Hertfordshire · England
External & façade joints in Hertford, Hertfordshire
Sealing brickwork movement joints, render, cladding and façade joints for homeowners, landlords and businesses in Hertford. Fully insured, ARBOMaster approved and guaranteed for a year.
- Sealant that has lost its bond to the brick or render
- Movement joints filled with mortar instead of sealant
- Weeds or debris growing in open joints
External mastic in Hertford, done properly
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, so it bonds to the two sides only and can stretch. We work on concrete & block, façade panels and brickwork movement joints, and people most often call us about joints pointed up with cement by mistake and movement joints with cracked, split or missing sealant.
Plenty of homes in a town like Hertford have been extended, and the line where an extension meets the original house is a common leak point. Getting the joint depth right matters as much as the sealant itself.
The work is guaranteed for twelve months. If there’s a problem with our work within the year, let us know and we’ll sort it.
- Location
- Hertford (SG14, SG13)
- Region
- Hertfordshire
- Cover
- A year, on every job
- Quotes
- A clear quote up front
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
What affects the cost of external mastic
You’ll get a clear quote before work begins. It’s based on:
- Whether the work is at height
- How many areas need sealing
- When we can work, for business premises
- The old material and how stubborn it is
A few things move the cost up or down: the old material and how easily it comes out, any mould to treat, and whether the work is at height. Your quote takes all of that into account.
What to tell us for a quote
When you contact us, it’s useful to know:
- Where the property is
- Pictures of the joints, sent by email
- Roughly how big the job is
- The type of property
For external mastic in Hertford, phone 0345 464 0079 or drop us an email. Tell us what the problem is and where, and we’ll agree the price before any work begins.
Outside joints around Hertford
London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
If you let a flat or house near Hertford East station, failed wall and movement joints let damp in, so they’re worth checking between tenancies. Homes close to Hertford United Reform Church include some older properties, and older walls, gutters and the joints where extensions meet them need a flexible sealant.
Hertford is about 9 miles south-east of Stevenage, in Hertfordshire. Hertford gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a one-year guarantee. Across Hertfordshire, we cover 381 places, Hertford among them. There’s also a page for London, roughly 21 miles from Hertford.
Postcode districts we cover here for external mastic: SG14 and SG13. That includes homes and businesses on Salisbury Square, Market Street and Parliament Square. Main roads around Hertford include the A10 and A119. Close by, we work in Horns Mill (1 mile south), Foxholes (1 mile east), Rush Green (2 miles east), Hertford Heath (2 miles south-east) and Little Amwell (2 miles south-east). We also work in nearby towns such as Stevenage (9 miles north-west), St Albans (11 miles west), Bishop's Stortford (11 miles north-east), Welwyn Garden City (5 miles west), Harpenden (12 miles west) and Hitchin (13 miles north-west).
Landmarks near Hertford
Locally, jobs take us to homes and businesses close to The Old Barge pub and Richard Hale School, among other places. Hertford has its own railway station: Hertford East station. Well-known places in the area include Hertford County Hospital (under half a mile south-west) and Mcmullen & Sons Brewery Museum (under half a mile south-west). Green spaces nearby include Willowmead.
How to look after the new joints
To keep the joints looking good and working properly:
- Look over the joints every year, ideally after winter
- Keep water from gutters off the wall
- Avoid pressure-washing directly into sealant joints
- Get split or bare joints resealed while the damage is small
Avoid pressure-washing straight into the joints. High-pressure water can lift the edges and let water in behind.
Water getting behind cladding or render can go unnoticed for a long time. When it finally shows inside, the joint may have been open for years, so it’s worth resealing at the first signs.
What happens on the day
We bring everything the job needs with us, so you don’t need to buy or prepare anything. Once we have agreed what’s being done, we protect the area and start. Most jobs take anything from a few hours to several days, depending on the building. For a job in Hertford, we need access to where the work is and somewhere nearby to park. If the job is outside, mention gates, side access and anything above ground floor.
- 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.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
How to prepare
- Move anything stored near the joints
- Mention any tricky access
- For business premises, tell us about site rules or sign-in
Get a quote
We don’t publish a price list. Instead, your job gets its own clear quote. To get started, ring 0345 464 0079 or drop us an email.
Related advice
Landlord and commercial work in Hertford
For anyone letting property in or around Hertford, jobs at different addresses can go on one quote. Send us the addresses and the work at each, and photos by email help.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance.
Towns and villages near Hertford
Also in Hertford
Common problems we fix in Hertford
Every building moves. Clay bricks expand slightly over their life, concrete and block shrink, and everything moves with temperature and wet. All of that ends up in the joint sealant.
Common reasons people contact us are:
- Damp patches traced to an open external joint
- Rigid filler in a joint that should flex
- Brick movement joints where the sealant has split
- Failed seals between different materials
For site and facilities teams at buildings such as Mill Mead Primary School, larger buildings have long runs of movement joint that eventually need resealing.
Before you book anyone
- When the joint can take water or movement
- Whether all the old sealant comes out first
- What product goes in the joint
- What happens if the job turns out different
FAQs for Hertford
Do you work for landlords with property near Hertford East station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. Just phone 0345 464 0079 or send us an email with the address and what needs doing, and we will send you a clear quote.
What guarantee comes with external mastic in Hertford?
Every job comes with our 12-month guarantee, wherever it is. We’re also fully insured and ARBOMaster approved.
Do I have to be there?
For indoor joints, yes, someone needs to let us in. Once we have agreed the job, you do not need to watch us work.
Is there any odour?
There can be a smell while the sealant cures. Ventilation helps.
Can you seal joints between render and window frames?
Yes. The old joint is removed, both surfaces cleaned and primed where needed, and a flexible sealant applied. The colour is chosen to suit.
How do you reach high-level joints?
That depends on how high the joints are and the ground below. Low-level joints are straightforward; for higher ones, send details and we’ll confirm the access.
Will it make a mess?
Very little: the area around the joints is protected first, and we tidy up before we go.
What do you need from me for a quote?
A short description and the location. We’ll ask anything else we need to know.
DIY versus a professional finish
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
Some sealant jobs are within reach of a careful DIYer, 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.
What the job involves on each surface
Copings and trims
A failed coping joint lets water into the top of the wall. Resealing them is a small job that protects a lot.
Brickwork movement joints
Brick movement joints are often mistaken for a missing mortar line. Where one has been mortared, we cut it out and reseal it with sealant.