Hertfordshire · England
External Mastic in Ayot Green
Professional external mastic in and around Ayot Green, with every bit of old sealant taken out first and a one-year guarantee.
- Sealant that has lost its bond to the brick or render
- Failed seals between different materials
- Weeds or debris growing in open joints
External mastic for homes and businesses in Ayot Green
As ARBOMaster approved applicators, we choose exterior sealants to suit the joint and the surfaces. Porous or awkward surfaces are primed where the sealant needs it, and we do not skip that step. We work on façade panels, concrete & block and brickwork movement joints, and people most often call us about gaps where render, brick and frames meet and weeds or debris growing in open joints.
Older homes in small places like Ayot Green may be stone, brick or timber-framed, often with later extensions. The joints where those materials meet are the weak points, and they need the right sealant at the right depth.
We guarantee the work for a year. If there’s a problem with our work within the year, let us know and we’ll sort it.
- Location
- Ayot Green (AL6, AL8)
- Wider area
- Hertfordshire
- Guarantee
- 12 months on all our work
- Quotes
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
How to look after the new joints
So the new joints stay in good condition:
- Clear growth from the base of walls and joints
- Avoid pressure-washing directly into sealant joints
- Leave the joints unpainted unless we’ve said otherwise
- Deal with leaking gutters that soak the joints below
Make sure anyone working on the wall later knows where the movement joints are. They should be kept open and resealed, not filled.
Gaps, plants or missing sealant in a joint are worth getting looked at. Earlier resealing means a smaller job and a better result.
When it is not the sealant
Before you book, it’s worth knowing the limits too:
- Damp that is not coming from the joint
- Movement that is more than a sealant joint can take
- Cutting new joints into brickwork, which is building work rather than sealant work
If you are not sure, just call 0345 464 0079 or drop us an email and we’ll give you a straight answer.
Where we work in Ayot Green
- Concrete & block
- Copings & trims
- Façade panels
- Joints between brick and frames
- Render & cladding joints
- Brickwork movement joints
What external mastic looks like in Ayot Green
Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. With historic houses such as Digswell House (about 1.1 miles east) nearby, there’s older building stock in the area around Ayot Green as well as newer homes. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material.
Homes close to Church of St Peter include some older properties, and older walls, gutters and the joints where extensions meet them need a flexible sealant. Schools such as Monk's Walk School are buildings too, and larger buildings have long runs of movement joint that eventually need resealing.
Ayot Green is about 2 miles north-west of Welwyn Garden City, in Hertfordshire. Homes, rented property, offices and hotels in Ayot Green can book us for external mastic, old or new, large or small. Every job comes with our one-year guarantee. 381 places in Hertfordshire are on our list. For nearby work, see our London page (22 miles or so).
We cover every part of AL6 and AL8 for external mastic and the streets around it. Local streets include Ayot St Peter Road, Ayot Green and Ayot Little Green Lane, all of which we cover. Neighbouring places we cover for external mastic include Ayot St Peter (1 mile north-west), Monkswood (1 mile north-east), Welwyn (1 mile north-east), Ayot St Lawrence (2 miles north-west) and Codicote (3 miles north). Within a short drive, we also cover Watford (13 miles south-west), Hemel Hempstead (11 miles south-west), Stevenage (7 miles north), St Albans (6 miles south-west), Harpenden (5 miles west) and Hitchin (10 miles north).
What’s near Ayot Green
Locally, jobs take us to homes and businesses close to Templewood Primary School, Danesbury Park and The Red Lion pub, among other places. Ayot Green’s nearest station is Welwyn Garden City station, roughly 1.4 miles south-east of the centre. A little further out are Queen Elizabeth II Hospital (2.8 miles south-east) and The Bunker at Hatfield Police Station (3.3 miles south). For a walk, there’s Lemsford Springs.
Also near Ayot Green
What else we do in Ayot Green
Can I do it myself?
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.
Sealing over old silicone is the commonest DIY error. Silicone doesn’t stick to old silicone, so it peels away and traps moisture behind it. Everything old must be removed first.
What happens on the day
All our tools and materials come with us in the van. After a quick look at the joints together, the area is protected and the work begins. It normally takes a few hours to a few days, depending on the length of joint and the access. Somewhere as small as Ayot Green, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- We start by walking round the building and agreeing the joints and the access.
- We cut out the old mastic and rake out anything in the joint.
- The faces are brushed clean and primed where the product requires it.
- We fit closed-cell backing rod to control the depth.
- The exterior sealant is applied, tooled and checked along its length.
Preparing for the visit
- Where the joints are inside, avoid wetting them before we arrive
- Tell us about access, such as stairs, a lift or high-level joints
- Clear items away from the joints we’re working on
Getting a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints.
Read more
What we are called out for in Ayot Green
Some movement joints have been pointed up with mortar, often by someone who didn’t know what it was for. With the joint locked solid, the movement turns into cracks elsewhere in the wall.
Common reasons people contact us include:
- Sealant that has lost its bond to the brick or render
- Rigid filler in a joint that should flex
- Panel joints letting water in
- Water getting into walls through failed joints
If you let a flat or house near Welwyn Garden City station, outside joints that have cracked can let damp into a rental, so check them between lets.
What your quote should include
- How the colour is chosen
- How hidden problems are handled
- Which sealant they’ll use, and why
- How long to leave it before use
What the job involves on each surface
Brickwork movement joints
People sometimes point up a brick movement joint by mistake. If that is happened, we rake it out and reseal it properly if the joint can be cleared.
Render joints
Water behind render can lead to blown patches. A sound joint keeps the render dry behind and helps it last.
Ayot Green: your questions answered
I let a flat near Welwyn Garden City station. Can you help?
Yes, rental work is part of what we do. Just ring 0345 464 0079 or email us and tell us about the property, and we’ll send you a clear quote.
Is Ayot Green within the area you cover?
Yes, we do. Our work covers London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Is it worth trying it myself?
It depends on the job. High-level, external movement and fire-rated joints are professional jobs, while a short indoor joint may be within reach.
How long will you be here?
As a guide, most jobs take anything from a few hours to several days, depending on the building. Bigger jobs take longer, and we’ll tell you how long to expect.
Is there any odour?
That depends on the sealant. Some products have a noticeable smell, others very little.
Do you take out the old sealant first?
Yes, always, and completely. New silicone doesn’t stick to old silicone, so the joint is cleaned back first.
Is the work guaranteed?
Yes. Every job comes with our one-year guarantee.
Can you quote for more than one area?
Yes. Just list everything you need and we’ll quote it together.
How we quote for external mastic
You will get a clear quote before work begins. It’s based on:
- The number of rooms or windows
- Access and height
- Whether old sealant or filler has to be cut out
- Working hours on commercial sites
Rather than a set price list, we price the job in front of us: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
What we need to know
What to tell us when you ask for a quote:
- Where the property is
- If someone has resealed it before
- The type of property
- Pictures of the joints, sent by email
We quote each job on its own, so the first step is telling us about yours. Simply phone 0345 464 0079 or send us an email and describe the job, and pictures are welcome.