Hertfordshire · England
External & façade joints in Green Street, Hertfordshire
External mastic in Green Street from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Hard, crazed mastic that has stopped moving
- Movement joints filled with mortar instead of sealant
- Moss and dirt in joints with no sealant left
How we handle external mastic in Green Street
Low-level joints can generally be done from the ground. For joints higher up, give us some details of the building and we’ll confirm what’s needed to reach them safely. Common call-outs are for joints pointed up with cement by mistake and movement joints with cracked, split or missing sealant, on joints between brick and frames, copings & trims and façade panels.
Around Green Street, older buildings can be stone, brick or timber-framed, many with extensions added later. Where one material meets another is where water generally gets in.
The work is covered for a year after we finish. If there’s a problem with it, please ring 0345 464 0079 or drop us an email.
- Location
- Green Street (WD6)
- Region
- Hertfordshire
- Guarantee
- 12 months on all our work
- Quote
- A clear price before work begins
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Why deal with it now?
A failed movement joint lets water into the wall. Dealing with it early keeps the repair to the joint, rather than the wall around it. Older cottages and farmhouses around Green Street can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed, plus any working-time requirements on site. Ask us for a quote and we’ll go through it with you.
Why us?
- Anti-fungal sanitary silicone in wet areas
- 20+ years of sealant experience
- Rated 4.9 stars on Google
- A choice of colours where the product allows
Read what affects the cost or what customers say.
Aftercare tips
A little care helps the new joints last. Our advice:
- Point out the joints to other trades
- Look over the joints every year, ideally after winter
- Never let anyone fill a movement joint with mortar
- Clear growth from the base of walls and joints
Give the sealant the cure time we tell you before anything rubs against it. Most exterior sealants skin fast but take longer to cure right through.
Gaps, plants or missing sealant in a joint are worth getting looked at. Early work is quicker and leaves a better finish.
Your questions about external mastic in Green Street
Do you cover Green Street for external mastic?
Yes. Our work covers London and the South East, and Green Street is part of that. Just ring 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 Elstree & Borehamwood station?
Yes. We work for landlords and letting agents as well as householders, and several properties can be quoted together. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
Can you reach joints on upper floors?
That depends on the building and the joints. We work on joints that can be reached safely. Give us some details and we’ll confirm the access.
Where is Mr Mastic based?
Mr Mastic is based in Crawley. Our applicators cover Green Street, along with the rest of our area.
What information do you need?
Only a few details: where it is, what you’ve noticed and how we reach it. After that, simply phone 0345 464 0079 or drop us an email.
How much does external mastic cost in Green Street?
It depends on the job, so we quote each one individually. For a quick quote, phone 0345 464 0079 or email us with a short description of the job.
Which products do you use?
The product depends on the job: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. We use products from Arbo and Everbuild.
Does someone need to be in?
That depends on where the joints are. For work indoors, someone needs to let us in, and for outside work we will agree access with you when we book.
How we quote for external mastic
Your quote is based on your job. We look at:
- Any working-time requirements on site
- The size of the job
- Whether old sealant or filler has to be cut out
- Which sealant suits the joint
Combining jobs into one visit is normally more efficient than separate visits, so it’s worth mentioning everything you’d like done. We’ll give you a clear quote for the lot.
Asking for a quote
Photos by email are helpful but not essential. Try to tell us:
- Photos by email, if that’s easy
- What the problem is, such as mould, gaps, leaks or cracking
- Roughly how big the job is
- Where the job is, and your postcode
If you are in Green Street and need external mastic, ring 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and you’ll get a clear quote before work begins.
Places near Green Street
Also in Green Street
What sealant work cannot fix
Honest advice matters more to us than a booking, so here’s what new sealant won’t do:
- Cracking across the wall rather than at a joint
- Damp that isn’t coming from the joint
- Structural movement, which needs a surveyor or engineer
If in doubt, call 0345 464 0079 or send us an email and we will say what we think.
Surfaces we seal
- Façade panels
- Joints between brick and frames
- Brickwork movement joints
- Copings & trims
- Render & cladding joints
- Concrete & block
Landlord and commercial work in Green Street
Landlords and agents in Green Street can book us as well as homeowners. Resealing between tenancies keeps a property looking cared for.
Mouldy or split sealant often shows up at the end of a tenancy, and it’s easy to sort out between tenants. We can quote for more than one property at once.
What happens on the day
On the day, we start by going over the job with you, so there are no surprises. We protect the surfaces around the joints before any work starts. The work generally takes a few hours for a handful of joints, longer for a whole elevation. For a village or hamlet like Green Street, 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.
- Each joint is checked and the colour of the new sealant agreed.
- Failed sealant is removed back to clean, sound faces.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- Primer is applied wherever the sealant needs it.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Before we arrive
- Keep pets and children clear of the area while we work
- Tell us if parking is tricky
- Let us know about earlier repairs to the joints
How to get a quote
For a quote, call 0345 464 0079 or email us and tell us where the job is and what the problem looks like. We’ll send you a clear quote before any work starts.
Related advice
Walls and rooflines in Green Street
With historic houses such as Wyllyotts Manor (about 3.7 miles north-east) nearby, there’s older building stock in the area around Green Street as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. Rainfall in the South East is lower than in much 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 Parkside Community Primary School, larger buildings have long runs of movement joint that eventually need resealing. For landlords with property near Elstree & Borehamwood station, failed wall and movement joints let damp in, so they’re worth checking between tenancies. If you live in an older home near St Michael and All Angels Church, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Green Street is about 1 mile north of Borehamwood, in Hertfordshire. If you need external mastic in Green Street, it’s easy to get a quote: please phone 0345 464 0079 or drop us an email. We’re based in Crawley and cover Hertfordshire. We cover 381 towns and villages across Hertfordshire. For nearby work, see our London page (14 miles or so).
Here we cover the WD6 postcode area for external mastic. Local streets include Stapleton Road, Green Street and Cowley Hill, all of which we cover. If you’re just outside Green Street, we cover Well End (1 mile south-east), Borehamwood (1 mile south), Shenley (1 mile north-west), Ridge (2 miles north-east) and Rowley Green (2 miles south-east). Further out, we also cover Watford (5 miles west), Hemel Hempstead (10 miles north-west), St Albans (6 miles north-west), Welwyn Garden City (9 miles north), Harpenden (10 miles north) and Hoddesdon (12 miles north-east).
Near you in Green Street
Around Green Street, our work takes us to homes and buildings near The White Horse Public House and Hertswood Academy and the streets around them. The nearest railway station is Elstree & Borehamwood station, roughly 1.6 miles south of the centre. Well-known places in the area include Hilfield Castle (3 miles south-west) and Shenley Hospital (1.6 miles north-west). Open spaces near Green Street include Darland's Lake and Arkley Lane and Pastures.
Should I try it myself first?
If you’ve already had a go yourself, that’s fine. We cut it out and start again.
A careful DIYer can reseal a simple joint, 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.