Hertfordshire · England
External Mastic in Tonwell
Our applicators work in Tonwell on sealing brickwork movement joints, render, cladding and façade joints. Old sealant removed completely, joints prepared properly and every job guaranteed for a year.
- Hard, crazed mastic that has stopped moving
- Damp patches traced to an open external joint
- Plants rooting in failed movement joints
Leave it or put it right?
The longer a joint stays open, the more water the wall takes in. Wet masonry is more easily damaged by frost near the open joint, so the problem grows beyond the joint itself. In a small place like Tonwell, homes can be exposed to wind and rain, which finds any gap, and older walls, once damp, take a long time to dry.
The cost reflects the work involved, not a rough estimate. That’s why we ask about the job first and agree the price before starting.
Why Tonwell customers choose us
- Sealant colour chosen to suit
- White, clear, grey or another colour, product permitting
- We agree the colour with you first
- Approved under the ARBOMaster scheme
See what affects the cost or our reviews.
External mastic in Tonwell
We cut out failed sealant, set the joint depth with closed-cell backing rod and reseal with a low-modulus exterior sealant. The colour is chosen to suit the brick or render so the joint does not stand out. We work on joints between brick and frames, copings & trims and brickwork movement joints, and common reasons people get in touch are rain getting behind render or cladding at a joint and weathered mastic that no longer stretches.
External sealant needs dry, clean surfaces, so work around Tonwell is planned for dry weather. Tell us about access to all sides of the building, including outbuildings and garages.
Every job comes with a one-year guarantee.
- Where
- Tonwell (SG12)
- Wider area
- Hertfordshire
- Cover
- One year on every job
- Quote
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
What happens on the day
When we arrive, we look over the joints with you first, so you know exactly what we’re doing. Surfaces next to the work are protected before any work starts. The work generally takes a few hours for a handful of joints, longer for a whole elevation. In a small place like Tonwell, access is normally the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- We inspect the joints and agree which need resealing and how they’ll be reached.
- Old sealant and any debris are cut and raked out.
- Both sides are cleaned back to sound material and primed if needed.
- 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.
Getting ready for the visit
- Let us know about earlier repairs to the joints
- Keep children and pets away from the work area
- Clear items away from the joints we’re working on
Ask for a quote
For a quote, phone 0345 464 0079 or send us an email with the location and a short description of the problem. You will have a clear quote before work begins.
Advice
When to call us in Tonwell
Weeds, moss and debris in a joint are a sign the sealant has gone. Roots and dirt hold water against the wall.
Signs it’s time to call us include:
- Leaking joints around cladding and façade panels
- Plants rooting in failed movement joints
- Joints where the bead has come unstuck
- Failed seals between different materials
Aston Bury, about 4.6 miles north-west, is one of the historic houses in the wider area around Tonwell.
Questions to ask before you book
- What happens if they find a problem under the old sealant
- How much experience the applicator has
- Is the old sealant removed completely?
- Which colour the sealant will be
Also near Tonwell
Other services in Tonwell
What sealant work can’t fix
Honest advice matters more to us than a booking, so here’s what sealant can’t fix:
- Damp that isn’t coming from the joint
- Cutting new joints into brickwork, which is building work rather than sealant work
- Loose or hollow render, which needs re-rendering
Not sure which it is? You can call 0345 464 0079 or drop us an email and we will tell you honestly before booking.
What we seal
- Brickwork movement joints
- Copings & trims
- Concrete & block
- Façade panels
- Joints between brick and frames
- Render & cladding joints
Your questions about external mastic in Tonwell
Will you come out to Tonwell?
Yes. Tonwell is within the area we cover, which takes in towns, villages and rural addresses. Our work covers London and the South East. Just mention lanes, gates or anything else about the route when you book.
Is Tonwell in your area for external mastic?
Yes. Our work covers London and the South East, and Tonwell is part of that. You can ring 0345 464 0079 or send us an email and let us know what needs doing.
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.
Can I add another job to the visit?
Yes, we can. More than one area can be quoted together.
Do you have insurance?
Yes. Full insurance covers our work.
Do you work at height?
It depends on the building. Where joints can be reached safely, we’ll do them. Give us some details and we will confirm the access.
What sealant do you use?
It depends on the joint: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. Brands we use include Arbo and Everbuild.
How much does external mastic cost in Tonwell?
Every job is different, so each one gets its own quote. To get one, call 0345 464 0079 or drop us an email and tell us what needs doing and where.
How we quote for external mastic
There’s no set price list, because no two jobs are the same. What we look at:
- Mould in or behind the old joints
- How many areas need sealing
- The number and length of the joints
- The product the joint needs
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please ring 0345 464 0079 or send us an email and we will 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:
- Where the job is, and your postcode
- If someone has resealed it before
- What the problem is, such as mould, gaps, leaks or cracking
- How many joints, rooms or windows are involved
It all starts with a short chat. Describe the problem, the location and the size of the job, and we’ll talk you through what we’d do. When it suits you, ring 0345 464 0079 or send us an email.
DIY versus a professional finish
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions.
How to look after the new joints
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Keep movement joints as flexible joints, not mortar
- Check external joints each spring
- Have failed joints looked at early
- Tell anyone working on the walls about the movement joints
Avoid pressure-washing straight into the joints. A strong jet can damage the edges of the bead and let water in behind.
An open movement joint lets rain into the wall every time it pours. That can lead to damp patches, staining and frost damage, all bigger jobs than a reseal.
Walls and rooflines in Tonwell
Compared with the north and west, the South East gets less rain, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. With historic houses such as Aston Bury (about 4.6 miles north-west) nearby, there’s older building stock in the area around Tonwell as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
If you look after a building such as Tonwell St Mary's Church of England Primary School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. Letting a property close to Ware station? Then outside joints that have cracked can let damp into a rental, so check them between lets.
Tonwell is about 2 miles north-west of Ware, in Hertfordshire. Homes, rented property, offices and hotels in Tonwell can book us for external mastic. The work is guaranteed for a year. Tonwell is one of 381 places in Hertfordshire where we work. Our London page covers work nearby, about 23 miles away.
We work across SG12 for external mastic and the streets around it. Whether your property is on Ware Road, Temple Lane and Bourne Honour or a nearby road, we can help. If you are just outside Tonwell, we cover Chapmore End (1 mile south), Sacombe (1 mile north), Thundridge (2 miles east), Wadesmill (2 miles east) and Sacombe Green (2 miles north). Larger places within reach include Stevenage (7 miles north-west), St Albans (13 miles south-west), Bishop's Stortford (10 miles east), Welwyn Garden City (6 miles south-west), Harpenden (12 miles west) and Hitchin (12 miles north-west).
Local landmarks in Tonwell
Around Tonwell, our work takes us to homes and buildings near Robin Hood & Little John pub and Chauncy School. Tonwell’s nearest station is Ware station, about 2.5 miles south-east of the centre. Nearby you will also find Hertford County Hospital (3 miles south) and Barrowfield (2.7 miles south). For a walk, there’s King's Meads.