Hertfordshire · England
External & façade joints in The Flints, Hertfordshire
External mastic in The Flints from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Plants rooting in failed movement joints
- Old sealant gone brittle and cracked
- Gaps where render, brick and frames meet
The Flints questions
Do you cover The Flints for external mastic?
Yes. We work across London and the South East, and The Flints is part of that. You can phone 0345 464 0079 or email us and tell us what needs doing.
Is The Flints within the area you cover?
Yes. The Flints 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 I need to be at home?
For indoor joints, yes, someone needs to let us in. After that, you can carry on with your day.
When is the sealant fully cured?
Most sealants are touch-dry well before they’re fully cured. We will give you the cure time for the product we used.
What do you need from me for a quote?
Just the basics: the address or postcode, what’s wrong and any access issues. Then ring 0345 464 0079 or drop us an email.
Is there a guarantee?
Yes. All our work carries our one-year guarantee.
How do I get a quote for external mastic in The Flints?
We don’t publish prices, because the cost depends on the job: its size, the old material, access and the product needed. You will get a clear quote before work begins.
Do you do commercial work?
Yes. We have worked for hotels, offices and other businesses, and we are fully insured.
External mastic for homes and businesses in The Flints
Low-level joints can usually be done from the ground. For joints higher up, give us some details of the building and we will confirm what’s needed to reach them safely. We work on render & cladding joints, façade panels and concrete & block, and the jobs we see most are failed seals between different materials and weeds or debris growing in open joints.
External sealant needs dry, clean surfaces, so work around The Flints is planned for dry weather. Tell us about access to all sides of the building, including outbuildings and garages.
We stand behind the work with a 12-month guarantee.
- Location
- The Flints (SG5)
- Wider area
- Hertfordshire
- Guarantee
- One year on every job
- Quote
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Work for landlords, hotels and businesses
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Resealing at the right time is simple maintenance that we can handle for you.
Letting agents often deal with us directly. Tell us the address, the job and how access works and we’ll quote.
Also near The Flints
What else we do in The Flints
The Flints buildings and the weather
The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
For landlords with property near Luton station, outside joints that have cracked can let damp into a rental, so check them between lets. For an older house near a landmark such as Church of St Mary Magdalene, an extension built onto an older house moves differently, and the joint between them takes the strain.
The Flints is about 4 miles south-west of Hitchin, in Hertfordshire. From the centre of The Flints to the outskirts, external mastic is available for homes and businesses alike, from flats and houses to offices and hotels. Our Hertfordshire coverage runs to 381 places, The Flints among them. For nearby work, see our London page (32 miles or so).
Our applicators cover all of SG5 for external mastic. Nearby, we also carry out external mastic in Great Offley (1 mile east), Temple End (2 miles east) and Ley Green (2 miles south-east). We also work in nearby towns such as Hemel Hempstead (13 miles south), Stevenage (7 miles east), St Albans (12 miles south), Welwyn Garden City (11 miles south-east), Harpenden (8 miles south) and Hitchin (4 miles north-east).
Landmarks near The Flints
Locally, jobs take us to homes and businesses close to The Bull Public House and the streets around them. The Flints’s nearest station is Luton station, about 4.1 miles south-west of the centre. Other landmarks nearby include Ravensburgh Castle (2.7 miles north-west) and John Dony Field Centre (2.9 miles south-west). Open spaces near The Flints include Markham's Hill and Pegsdon Hills.
DIY versus a professional finish
A DIY attempt doesn’t rule out a professional job. We cut it out and start again, so tell us about it when you ask for a quote.
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and doesn’t move well, and the joint depth matters as much as the finish.
When to call us in The Flints
Sunlight, wet weather and frost wear exterior sealant down. In time it goes hard, crazes on the surface and stops stretching, so the next time the wall moves, it splits or pulls away.
Keep an eye out for these signs:
- Rain getting behind render or cladding at a joint
- Sealant that has lost its bond to the brick or render
- Old sealant gone brittle and cracked
- Weeds or debris growing in open joints
If you look after a building such as Offley Endowed Primary School, its movement joints, gutters and trims need looking after like any other building’s.
What to look for in a quote
- How the surfaces are prepared before sealing
- How long to leave it before use
- Is VAT in the price?
- Whether they’re fully insured
When something else is needed
We will not take on work that won’t last, so here’s what sealant cannot put right:
- Cracking across the wall rather than at a joint
- Failed render or damaged cladding panels
- Cutting new joints into brickwork, which is building work rather than sealant work
If you are not sure, just ring 0345 464 0079 or email us and we will give you a straight answer.
Surfaces we seal
- Brickwork movement joints
- Copings & trims
- Render & cladding joints
- Façade panels
- Joints between brick and frames
- Concrete & block
Why act early in The Flints
Water gets in through a failed movement joint, behind render and cladding. Resealing early keeps the job to the joint itself, rather than the wall around it. Older cottages and farmhouses around The Flints can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
What it costs depends on the size of the job, how hard the old material is to remove and how easy the joints are to reach. You’ll have a clear quote before any work starts.
Why book with us
- An ARBOMaster approved applicator
- Full insurance on every job
- Arbo and Everbuild products
- White, clear, grey or another colour, product permitting
Take a look at our cost guide and our reviews.
What we do, step by step
We work through the job in order: protection first, then preparation, sealing and a tidy-up. For most jobs that takes anything from a few hours to several days, depending on the building. For a village or hamlet like The Flints, the journey is planned in advance: tell us about narrow lanes, gates, long drives and where we can park. 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.
- Failed sealant is removed back to clean, sound faces.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Preparing for the visit
- For indoor joints, keep the area dry beforehand if you can
- On commercial sites, let us know about site rules
- Mention if the joints have been sealed before
How to get a quote
We don’t publish a price list, because every job is different. Instead, your job gets its own clear quote. To arrange one, ring 0345 464 0079 or send us an email.
Related advice
What affects the cost of external mastic
For a quick quote, just ask. The main things that affect it are:
- The type of sealant required
- How easy the joints are to reach
- How many rooms, windows or areas are involved
- How much old sealant there is and how hard it is to remove
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed, plus any working-time requirements on site. Call for a quick quote and we will explain what it covers.
Helping us quote
Photos by email are helpful but not essential. Please mention:
- Where the job is, and your postcode
- What the problem is, such as mould, gaps, leaks or cracking
- Pictures of the joints, sent by email
- If it’s domestic, commercial or a hotel
Getting a quote is simple: tell us what needs doing and where. A few photos by email make the job easier to understand, and we’ll come back to you with a quote.