Greater London · England
External & façade joints in Mill Hill, Greater London
Movement joints in Mill Hill need attention? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Rigid filler in a joint that should flex
- Brick movement joints where the sealant has split
- Weathered mastic that no longer stretches
External mastic in Mill Hill, done properly
We are ARBOMaster approved applicators, and each external joint gets a sealant suited to it. Some surfaces need a primer before sealing and we use one wherever it does. If you’re dealing with sealant pulling away from one side of the joint and brick movement joints where the sealant has split, we can put it right, whatever the surface.
Working on the outside of a London home means planning access: shared paths, upper floors and parking. For a home in Mill Hill, tell us how high the joints are and how to reach the back of the building.
Whatever the size of the job, it’s backed by our 12-month guarantee in Mill Hill and across Greater London.
- Location
- Mill Hill (NW7, N20)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Quote
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Mill Hill buildings and the weather
London terraces and converted houses often share gutters, downpipes and walls, so check who is responsible for the outside before booking. Historic houses like Heath Hall (about 4 miles south-east) are a reminder that the area around Mill Hill 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.
For an older house near a landmark such as St Paul's Church, old and new materials meet at the roofline and walls, which is where sealant earns its keep. Managing a site like St Paul's CofE Primary School NW7? Then its movement joints, gutters and trims need looking after like any other building’s.
Mill Hill is about 1 mile north-east of Burnt Oak, in Greater London. We carry out external mastic for homeowners, landlords and businesses in Mill Hill and the surrounding area. Mill Hill is one of 764 towns and villages in Greater London where we work. We also work in London, around 10 miles away.
Every address in NW7 and N20 is covered for external mastic. That includes homes and businesses on Daws Lane, Byron Road and High Street. Neighbouring places we cover for external mastic include The Hale (1 mile west), Burnt Oak (1 mile south-west), Grahame Park (1 mile south), Totteridge (2 miles north-east) and Edgware (2 miles west). Within a short drive, we also cover London (10 miles south-east), City of Westminster (8 miles south-east), Marylebone (8 miles south-east), Kensington (8 miles south), St Pancras (8 miles south-east) and Shoreditch (9 miles south-east).
What’s near Mill Hill
In Mill Hill, that means homes and buildings near Mill Hill School, Copthall School and Bittacy Hill Park. Other local landmarks include Francis Skaryna Belarusian Library and Museum (2 miles east) and Rising Sun pub (0.7 miles north-west). The closest station to Mill Hill is Mill Hill Broadway station, about 1 mile south-west. Nearby you will also find Broadwalk Centre (2 miles west) and Francis Skaryna Belarusian Library and Museum (2 miles east). Not far away are The Mill Field and Darland's Lake.
Keeping the joints in good condition
Simple care keeps the joints in good condition. We recommend:
- Avoid pressure-washing directly into sealant joints
- Tell anyone working on the walls about the movement joints
- Keep soil, plants and ivy away from the joints
- Keep movement joints as flexible joints, not mortar
Only paint over the joint if we’ve confirmed the sealant can take paint. Many exterior sealants aren’t designed to be painted, and paint can crack as the joint moves.
Once a joint can’t move, the wall finds another way, usually as cracking in the brickwork or render nearby. Resealing it early helps prevent that.
Mill Hill questions
Can parking be tricky for a visit in Mill Hill?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. That way the visit can be planned around it.
Can you help a landlord with a rental near Mill Hill Broadway station?
Yes, landlords and agents are among the people we work for. Just call 0345 464 0079 or email us with the address and what needs doing, and we will send you a clear quote.
Will there be a smell?
Possibly a little. Any smell clears as the sealant cures.
Which products do you use?
Each joint gets the product that suits it. Where it moves, gets wet or faces the weather makes a difference, and we’ll tell you what we’re using.
When will the joints need doing again?
It varies from wall to wall: joints on exposed walls or with a lot of movement age sooner. A yearly look will tell you when they need doing. Our work comes with a one-year guarantee.
Is the work guaranteed?
Yes, always. Each job is guaranteed for twelve months, wherever you are.
Can I do it myself?
Some simple jobs can be done by a careful DIYer. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
How do I get a quote for external mastic in Mill Hill?
We don’t publish prices, because the cost depends on the job: its size, the old material, access and the product needed. We agree the price before any work begins.
What affects the quote in Mill Hill
You will get a clear quote before work begins. It takes into account:
- Whether there’s mould to deal with
- Working hours on commercial sites
- Whether the work is at height
- The size of the job
What you pay reflects the work, not a rough estimate. That’s why we ask about the job first and agree the price before starting.
What to tell us for a quote
The more you tell us, the more accurate the quote. When you get in contact, it helps to mention:
- How many joints, rooms or windows are involved
- A few pictures by email, if you can
- Whether it’s a home or a business
- The problem you’ve noticed
We quote each job on its own, so start by telling us what you need. Simply ring 0345 464 0079 or email us and describe the job.
The process
We work through the job in order: 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. In Mill Hill, flats, stairs and shared entrances are part of the routine. If the building has a concierge, managing agent or access rules, tell us when you book.
- First, the joints are inspected and the access agreed.
- Every bit of old sealant and any mortar or debris is cut out.
- The faces are brushed clean and primed where the product requires it.
- We fit closed-cell backing rod to control the depth.
- The exterior sealant is applied, tooled and checked along its length.
Before we arrive
- Tell us about any previous sealing or DIY attempts
- Mention any leaks or damp you’ve noticed
- Keep children and pets away from the work area
Getting a quote
For external mastic in Mill Hill, phone 0345 464 0079 or email us. A short description of the job and where it is helps us quote, and we’ll agree the price before any work begins.
Related advice
Why deal with it now?
Mortar or ordinary filler might look like a quick way to close an open joint, but it locks the joint solid. The wall then cracks somewhere else. The correct repair is a flexible sealant with the right backing. In a flat in Mill Hill, failed sealant seldom stays inside your own four walls: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
Every job is a little different, so each one gets its own quote. Size, access and the product the joint needs all make a difference.
Why choose Mr Mastic in Mill Hill
- Experience in homes, commercial sites and hotels
- Fully insured
- ARBOMaster approved applicator
- 20+ years of sealant experience
See our cost guide or customer reviews.
How the job changes by surface
Copings and trims
Joints in copings, parapets and trims are exposed to the worst of the weather. Each is resealed with a weatherproof, flexible sealant.
Render joints
Render is weaker at the surface than brick, so a sealant that stretches easily protects the edges. We prime where the product needs it.
DIY versus a professional finish
The biggest DIY mistake is sealing over old sealant. New silicone won’t bond to old, so it lifts and traps water and mould underneath. All the old material has to come out first.
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, then guaranteed for a year.
What we are called out for in Mill Hill
Buildings move more than people expect. Brickwork grows a little over the years, blockwork and concrete shrink, and all of it moves with heat and moisture. All of that ends up in the joint sealant.
If you can see any of these, it’s time to have the joints looked at:
- Movement joints filled with mortar instead of sealant
- Hard, crazed mastic that has stopped moving
- Movement joints with cracked, split or missing sealant
- Cracked joints where brick meets render or frames
Mill Hill is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Before booking anyone
- What happens if the job turns out different
- How the colour is chosen
- How long the guarantee is
- Is the old sealant removed completely?