Hertfordshire · England
Chandler's Cross External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Chandler's Cross and across Hertfordshire. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Failed seals between different materials
- Old sealant gone brittle and cracked
- Failed sealant between panels on a façade
External mastic in Chandler's Cross, done properly
Movement joints let brickwork, render and cladding expand and shrink without cracking. Its sealant has to flex with the building, season after season, and when it fails, the wall takes the strain and water finds a way in. Typical jobs include water getting into walls through failed joints and gaps where render, brick and frames meet, on façade panels, copings & trims and brickwork movement joints.
Older homes in small places like Chandler's Cross may be stone, brick or timber-framed, often with later extensions. Where one material meets another is where water generally gets in, and they need the right sealant at the right depth.
All our work is covered by our 12-month guarantee.
- Where
- Chandler's Cross (WD3)
- Wider area
- Hertfordshire
- Cover
- A year, on every job
- Quotes
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Should I try it myself first?
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
Nearby places to Chandler's Cross
More services for Chandler's Cross
Aftercare tips
No joint lasts for ever, but care makes a real difference. Our tips:
- Keep soil, plants and ivy away from the joints
- Check the sealant is paintable before painting near it
- Make sure movement joints aren’t pointed over
- Keep water from gutters off the wall
Don’t paint over the new sealant unless we’ve said the product is paintable. Many exterior sealants are not designed to be painted, and paint can crack as the joint moves.
Small splits are the time to act. Then it’s a straightforward cut-out and reseal before water has had years to get in.
Why it’s worth doing now in Chandler's Cross
Sealing over the top of old mastic doesn’t hold for long. The new layer cannot bond properly to old, weathered material, so the old joint is cut out fully first. In a small place like Chandler's Cross, homes can be exposed to wind and rain, which finds any gap, and older walls, once damp, take a long time to dry.
Doing several joints on one visit usually makes better use of the time than several visits. You will get one clear quote for the whole job.
Why Chandler's Cross clients choose us
- Fully insured
- Any old sealant cut out fully, not covered over
- Arbo and Everbuild products
- 20+ years of sealant experience
See our cost guide and our reviews.
External mastic in Chandler's Cross: local notes
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 Chenies Manor House (about 3.2 miles west) nearby, there’s older building stock in the area around Chandler's Cross 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.
Chenies Manor House, about 3.2 miles west, is one of the historic houses in the wider area around Chandler's Cross, and older homes nearby need a sealant that suits their walls. If you let a flat or house near Kings Langley station, split movement joints are easy to miss on a rental until damp shows inside. Schools such as York House School are buildings too, and its movement joints, gutters and trims need looking after like any other building’s.
Chandler's Cross is about 2 miles north of Rickmansworth, in Hertfordshire. We carry out external mastic for householders, landlords and businesses in Chandler's Cross and the surrounding area, as part of our work across Hertfordshire. Chandler's Cross is one of 381 places in Hertfordshire where we work. There’s also a page for London, roughly 20 miles from Chandler's Cross.
Jobs for external mastic in WD3 is quoted and booked the same way as anywhere else. Local streets include Chandler's Lane, White Shack Lane and Fir Tree Hill, and we cover them all. We also cover the places around Chandler's Cross: Micklefield Green (1 mile west), Bucks Hill (1 mile north-west), Loudwater (2 miles south-west), Sarratt (2 miles north-west) and Hunton Bridge (2 miles north-east). Further out, we also cover Watford (3 miles east), Hemel Hempstead (5 miles north), St Albans (8 miles north-east), Welwyn Garden City (14 miles north-east), Harpenden (11 miles north-east) and Hatfield (11 miles north-east).
What’s near Chandler's Cross
Locally, jobs take us to homes and businesses close to Croxley Danes School and the streets around them. Chandler's Cross’s nearest station is Kings Langley station, roughly 2.4 miles north. Well-known places in the area include Charter Place (2.9 miles south-east) and Watford General Hospital (2.9 miles south-east). Open spaces near Chandler's Cross include Chorleywood Common and Tumbling Bay.
What the job involves on each surface
Brickwork movement joints
Brick walls have vertical movement joints to absorb expansion. They’re resealed over backing rod with a low-modulus sealant coloured to suit the wall.
Cladding and façade panels
Panel systems often rely on sealant between and around the panels. We reseal them with a sealant suited to the panel material.
Common questions in Chandler's Cross
Can you do external mastic in Chandler's Cross?
Yes, Chandler's Cross is within the area we cover. Our work covers London and the South East. Just phone 0345 464 0079 or drop us an email with a few details of the job, and we will give you a clear quote.
Can you help a landlord with a rental near Kings Langley station?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. Just call 0345 464 0079 or send us an email with the address and what needs doing, and we will give you a clear price.
Is the work guaranteed?
Yes: twelve months. If anything is not right with the work within the year, let us know and we will sort it.
What colours does the sealant come in?
There’s a good range of exterior colours, including greys, browns, whites and stone tones. We pick the one that suits your wall best so it doesn’t stand out.
Is there any odour?
Some sealants have a smell while they cure, but it fades. Ventilation helps.
What information do you need?
The location, the problem and the rough size of the job. If you can, email a few photos.
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. We use products from Arbo and Everbuild.
What’s an expansion joint in brickwork?
It’s a deliberate gap that lets the wall expand and contract without cracking. It should be filled with flexible sealant, never mortar.
When it is not the sealant
We’d rather tell you now than do work that will not last, so these are the limits:
- Rising or penetrating damp from elsewhere in the wall
- Subsidence or other structural problems
- Render that’s blown, hollow or coming away
Not sure which it is? You can ring 0345 464 0079 or email us and we’ll tell you honestly.
What we seal
- Concrete & block
- Façade panels
- Copings & trims
- Render & cladding joints
- Joints between brick and frames
- Brickwork movement joints
What affects the cost of external mastic
Jobs vary more than people expect. What affects the quote:
- Whether the work is at height
- Whether there’s mould to deal with
- How much there is to do
- The old material and how stubborn it is
We do not show prices on the website, because the cost depends so much on the job itself. For a quick quote, please ring 0345 464 0079 or email us and we will talk you through it.
What to tell us for a quote
Photos by email are helpful but not essential. Try to tell us:
- Access, such as stairs, a lift or height
- A few photos by email, if you can
- Where the job is, and your postcode
- Whether it has been sealed before
There’s no standard price list, as no two jobs are quite the same. Instead, your job gets its own clear quote. To get started, phone 0345 464 0079 or email us.
What happens on the day
On the day, we start by going over the job with you, so you know exactly what we are doing. We protect the surfaces around the joints before we start. Most jobs take anything from a few hours to several days, depending on the building. For a village or hamlet like Chandler's Cross, the journey is planned in advance: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- First we look over the joints with you, agree which to renew and talk through access.
- 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.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
Preparing for the visit
- Let us know about parking restrictions
- Try not to wet indoor joints just before the visit
- Plan for the work area to be out of bounds to pets and children
Ask for a quote
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.