Greater London · England
The Hyde External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in The Hyde and across Greater London. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Joints where the bead has come unstuck
- Moss and dirt in joints with no sealant left
- Hard, crazed mastic that has stopped moving
External mastic in The Hyde
Where two different materials meet, such as brick and render or blockwork and metal, they move at different rates. A flexible sealant bridges the two where mortar or filler would crack. If you are dealing with water getting into walls through failed joints and leaking joints around cladding and façade panels, we can help.
Working on the outside of a London home means planning access: shared paths, upper floors and parking. For a home in The Hyde, tell us how high the joints are and how to reach the back of the building.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we’ll put it right.
- Place
- The Hyde (NW9, NW4)
- Wider area
- Greater London
- Guarantee
- One year on every job
- Quotes
- A clear quote up front
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Why deal with it now?
Done well, a resealed joint is a neat, straight line that suits the wall. A rushed bead with no backing looks untidy and doesn’t last. Damp from a failed joint spreads quietly in older London brickwork and timber, and once it shows in The Hyde, the repair is bigger than a sealant job.
The cost depends on the size of the job, how hard the old material is to remove and how easy the joints are to reach. We give a clear quote before any work starts, so you know where you stand.
Why The Hyde customers choose us
- Any old sealant cut out fully, not covered over
- A choice of colours where the product allows
- Experience in homes, commercial sites and hotels
- Tidy, careful work
Read our cost guide and customer reviews.
When to call us in The Hyde
Sometimes a movement joint was filled with mortar or a rigid filler, often by someone who didn’t know what it was for. The joint cannot move, so the wall cracks somewhere else instead.
The problems people generally mention when they call are:
- Moss and dirt in joints with no sealant left
- Panel joints letting water in
- Old sealant gone brittle and cracked
- Joints with sealant missing in places
For landlords with property near Hendon station, outside joints that have cracked can let damp into a rental, so check them between lets.
Comparing quotes
- How much experience the applicator has
- Whether the sealant suits the joint
- Which colour the sealant will be
- How hidden problems are handled
Honest limits
We’ll always be straight with you, so here’s what new sealant will not do:
- Cutting new joints into brickwork, which is building work rather than sealant work
- Structural movement, which needs a surveyor or engineer
- Cracks in the bricks or render themselves, away from the joints
If you are not sure, just call 0345 464 0079 or drop us an email and we will give you a straight answer before booking.
Surfaces we seal
- Joints between brick and frames
- Render & cladding joints
- Concrete & block
- Brickwork movement joints
- Copings & trims
- Façade panels
Common questions in The Hyde
Can you help a landlord with a rental near Hendon station?
Yes, rental work is part of what we do. Just phone 0345 464 0079 or drop us an email and tell us about the property, and we’ll send you a clear quote.
Is The Hyde in your area for external mastic?
Yes, The Hyde is within the area we cover. We work across 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 send you a clear quote.
Where is Mr Mastic based?
Mr Mastic is based in Crawley. We cover The Hyde and the rest of Greater London, along with the rest of our area.
What does external mastic cost?
Every job is different, so each one gets its own quote. For a quick quote, ring 0345 464 0079 or email us with a short description of the job.
How often do external joints need resealing?
That varies with the weather the wall faces, how much it moves and the sealant used. Sealant is a maintenance item, so check the joints once a year and reseal when it splits.
What information do you need?
A short description and the location, plus photos if you have them. We will ask anything else we need to know.
Should I point up the gap in my brickwork?
No. A mortar-filled joint cannot move, so the movement cracks the wall elsewhere. Use a flexible sealant with backing rod.
What colours does the sealant come in?
The aim is a neat, even joint in a colour that suits the wall. Colour is agreed with you before we begin from the range available.
DIY sealant or a professional job?
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions, then guaranteed for a year.
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
Also near The Hyde
More services for The Hyde
Quotes for external mastic in The Hyde
Jobs vary more than people expect. The main factors:
- Whether the work is at height
- Whether old sealant or filler has to be cut out
- The type of sealant required
- The number and length of the joints
What you pay reflects the work, not guesswork. That’s why we ask about the job first.
Helping us quote
To make quoting easier, let us know:
- Access, such as stairs, a lift or height
- The address or postcode of the job
- A few pictures by email, if you can
- Whether it’s a home or a business
Call for a quick quote, or email us if that is easier. Tell us about the joints that need doing and we’ll talk you through the work and give you a clear quote.
Looking after it afterwards
A little care helps the new joints last. We recommend:
- Keep water from gutters off the wall
- Keep high-pressure jets off the joints
- Keep soil, plants and ivy away from the joints
- Look over the joints every year, ideally after winter
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.
Small splits are the time to act. Then it’s a straightforward cut-out and reseal.
What we do, step by step
Our applicators work methodically: protection first, then preparation, sealing and a tidy-up. For most jobs that takes a few hours for a handful of joints, longer for a whole elevation. For a job in The Hyde, parking and access are the things to plan: tell us about permits, visitor bays or off-street space, which floor we are working on and whether there’s a lift.
- 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.
- We gun in low-modulus sealant and tool it neatly.
Getting ready for the visit
- Where the joints are inside, avoid wetting them before we arrive
- Mention any leaks or damp you’ve noticed
- Tell us if parking is tricky
Get a quote
To get a quote, phone 0345 464 0079 or drop us an email with the location and a short description of the problem. We will give you a clear price before any work starts.
Read more
The Hyde buildings and the weather
Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Heath House (about 3.2 miles south-east) are a reminder that the area around The Hyde 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.
Managing a site like The Hyde School? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. The Hyde is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
The Hyde is about 2 miles north of Neasden, in Greater London. Jobs in The Hyde get the same care as everywhere else we work: old sealant removed completely, careful preparation and a one-year guarantee. The Hyde is one of 764 places in Greater London we cover. We also work in London, around 9 miles away.
All of NW9 and NW4 is covered for external mastic. Local streets include Alpini Road, Catkin Road and Garrick Road, all of which we cover. You will find The Hyde on the A5, so it’s easy for us to get to with everything needed for external mastic. If you are just outside The Hyde, we cover West Hendon (1 mile north), Colindale (1 mile north), The Burroughs (1 mile north-east), Hendon (1 mile east) and Staples Corner (1 mile south-east). Larger places within reach include London (9 miles south-east), City of Westminster (6 miles south-east), Marylebone (6 miles south-east), Kensington (6 miles south), St Pancras (7 miles south-east) and Shoreditch (8 miles south-east).
What’s near The Hyde
In The Hyde, that means homes and buildings near Moon Under Water pub, Brampton College and West Hendon Playing Fields and the streets around them. There’s a railway station in The Hyde itself: Hendon station. Nearby you’ll also find St Andrew's Hospital (1.5 miles south-east) and Church Farmhouse Museum (1.1 miles north-east). Green spaces nearby include Parliament Hill and Darland's Lake.