Hertfordshire · England
External Mastic in Aldenham
Our applicators work in Aldenham on sealing brickwork movement joints, render, cladding and façade joints. Old sealant removed completely, joints prepared properly.
- Failed seals between different materials
- Old sealant gone brittle and cracked
- Sealant that has lost its bond to the brick or render
About our external mastic in Aldenham
Joints in render and cladding are easy to overlook until a damp patch appears. We look over the joints, agree the ones to renew and reseal with a flexible, weatherproof product. If you have sealant that has lost its bond to the brick or render and joints pointed up with cement by mistake, we can help, on render & cladding joints, brickwork movement joints and copings & trims alike.
In a village or hamlet like Aldenham, older cottages and farm buildings often stand in the open, so walls and rooflines take the full force of wind and rain. Joints on those walls need a sealant that moves with the building and stays in place.
Your job is guaranteed for a year, as with all our work.
- Place
- Aldenham (WD25)
- Region
- Hertfordshire
- Cover
- 12 months on all our work
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Looking after it afterwards
To keep the joints looking good and working properly:
- Deal with leaking gutters that soak the joints below
- Tell anyone working on the walls about the movement joints
- Look over the joints every year, ideally after winter
- Keep movement joints as flexible joints, not mortar
Only paint over the joint if we have confirmed the sealant can take paint. Many exterior sealants are not designed to be painted, and paint can crack as the joint moves.
If you can see gaps, plants or bare sections in a joint, have it checked. Earlier resealing means a smaller job and a better result.
How the visit works
Our applicators work methodically: protect, prepare, seal, tidy. Typically it takes a few hours to a few days, depending on the length of joint and the access, and the area is left clean. Somewhere as small as Aldenham, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- We inspect the joints and agree which need resealing and how they’ll be reached.
- The old mastic and anything lodged in the joint is removed.
- Both sides are cleaned back to sound material and primed if needed.
- We push in closed-cell backing rod so the sealant is the right depth and bonds to the sides only.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
How to prepare
- Let us know if you’ve seen damp or leaks
- Let us know about earlier repairs to the joints
- Mention any parking rules near the property
Ask for a quote
For a quote, call 0345 464 0079 or drop us an email and tell us where the job is and what the problem looks like. We will send you a clear quote before any work starts.
Related advice
More services for Aldenham
Why it’s worth doing now in Aldenham
Sealing over the top of old mastic doesn’t hold for long. New sealant doesn’t bond well to old, weathered sealant, so the old joint is cut out fully first. Where a wall is exposed, as many are in small places like Aldenham, wind-driven rain gets into any failed joint, and older walls, once damp, take a long time to dry.
Combining jobs into one visit is usually more efficient than separate visits, so tell us about everything that needs sealing. We’ll give you a clear quote for the lot.
Why us?
- Tidy, careful work
- A sealant colour to suit the surroundings
- An ARBOMaster approved applicator
- 4.9 on Google from 180+ five-star reviews
Take a look at how sealant jobs are priced or what customers say.
Outside joints around Aldenham
With historic houses such as High Elms Manor (about 2.5 miles north-west) nearby, there’s older building stock in the area around Aldenham as well as newer homes. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth. 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 site and facilities teams at buildings such as Fair Field Junior School, its movement joints, gutters and trims need looking after like any other building’s. If you live in an older home near Church of St John the Baptist, an extension built onto an older house moves differently, and the joint between them takes the strain.
Aldenham is about 2 miles east of Watford, in Hertfordshire. Aldenham gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. We cover 381 towns and villages across Hertfordshire, large and small. You can also see our page for London, roughly 16 miles from Aldenham.
Here we cover the WD25 postcode area for external mastic. That includes homes and businesses on The Crescent, Red Lion Close and Church Lane and the roads around them. Neighbouring places we cover for external mastic include Round Bush (1 mile east), Patchetts Green (1 mile south), Kemprow (1 mile north-east), Letchmore Heath (1 mile south-east) and Meriden (1 mile west). Within a short drive, we also cover Hemel Hempstead (7 miles north-west), St Albans (5 miles north), Welwyn Garden City (11 miles north-east), Harpenden (10 miles north), Cheshunt (13 miles east) and Hatfield (8 miles north-east).
Landmarks near Aldenham
In Aldenham, that means homes and buildings near Three Compasses Public House, Garston Park and Queens' School, among other places. The closest station to Aldenham is Garston station, about 1.4 miles north-west. Other landmarks nearby include Hilfield Castle (1.7 miles south-east) and Watford General Hospital (2.8 miles south-west). The countryside around Aldenham includes Stanmore Common.
Landlord and commercial work in Aldenham
Businesses can book us for washrooms, kitchens, offices and more. For commercial premises, we can talk through working times when we quote.
Mouldy or split sealant often shows up at the end of a tenancy, and it’s quick to put right between tenancies. Several properties can be quoted together.
When to call us in Aldenham
Many joints fail because they were sealed too deep or with nothing behind them. Sealant bonded to three sides has nowhere to go and tears as soon as the joint widens.
Common reasons people contact us are:
- Cracked joints where brick meets render or frames
- Weathered mastic that no longer stretches
- Sealant pulling away from one side of the joint
- Rain getting behind render or cladding at a joint
Letting a property close to Garston station? Then outside joints that have cracked can let damp into a rental, so check them between lets.
Comparing quotes
- Which colour the sealant will be
- What guarantee comes with the work
- Whether the sealant suits the joint
- What the cure time is
FAQs for Aldenham
Do you cover smaller places like Aldenham?
Yes, smaller places are covered as well as towns. We work across London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Do you cover Aldenham for external mastic?
Yes, Aldenham is within the area we cover. Our work covers London and the South East. You can ring 0345 464 0079 or email us and let us know what needs doing, and we will give you a clear quote.
Is the work guaranteed?
Yes. All our work carries our 12-month guarantee.
Can you match the colour of my brickwork?
The sealant colour is picked to suit the wall. There’s a wide choice of exterior colours.
Can you reach joints on upper floors?
It depends on the height and the site. Ground-floor joints are simple; for higher ones, send details and we will confirm the access.
Where is Mr Mastic based?
We work from Crawley. We cover Aldenham and the rest of Hertfordshire, along with the rest of our area.
Do you do commercial work?
Yes. We work in offices, washrooms, hotels and other commercial premises, as well as homes. Working times can be discussed when we quote.
Will there be a smell?
Some sealants have a smell while they cure, which fades as it sets. Opening a window helps.
How we quote for external mastic
We don’t publish a price list, because no two jobs are the same. The quote depends on:
- How many areas need sealing
- Whether the work is at height
- Working hours on commercial sites
- The number and length of the joints
Commercial jobs are quoted on the same basis as homes: the amount of work, how we reach it and what it needs. Ask us for a quote and we will go through it with you.
Asking for a quote
Before you ask for a quote, have a think about:
- Any previous sealing or DIY work
- The problem you’ve noticed
- Roughly how big the job is
- Whether it’s a home or a business
The more we know about the job, the more useful the quote. Tell us where the job is, what’s wrong and how much there is, and email photos if that is easy.
What the job involves on each surface
Brickwork movement joints
Brick moves with heat and moisture, and grows a little over time. That movement goes into the joint, so its sealant has to stay flexible.
Joints between dissimilar materials
Where a frame or panel meets masonry, water often finds a way in. We cut out the old sealant and reseal with a product suited to both surfaces.