Greater London · England
External & façade joints in Barnehurst, Greater London
Our applicators work in Barnehurst on sealing brickwork movement joints, render, cladding and façade joints. Old sealant removed completely, joints prepared properly and every job guaranteed for a year.
- Rain getting behind render or cladding at a joint
- Leaking joints around cladding and façade panels
- Hard, crazed mastic that has stopped moving
Can I do it myself?
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
If you do try it yourself, take your time over the preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.
External mastic in Barnehurst, done properly
On houses, flats and commercial buildings across Barnehurst, 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 have joints where the bead has come unstuck and hard, crazed mastic that has stopped moving, we can help, 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. In a converted house in Barnehurst, it’s worth checking who is responsible for the outside before booking.
The work is guaranteed for twelve months. If something is not right with it in that time, tell us and we will put it right.
- Location
- Barnehurst (DA7, DA1, DA8)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Leave it or put it right?
An open joint keeps letting water into the wall with every downpour. Wet masonry is more easily damaged by frost, so the damage spreads beyond the joint. In a London flat, a failed joint rarely stays your problem alone: 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 we quote each one individually. The number of joints, how easy they are to reach and the sealant needed all play a part.
Why choose Mr Mastic in Barnehurst
- Approved under the ARBOMaster scheme
- We agree the colour with you first
- Old sealant always removed completely
- Trusted Arbo and Everbuild sealants
Read what affects the cost and customer reviews.
Common questions in Barnehurst
Can you do external mastic in Barnehurst?
Yes. We work across London and the South East, and Barnehurst is part of that. Just phone 0345 464 0079 or email us with a few details of the job, and we’ll send you a clear quote.
Is parking an issue for external mastic in Barnehurst?
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.
What is a movement joint?
Brickwork, render and cladding all move a little, so long walls have planned gaps to take that movement. The gap is sealed with a flexible sealant over backing rod.
Is there any odour?
Sometimes, a little. Any smell clears as the sealant cures, and ventilation helps.
Will the new joint stand out?
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.
Do you seal joints where cladding meets other materials?
Yes. Different materials move at different rates, so a flexible sealant is needed where they meet. The sealant is matched to both sides.
Which products do you use?
It depends on the joint: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. Brands we use include Arbo and Everbuild.
Do you work for letting agents?
Yes. As well as homeowners, we work for landlords, agents, businesses and hotels in Barnehurst.
Barnehurst buildings and the weather
With historic houses such as Hall Place and Gardens (about 1 mile south-west) nearby, there’s older building stock in the area around Barnehurst 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.
For landlords with property near Barnehurst station, outside joints that have cracked can let damp into a rental, so check them between lets. Managing a site like Mayplace Primary School? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. For an older house near a landmark such as Church of St Paulinus, older walls, gutters and the joints where extensions meet them need a flexible sealant.
Barnehurst is about 3 miles east of Welling, in Greater London. Barnehurst gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. Our area takes in 764 places across Greater London, large and small. For nearby work, see our London page, about 12 miles away.
Every address in DA7, DA1 and DA8 is within our area for external mastic, from the main roads to the quietest streets. Whether your property is on Old Road, Grove Road and Manor Road or a nearby road, our applicators can take on the job. You’ll find Barnehurst on the A2000, so it’s easy for us to get to. We also cover the places around Barnehurst: Bexley Riverside (1 mile north), Northumberland Heath (1 mile north), Crayford (1 mile south-east), North End (1 mile east) and Barnes Cray (1 mile east). Larger places within reach include London (12 miles west), City of Westminster (14 miles west), Marylebone (14 miles west), St Pancras (13 miles west), Shoreditch (12 miles north-west) and Walthamstow (12 miles north-west).
Local landmarks in Barnehurst
In Barnehurst, that means homes and buildings near St Catherine's Catholic School, St Catherine's Catholic School and Braeburn Park and the streets around them. The closest station to Barnehurst is Barnehurst station, about 0.5 miles north-west. Other landmarks nearby include Stone Castle (4.8 miles east) and Bexley Museum (1 mile south). Green spaces nearby include Wansunt Pit.
When it is not the sealant
To be straight with you, there are a few things sealant won’t fix:
- Walls that need new movement joints cut into them
- Movement that’s more than a sealant joint can take
- Rising or penetrating damp from elsewhere in the wall
Not sure which it is? You can call 0345 464 0079 or email us and we’ll tell you honestly before booking.
Joints and surfaces we work on
- Copings & trims
- Façade panels
- Brickwork movement joints
- Joints between brick and frames
- Render & cladding joints
- Concrete & block
Keeping the joints in good condition
After the cure time, these simple habits help:
- Keep high-pressure jets off the joints
- Leave the joints unpainted unless we’ve said otherwise
- Clear growth from the base of walls and joints
- Walk round the building once a year and look at the joints
Make sure anyone working on the wall later knows where the movement joints are. They must stay as flexible joints, never rendered or pointed over.
Leaks behind façade panels and render often go unseen. When it finally shows inside, the joint may have been open for years.
Towns and villages near Barnehurst
Other services in Barnehurst
The process
Every visit runs the same way: we check the joints, protect the area around them, carry out the job and clear up. It usually takes a few hours to a few days, depending on the length of joint and the access. In Barnehurst, 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.
- We look at every joint and agree a colour to suit the wall.
- 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.
- Primer is applied wherever the sealant needs it.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Preparing for the visit
- Try not to wet indoor joints just before the visit
- On commercial sites, let us know about site rules
- Mention if the joints have been sealed before
Getting a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and add photos by email if you can.
Read more
What affects the cost of external mastic
We don’t publish a price list, because no two jobs are the same. The quote depends on:
- Mould in or behind the old joints
- The product the joint needs
- How much there is to do
- How many rooms, windows or areas are involved
We don’t show prices on the website, because the cost depends so much on the job itself. For a quick quote, please call 0345 464 0079 or email us and we’ll talk you through it.
Asking for a quote
When you call or email, it’s useful to know:
- Where the property is
- Photos by email, if that’s easy
- Whether it’s a home or a business
- What the problem is, such as mould, gaps, leaks or cracking
Call for a quick quote, or email us if that’s easier. Tell us about the joints that need doing and we’ll talk you through the work and give you a clear price.
Landlord and commercial work in Barnehurst
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Keeping joints in good order is simple maintenance that we can handle for you.
Businesses can book us for washrooms, kitchens, offices and more. For commercial premises, we can talk through working times when we quote.