Hertfordshire · England
External Mastic in Thundridge
Professional external mastic in and around Thundridge, with every bit of old sealant taken out first and a one-year guarantee.
- Leaking joints around cladding and façade panels
- Moss and dirt in joints with no sealant left
- Hard, crazed mastic that has stopped moving
How we handle external mastic in Thundridge
External mastic is a job where short cuts show quickly. Overfilled joints, missing backing rod and sealant laid over old sealant all tend to fail early. We strip the joint back and start again. We are often asked to deal with gaps where render, brick and frames meet and old sealant gone brittle and cracked, on copings & trims, façade panels and render & cladding joints.
Somewhere as small as Thundridge, homes and farm buildings often face open ground, so walls and rooflines take the full force of wind and rain. Gutter joints and wall joints there need a sealant that can flex and stay put.
We guarantee the work for a year. If there’s a problem with our work within the year, let us know and we will sort it.
- Place
- Thundridge (SG12)
- Region
- Hertfordshire
- Cover
- A year, on every job
- Quotes
- A clear quote up front
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
What affects the cost of external mastic
We quote each job individually. These are the things that affect it:
- Any working-time requirements on site
- How much old sealant there is and how hard it is to remove
- Which sealant suits the joint
- Whether there’s mould to deal with
We don’t show prices on the website, because each job is priced on what it involves. For a quick quote, please call 0345 464 0079 or drop us an email and we’ll talk you through it.
What to tell us for a quote
The more you tell us, the more accurate the quote. When you get in contact, it helps to mention:
- Pictures of the joints, sent by email
- The address or postcode of the job
- Roughly how big the job is
- Whether it has been sealed before
We quote each job on its own. Just phone 0345 464 0079 or email us with the details and send pictures if you have them.
Walls and rooflines in Thundridge
With historic houses such as Much Hadham Palace (about 4.8 miles east) nearby, there’s older building stock in the area around Thundridge as well as newer homes. 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.
For site and facilities teams at buildings such as Thundridge Church of England Primary School, larger buildings have long runs of movement joint that eventually need resealing. If you live in an older home near Parish Church of St Mary, the joints between older walls, newer extensions and the roofline need a sealant that can move.
Thundridge is about 1 mile north of Ware, in Hertfordshire. If you need external mastic in Thundridge, please phone 0345 464 0079 or email us for a quick quote. We are based in Crawley and cover Hertfordshire. 381 places in Hertfordshire are on our list. There’s also a page for London, about 23 miles away.
Every address in SG12 is covered for external mastic, from the main roads to the quietest streets. That includes homes and businesses on Woodlands Road, Cold Christmas Lane and Ducketts Wood and the roads around them. If you are just outside Thundridge, we cover Wadesmill (1 mile north), Cold Christmas (1 mile east), High Cross (1 mile north), Ware (1 mile south) and Tonwell (2 miles west). Larger places within reach include Stevenage (8 miles north-west), St Albans (14 miles south-west), Bishop's Stortford (8 miles east), Welwyn Garden City (7 miles west), Harpenden (14 miles west) and Hitchin (13 miles north-west).
Around Thundridge
Around Thundridge, our work takes us to homes and buildings near Sow & Pigs pub and The Chauncy School and the streets around them. For rail, the closest station is Ware station, about 1.8 miles south. Other landmarks nearby include Hertford County Hospital (3.6 miles south-west) and Barrowfield (2.5 miles south). Green spaces nearby include King's Meads.
Also near Thundridge
Other services in Thundridge
Keeping the joints in good condition
Looking after new joints is easy, and it makes a real difference:
- Check the sealant is paintable before painting near it
- Point out the joints to other trades
- Make sure movement joints are not pointed over
- Clear growth from the base of walls and joints
Have a quick look at the joints each spring. Watch for splits, edges coming away or growth in the joint.
Water getting behind cladding or render can go unnoticed for a long time. By the time there’s a damp patch, the damage can be well established, so it’s worth resealing at the first signs.
What happens on the day
Before we leave, we go over the finished joints with you and explain the cure time. The visit itself generally takes anything from a few hours to several days, depending on the building, depending on the size of the job. For a village or hamlet like Thundridge, 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.
- 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.
Preparing for the visit
- Clear the area around the work
- Mention any sign-in or site rules at work premises
- Mention if the joints have been sealed before
Ask for a quote
It all starts with a short chat. Describe the problem, the location and the size of the job, and we’ll explain how we’d tackle it. When it suits you, call 0345 464 0079 or drop us an email.
Related advice
Thundridge: your questions answered
Will you come out to Thundridge?
Yes, Thundridge is covered. Our work covers London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
Do you cover Thundridge for external mastic?
Yes. Our work covers London and the South East, and Thundridge is part of that. Just call 0345 464 0079 or drop us an email with a few details of the job.
Do you have insurance?
Yes. Mr Mastic is fully insured.
Can you work on commercial sites?
Yes. We’ve worked for hotels, offices and other businesses, and we’re fully insured.
Can you quote for more than one area?
Yes. Several rooms, windows or areas can go on one quote.
Do you seal joints where cladding meets other materials?
Yes. Different materials move at different rates, so a flexible sealant is needed where they meet. The sealant is matched to both sides.
Do you take out the old sealant first?
Always. Sealing over old sealant is the main reason resealing fails early, so we never do it.
I’m a tenant. Can you help?
We are happy to deal with the tenant, landlord or agent. Just make sure your landlord agrees.
Do you need external mastic in Thundridge?
Poor preparation causes many early failures: dusty or wet faces, no primer where one was needed, or old sealant left in. The sealant never bonds properly.
Keep an eye out for these signs:
- Moss and dirt in joints with no sealant left
- Hard, crazed mastic that has stopped moving
- Gaps where render, brick and frames meet
- Joints where the bead has come unstuck
For landlords with property near Ware station, split movement joints are easy to miss on a rental until damp shows inside.
What your quote should include
- What the quote includes, VAT included or not
- What product goes in the joint
- What happens if they find a problem under the old sealant
- What insurance they hold
Can I do it myself?
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.
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
For landlords and businesses
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements.
In hotels, rooms out of use cost money, so we plan the work room by room. Hotel work is part of what we do, alongside homes and businesses.
Why it’s worth doing now in Thundridge
Sealing over the top of old mastic does not hold for long. The new layer cannot bond properly to old, weathered material, so the old joint is cut out fully first. Older cottages and farmhouses around Thundridge can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
The cost depends on the size of the job, how much old material has to come out and access to the work. We give a clear quote before any work starts, so you know where you stand.
Why book with us
- Every job guaranteed for a year
- A choice of colours where the product allows
- We agree the colour with you first
- Any old sealant cut out fully, not covered over