Hertfordshire · England
Heronsgate External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Heronsgate and across Hertfordshire. Fully insured, ARBOMaster approved and guaranteed for a year.
- Plants rooting in failed movement joints
- Gaps where render, brick and frames meet
- Joints where the bead has come unstuck
Honest limits
New sealant cannot fix everything, and we’d rather say so up front. It won’t solve:
- Cutting new joints into brickwork, which is building work rather than sealant work
- Damp that is not coming from the joint
- Cracks in the bricks or render themselves, away from the joints
If you are not sure, just ring 0345 464 0079 or email us and we will give you a straight answer before you book.
Joints and surfaces we work on
- Copings & trims
- Joints between brick and frames
- Brickwork movement joints
- Façade panels
- Render & cladding joints
- Concrete & block
External mastic in Heronsgate
On houses, flats and commercial buildings across Heronsgate, we reseal joints in brickwork, render, cladding and façade panels. Every joint gets the same careful preparation: clean joint faces and the right depth. If you’re dealing with sealant that has lost its bond to the brick or render and movement joints filled with mortar instead of sealant, we can help.
Outside joints can only be sealed when they’re dry, so work in Heronsgate is booked around the forecast. Let us know about access to every wall, plus any garages or outbuildings.
All of our work is guaranteed for twelve months, in Heronsgate and everywhere else we cover.
- Where
- Heronsgate (WD3)
- Wider area
- Hertfordshire
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Also near Heronsgate
More services for Heronsgate
Keeping the joints in good condition
Aftercare is simple, and it makes a real difference:
- Point out the joints to other trades
- Clear growth from the base of walls and joints
- Keep high-pressure jets off the joints
- Deal with leaking gutters that soak the joints below
Follow the cure time we give you before the joint is knocked or disturbed. The surface skins over quickly, but full cure takes longer.
Act while the splits are small. At that stage it’s a simple cut out and reseal.
Landlords, agents and businesses in Heronsgate
Housing providers, facilities teams and property managers book us too in Heronsgate and across Hertfordshire. We can quote a run of properties together, and we’re fully insured.
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we’ll quote.
FAQs for Heronsgate
Do you cover Heronsgate for external mastic?
Yes, Heronsgate is within the area we cover. We work across London and the South East. Just ring 0345 464 0079 or drop us an email with a few details of the job.
Can you help a landlord with a rental near Chorleywood station?
Yes. We work for landlords and agents as well as householders. Just call 0345 464 0079 or send us an email with the address and what needs doing, and we will send you a clear quote.
How often do external joints need resealing?
That depends on the wall, the weather and the movement. Signs to watch for are cracking, hardening and gaps at the edges, and reseal at that point.
Can you quote for more than one area?
Yes. Just list everything you need and we will quote it together.
Can you match the colour of my brickwork?
There’s a good range of exterior colours, including greys, browns, whites and stone tones. We pick the one that suits your wall best.
How do I get a quote for external mastic in Heronsgate?
The cost depends on the size of the job, access and how much old sealant has to come out. Ask us for a quote.
Do I need to be at home?
Access is agreed with you when the job is booked. Indoors, that usually means someone at home.
Can new sealant go over the old?
No, and we never do. It may look fine at first, but the new layer lifts away from the old one. Removing the old sealant completely is the only lasting way.
Outside joints around Heronsgate
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. Historic houses like Chenies Manor House (about 2.4 miles north) are a reminder that the area around Heronsgate has older buildings as well as new. Where a home is older, older brick and stone need a sealant that suits them, at the right joint depth.
If you look after a building such as Chorleywood Primary School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. Letting a property close to Chorleywood station? Then split movement joints are easy to miss on a rental until damp shows inside.
Heronsgate is about 1 mile south-west of Chorleywood, in Hertfordshire. Homes, rented property, offices and hotels in Heronsgate can book us for external mastic, old or new, large or small. The work is guaranteed for a year. 381 places in Hertfordshire are on our list. For nearby work, see our London page (21 miles or so).
Our applicators cover all of the WD3 postcode area for external mastic. We cover properties on Long Lane, Stag Lane and Halifax Road. Other places close to Heronsgate include Chorleywood (1 mile north-east), Maple Cross (1 mile south), Horn Hill (1 mile south), Chalfont Common (2 miles south-west) and West Hyde (2 miles south). We also work in nearby towns such as Watford (5 miles east), Hemel Hempstead (8 miles north), St Albans (11 miles north-east), Harpenden (14 miles north-east), Hatfield (15 miles north-east) and Borehamwood (11 miles east).
What’s near Heronsgate
Locally, jobs take us to homes and businesses close to Rickmansworth Aquadrome and the streets around them. The closest station to Heronsgate is Chorleywood station, roughly 1 mile north. Other landmarks nearby include Chiltern Open Air Museum (1 mile west) and Harefield Hospital (2.8 miles south-east). For a walk, there’s Chorleywood Common and Tumbling Bay.
DIY sealant or a professional job?
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
What affects the quote in Heronsgate
Call for a quick quote. The main things that affect it are:
- The number and length of the joints
- Whether there’s mould to deal with
- When we can work, for business premises
- Whether old sealant or filler has to be cut out
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed. Ask us for a quote and we will explain what it covers.
Asking for a quote
There’s no need for technical detail. It helps if you can tell us:
- Where the job is, and your postcode
- The rough size of the job
- Access, such as stairs, a lift or height
- Pictures of the joints, sent by email
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.
What we are called out for in Heronsgate
UV, rain and frost all age exterior sealant. Over the years it hardens, cracks on the surface and loses its give, so the joint eventually tears or comes away from one side.
Common reasons people contact us are:
- Cracked joints where brick meets render or frames
- Water getting into walls through failed joints
- Weeds or debris growing in open joints
- Panel joints letting water in
Homes close to St John include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain.
Before you book anyone
- Whether they seal over old material or remove it
- How the joint is cleaned and prepared
- Whether you can choose the colour
- What insurance they hold
How it works
There isn’t much for you to do on the day. Point us to the joints and we will get on with it. The job generally takes a few hours for a handful of joints, longer for a whole elevation. In a small place like Heronsgate, access is usually the main thing to plan. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- Each joint is checked and the colour of the new sealant agreed.
- We take out the old sealant until the faces are sound.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
How to prepare
- Mention any sign-in or site rules at work premises
- Mention any parking rules near the property
- Mention if the joints have been sealed before
Getting a quote
Call for a quick quote, or send an email if you’d rather. Tell us about the joints that need doing and we’ll explain what’s involved before giving you a price.