Hertfordshire · England
External & façade joints in St Leonards, Hertfordshire
Problem with your movement joints in St Leonards? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Leaking joints around cladding and façade panels
- Failed seals between different materials
- Sealant that has lost its bond to the brick or render
About our external mastic in St Leonards
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 use one wherever it does. Typical jobs include rain getting behind render or cladding at a joint and brick movement joints where the sealant has split, across façade panels, concrete & block and render & cladding joints.
Somewhere as small as St Leonards, 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.
Big or small, it’s backed by our 12-month guarantee.
- Place
- St Leonards (HP23)
- Region
- Hertfordshire
- Cover
- A year, on every job
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Looking after it afterwards
Good habits help new joints last longer. A few tips:
- Check the sealant is paintable before painting near it
- Wash walls gently around the sealant
- Make sure movement joints are not pointed over
- Do not let climbing plants root in the sealant
Only paint over the joint if we have confirmed the sealant can take paint. Paint can crack on a flexible joint and spoil the finish.
Leave a failed movement joint and water keeps getting into the wall. Over time it can mean damp inside, stained render or frost-damaged brick, all bigger jobs than a reseal.
Places near St Leonards
What else we do in St Leonards
DIY sealant or a professional job?
The biggest DIY mistake is sealing over old sealant. Silicone doesn’t stick to old silicone, so it peels away and traps moisture behind it. All the old material has to come out first.
If you’ve already had a go yourself, that is fine. We remove it and do the joint properly.
The process
On the day, there’s very little for you to do. Show us the job and we’ll take it from there. The work itself takes a few hours to a few days, depending on the length of joint and the access, including the tidy-up. For a village or hamlet like St Leonards, the journey is planned in advance: let us know about lanes, gates and parking. We bring what the job needs, so it can be finished in one trip 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.
How to prepare
- For indoor joints, keep the area dry beforehand if you can
- Mention if the joints have been sealed before
- Clear items away from the joints we are working on
Ask for a quote
If you’re in St Leonards and need external mastic, ring 0345 464 0079 or email us. A short description of the job and where it is helps us quote, and you’ll get a clear quote before work begins.
Advice
For landlords and businesses
We also work for property managers and facilities teams. We can quote a run of properties together, and we are fully insured for the work.
We work for letting agents and landlords as well as homeowners. Sealant work between tenants keeps a property looking cared for before the next move-in.
How the job changes by surface
Render joints
Water behind render can lead to blown patches. A sound joint keeps the render dry behind and helps it last.
Joints between dissimilar materials
Different materials may need different primers. We prepare both faces so the sealant bonds properly.
What external mastic looks like in St Leonards
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. Historic houses like Cholesbury Manor House (about 1.1 miles east) are a reminder that the area around St Leonards has older buildings as well as new. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material.
For landlords with property near Wendover station, failed wall and movement joints let damp in, so they’re worth checking between tenancies. Homes close to Church of St Leonard include some older properties, and older walls, gutters and the joints where extensions meet them need a flexible sealant.
St Leonards is about 4 miles north-west of Chesham, in Hertfordshire. Jobs in St Leonards get the same care as everywhere else we work: old sealant removed completely, careful preparation and a one-year guarantee. We cover 381 towns and villages across Hertfordshire, from the larger towns to small villages. Our Oxford page covers work nearby.
We work across HP23 for external mastic. That includes homes and businesses on Bottom Road, Gilbert's Hill and Jenkins Lane. Neighbouring places we cover for external mastic include Buckland Common (1 mile east), Cholesbury (1 mile east), Hastoe (1 mile north), Swan Bottom (1 mile south-west) and Lee Common (2 miles south). Larger places within reach include Watford (14 miles south-east), Hemel Hempstead (9 miles east), St Albans (15 miles east), Harpenden (15 miles east), Berkhamsted (5 miles east) and Rickmansworth (12 miles south-east).
Around St Leonards
Typical jobs here are in homes near White Lion Public House, among other places. The nearest railway station is Wendover station, about 2.9 miles west. A little further out are Trenchard Museum (2.2 miles north-west) and Hawridge Court (2.5 miles south-east). For a walk, there’s Dancersend Nature Reserve and Pavis Wood.
What sealant work can’t fix
Before you book, it’s worth knowing the limits:
- Subsidence or other structural problems
- Failed render or damaged cladding panels
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
If you’re not sure, just phone 0345 464 0079 or send us an email and we’ll give you a straight answer before you book.
Joints and surfaces we work on
- Brickwork movement joints
- Concrete & block
- Render & cladding joints
- Copings & trims
- Façade panels
- Joints between brick and frames
What affects the quote in St Leonards
We don’t publish a price list. What we look at:
- Any working-time requirements on site
- Whether there’s mould to deal with
- The amount of work
- How easy the joints are to reach
Instead of a standard rate, we look at what your job involves: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
Helping us quote
You do not need to know the technical terms. Just tell us:
- Access, such as stairs, a lift or height
- If it’s domestic, commercial or a hotel
- Pictures of the joints, sent by email
- What the problem is, such as mould, gaps, leaks or cracking
We do not publish a price list. Instead, your job gets its own clear quote. To arrange one, ring 0345 464 0079 or drop us an email.
Your questions about external mastic in St Leonards
Do you cover St Leonards for external mastic?
Yes, St Leonards is within the area we cover. Our work covers London and the South East. You can phone 0345 464 0079 or drop us an email and let us know what needs doing.
Is St Leonards within the area you cover?
Yes, St Leonards is covered. 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.
Do you hold any approvals?
Yes. We’re ARBOMaster approved, the scheme for applicators of Arbo sealants.
Are you insured?
Yes. Full insurance covers our work, and we can confirm the details when we quote.
How long will you be here?
Most jobs take anything from a few hours to several days, depending on the building. Your quote will say how long we expect yours to take.
What is a movement joint?
Brickwork, render and cladding all move a little, and planned joints take up that movement. It’s closed with backing rod and a flexible sealant.
Do you remove the old sealant?
Always. Sealing over the old bead is the commonest cause of early failure, so we never do it.
Do I need to be at home?
We need access to the joints, so we will agree that with you when we book. Indoors, that usually means someone at home.