Greater London · England
Finchley External Mastic
External mastic across Finchley and nearby, with old sealant always removed completely and a 12-month guarantee.
- Joints where the bead has come unstuck
- Hard, crazed mastic that has stopped moving
- Weeds or debris growing in open joints
External mastic in Finchley
We are ARBOMaster approved applicators, and each external joint gets a sealant suited to it. Porous or awkward surfaces are primed where the sealant needs it, and we do not skip that step. If you have plants rooting in failed movement joints and joints where the bead has come unstuck, we can put it right, whatever the surface.
In London terraces and converted houses, gutters and walls are often shared with the house next door, so a leaking gutter joint or failed wall joint can affect more than one home. For a flat in Finchley, check the lease for who looks after the outside.
A one-year guarantee comes with the work, just as it does everywhere we cover.
- Place
- Finchley (N3, N2, N12, NW11)
- Region
- Greater London
- Cover
- One year on every job
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Landlord and commercial work in Finchley
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance that we can handle for you.
If you manage several properties in or around Finchley, jobs at different addresses can go on one quote. Send us the addresses and the work at each.
How the visit works
Before we leave, we go over the finished joints with you and tell you how long to leave it. The work normally takes a few hours to a few days, depending on the length of joint and the access, depending on the size of the job. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Finchley. A visitor permit or a nearby bay makes the visit run more smoothly.
- 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.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Before we arrive
- Tell us if parking is tricky
- Mention any tricky access
- Clear items away from the joints we’re working on
Get a quote
Every job is quoted individually. Just ring 0345 464 0079 or send us an email with the details, and pictures are welcome.
Read more
Keeping the joints in good condition
Aftercare is simple:
- Have failed joints looked at early
- Check the sealant is paintable before painting near it
- Keep water from gutters off the wall
- Never let anyone fill a movement joint with mortar
Make sure anyone working on the wall later knows where the movement joints are. They should be kept open and resealed, not filled.
Once a joint can’t move, the wall finds another way, often as cracks near the joint. Catch it early and you reduce the risk.
When to call us in Finchley
If plants are growing out of a joint, the sealant has normally failed or was never there. Dirt and roots then trap moisture in the joint and make things worse.
The problems people usually mention when they call include:
- Hard, crazed mastic that has stopped moving
- Failed seals between different materials
- Sealant that has lost its bond to the brick or render
- Rigid filler in a joint that should flex
Schools such as Manorside Primary School are buildings too, and its movement joints, gutters and trims need looking after like any other building’s.
Comparing quotes
- Whether all the old sealant comes out first
- What happens if they find a problem under the old sealant
- How much experience the applicator has
- Are they insured?
Finchley questions
I let a flat near New Southgate station. Can you help?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. You can phone 0345 464 0079 or send us an email with the details for a clear quote.
Is parking an issue for external mastic in Finchley?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. The visit is then planned around what’s available.
What colours does the sealant come in?
The sealant colour is picked to suit the wall. Exterior sealants come in a good range of colours.
How do you reach high-level joints?
It depends on the building. Where joints can be reached safely, we’ll do them. Give us some details and we’ll confirm the access.
What is a movement joint?
Brickwork, render and cladding all move a little, and planned joints take up that movement. It’s closed with backing rod and a flexible sealant.
How long does the job take?
It depends on the size of the job, but most jobs take a few hours for a handful of joints, longer for a whole elevation. We will give you a better idea when we quote.
Do you seal joints where cladding meets other materials?
Yes. Where different materials meet is one of the most common joints we seal. The sealant is chosen to bond to both sides, primed where needed.
How often do external joints need resealing?
That varies with the weather the wall faces, how much it moves and the sealant used. Treat it as a maintenance item and look at it yearly.
Nearby places to Finchley
Also in Finchley
What affects the quote in Finchley
We do not publish a price list. The quote depends on:
- Whether old sealant or filler has to be cut out
- When we can work, for business premises
- Whether there’s mould to deal with
- The type of sealant required
Doing several joints on one visit generally makes better use of the time than several visits, so it’s worth mentioning everything you’d like done. You’ll get one clear quote for the whole job.
Helping us quote
What to tell us when you ask for a quote:
- Whether it’s a home or a business
- Access, such as stairs, a lift or height
- The rough size of the job
- Where the property is
For a quick quote, get us on the phone, or send an email if you’d rather. Tell us about the joints that need doing and we will explain what’s involved and send you a clear quote.
Different surfaces, different methods
Cladding and façade panels
Panels heat up and cool down quickly, so the joint sealant has to cope with frequent movement. The sealant is chosen with that in mind.
Concrete and blockwork
Big joints in concrete need careful depth control. Backing rod sized to the joint sets it.
What we can’t put right
We’ll always be straight with you, so here’s what sealant can’t fix:
- Adding movement joints to masonry that has none
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Subsidence or other structural problems
If in doubt, phone 0345 464 0079 or send us an email and we’ll say what we think.
What we seal
- Façade panels
- Brickwork movement joints
- Copings & trims
- Render & cladding joints
- Joints between brick and frames
- Concrete & block
What external mastic looks like in Finchley
With historic houses such as Heath Hall (about 1.8 miles south) nearby, there’s older building stock in the area around Finchley 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. In terraces and conversions, gutters and walls are often shared with the neighbours, so check who is responsible for the outside before booking.
As a London address, Finchley can be tricky for parking: let us know about parking bays, permits or a driveway. Rented homes near New Southgate station change hands often, and failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Finchley is about 6 miles north of City of Westminster, in Greater London. For external mastic in and around Finchley, it’s easy to get a quote: please phone 0345 464 0079 or send us an email. We are based in Crawley and cover Greater London, Finchley included. Our Greater London coverage runs to 764 places, Finchley among them. London is on our list too, about 8 miles from Finchley.
Postcode districts we cover here for external mastic: N3, N2, N12 and NW11. Whether your property is on Station Road, Chaplin Square and Market Place or a nearby road, our applicators can take on the job. Being close to the B1462, Finchley is simple for us to get to for external mastic. We also cover the places around Finchley: Church End (1 mile west), Woodside Park (1 mile north), North Finchley (1 mile north), Friern Barnet (2 miles north-east) and Oakleigh Park (2 miles north). Further out, we also cover London (8 miles south-east), City of Westminster (6 miles south), Marylebone (6 miles south), Kensington (7 miles south), St Pancras (6 miles south-east) and Shoreditch (7 miles south-east).
Near you in Finchley
In Finchley, that means homes and buildings near The Elephant Inn, Bishop Douglass School and Francis Skaryna Belarusian Library and Museum and the streets around them. Other local landmarks include Victoria Park (less than half a mile north) and Woodhouse College (1 mile north-east). For rail, the closest station is New Southgate station, about 1.9 miles north-east of the centre. Nearby you’ll also find Finchley Memorial Hospital (within half a mile north-east) and Grand Arcade (1 mile north). Open spaces near Finchley include Highgate Hill and Lakeside Nature Reserve.