible sealant with the right backing. Where a wall is exposed, as many are in small places like Newgate Street, wind-driven rain gets into any failed joint, and damp in older walls is slow to dry out.
Some things make a job bigger or smaller: the old material and how easily it comes out, any mould to treat, and whether the work is at height. We take all of that into account in your quote.
Why choose Mr Mastic in Newgate Street
- Over 20 years’ experience
- Any old sealant cut out fully, not covered over
- Neat joints and a tidy finish
- 180+ five-star Google reviews
See what affects the cost and what customers say.
External mastic in Newgate Street: local notes
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. Historic houses like Wyllyotts Manor (about 4 miles south-west) are a reminder that the area around Newgate Street 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.
If you let a flat or house near Cuffley station, outside joints that have cracked can let damp into a rental, so check them between lets. If you look after a building such as Ponsbourne St Mary's Church of England Primary School, its movement joints, gutters and trims need looking after like any other building’s. If you live in an older home near Church of St Mary Ponsbourne, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Newgate Street is about 3 miles north-west of Cheshunt, in Hertfordshire. Whether you are in the middle of Newgate Street or further out, external mastic is available for homes and businesses alike, from flats and houses to offices and hotels. 381 places in Hertfordshire are on our list. There’s also a page for London, roughly 16 miles from Newgate Street.
Work in SG13 works the same way as everywhere else we cover. Whether your property is on Newgate Street Village, Carbone Hill and The Ridings or a nearby road, we can help. We also cover the places around Newgate Street: Cuffley (1 mile south), Little Berkhamsted (2 miles north), Northaw (2 miles south-west), Bayford (2 miles north) and Essendon (3 miles north-west). Larger places within reach include Watford (13 miles west), Hemel Hempstead (15 miles west), Stevenage (13 miles north), St Albans (9 miles west), Bishop's Stortford (15 miles north-east) and Welwyn Garden City (6 miles north-west).
What’s near Newgate Street
Locally, jobs take us to homes and businesses close to The Coach And Horses Public House and the streets around them. The closest station to Newgate Street is Cuffley station, about 1.4 miles south of the centre. A little further out are Chase Farm Hospital (4.3 miles south) and Hertford Castle (4.9 miles north). Green spaces nearby include Fir and Pond Woods and Cheshunt Lake.
Work for landlords, hotels and businesses
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we will quote.
Towns and villages near Newgate Street
More services for Newgate Street
Keeping the joints in good condition
So the new joints stay in good condition:
- Never let anyone fill a movement joint with mortar
- Wash walls gently around the sealant
- Leave the joints unpainted unless we’ve said otherwise
- Fix overflowing gutters above sealed joints
Follow the cure time we give you before the joint is knocked or disturbed. Most exterior sealants skin fast but take longer to cure right through.
Gaps, plants or missing sealant in a joint are worth getting looked at. Early work is quicker and leaves a better finish.
Questions from Newgate Street
Is Newgate Street in your area for external mastic?
Yes. Our work covers London and the South East, and Newgate Street is part of that. Just phone 0345 464 0079 or email us with a few details of the job.
I let a flat near Cuffley station. Can you help?
Yes, we work for letting agents and landlords. You can phone 0345 464 0079 or email us with the address and a few details, and we will give you a fixed price before we start.
How long does the job take?
It depends on the size of the job, but most jobs take a few hours to a few days, depending on the length of joint and the access. We’ll tell you when we quote.
Where do you work from?
We’re based in Crawley, and we work across South East England, London and Scotland.
Will the old sealant be removed?
Yes, every time. New silicone doesn’t stick to old silicone, so any old material comes out before anything new goes in.
Should I try DIY first?
It depends on the job. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional, while a short indoor joint may be within reach.
Can you seal joints between render and window frames?
Yes. Joints between dissimilar materials are a big part of external work. We use a flexible sealant suited to both surfaces with primer where required.
Does someone need to be in?
That depends on where the joints are. Inside work needs someone to give us access.