Greater London · England
Bexley External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Bexley and across Greater London. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Weathered mastic that no longer stretches
- Damp patches traced to an open external joint
- Rigid filler in a joint that should flex
External mastic for homes and businesses in Bexley
A movement joint is a deliberate break that lets a wall expand and contract. Its sealant has to flex with the building, season after season, and when it fails, the wall takes the strain and water finds a way in. If you have moss and dirt in joints with no sealant left and water getting into walls through failed joints, we can put it right, on concrete & block, joints between brick and frames and render & cladding joints alike.
Newer London blocks are built with movement joints in brick and render, and with cladding joints sealed with mastic. Older terraces have their own weak points: gutter joints, roofline trims and the joint where an extension meets the original wall.
A 12-month guarantee comes as standard, so you are not left on your own once the job is done.
- Where
- Bexley (DA5, DA6, DA14, DA1)
- Region
- Greater London
- Guarantee
- One year on every job
- Quotes
- A clear price before we start
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
DIY versus a professional finish
A DIY attempt doesn’t rule out a professional job. We cut it out and start again.
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.
What external mastic looks like in Bexley
In terraces and conversions, gutters and walls are often shared with the neighbours, so check who is responsible for the outside before booking. 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.
If you let a flat or house near Bexley station, failed wall and movement joints let damp in, so they’re worth checking between tenancies. As a London address, Bexley can be tricky for parking: let us know about parking bays, permits or a driveway.
Bexley is about 3 miles east of Eltham, in Greater London. Anywhere in DA5, our applicators can take on external mastic. Across Greater London, we cover 764 places, and Bexley is one of them. We also work in London, around 11 miles away.
Our applicators cover all of DA5, DA6, DA14 and DA1 for external mastic. Whether your property is on Bexley High Street, Camden Road and The North Glade or anywhere close by, we can help. You’ll find Bexley on the A2018 and B2210, which makes it straightforward to reach with everything needed for external mastic. Close by, we work in Blendon (1 mile north-west), North Cray (1 mile south), Bexleyheath (1 mile north), Upton (1 mile north) and Coldblow (1 mile east). Within a short drive, we also cover London (11 miles west), City of Westminster (13 miles west), Marylebone (13 miles north-west), Kensington (15 miles west), St Pancras (12 miles north-west) and Shoreditch (11 miles north-west).
Local landmarks in Bexley
Around Bexley, our work takes us to homes and buildings near St Columba's Catholic Boys' School, Danson Park and Townley Grammar School, among other places. The nearest railway station is Bexley station, about 0.6 miles east of the centre. A little further out are Broadway Shopping Centre (1 mile north-east) and Bexley Museum (1.1 miles east). Open spaces near Bexley include Summer Hill and Wansunt Pit.
What the job involves on each surface
Cladding and façade panels
Metal and composite panels move a lot with temperature, so the joint sealant has to cope with frequent movement. We choose the product to suit.
Render joints
Cracks along render joints let water in behind the coat. A sound joint keeps the render dry behind.
What affects the cost of external mastic
Some jobs are bigger than they look, and some smaller. The main factors:
- Whether the work is at height
- How much old sealant there is and how hard it is to remove
- How much there is to do
- Any mould that needs treating
Rather than a set price list, we look at what your job involves: the amount of work, the old material and the access. You will know the price before we begin.
Helping us quote
The more you tell us, the more accurate the quote. When you get in contact, it helps to mention:
- Any previous sealing or DIY work
- A few pictures by email, if you can
- The type of property
- Where the job is, and your postcode
There’s no standard price list, as no two jobs are quite the same. Instead, we give you a clear quote for your job. To get started, ring 0345 464 0079 or drop us an email.
Common questions in Bexley
Do you cover Bexley for external mastic?
Yes, Bexley is within the area we cover. Our work covers London and the South East. Just phone 0345 464 0079 or drop us an email with a few details of the job.
Is parking an issue for external mastic in Bexley?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot, so mention what’s available when you book.
Can you seal joints between render and window frames?
Yes. Where different materials meet is one of the most common joints we seal. We use a flexible sealant suited to both surfaces, primed where needed.
Are you insured?
Yes. We are fully insured for every job we do.
How long should I leave it?
That depends on the sealant used, so please follow the time we give you.
Will you leave a mess?
Not at all. We work neatly, protect the area around the joints and tidy up afterwards.
How long does external mastic last?
That depends on the wall, the weather and the movement. Signs to watch for are cracking, hardening and gaps at the edges and have them redone then.
Where are you based?
We’re based in Crawley, and we work across South East England, London and Scotland.
How it works
When we arrive, we look over the joints with you first, so you know exactly what we’re doing. Surfaces next to the work are protected before any work starts. The work usually takes a few hours for a handful of joints, longer for a whole elevation. In Bexley, flats, stairs and shared entrances are part of the routine. Mention any building rules, key holders or managing agents when you book.
- We look at every joint and agree a colour to suit the wall.
- Failed sealant is removed back to clean, sound faces.
- Backing rod goes in so the sealant can stretch between the two faces.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
How to prepare
- Let us know about stairs, lifts or work at height
- On commercial sites, let us know about site rules
- Where the joints are inside, avoid wetting them before we arrive
Getting a quote
Need a quote? Please ring 0345 464 0079 or send us an email and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.
Advice
Places near Bexley
More services for Bexley
What we are called out for in Bexley
Sunlight, wet weather and frost wear exterior sealant down. Over the years it hardens, cracks on the surface and loses its give, so the joint eventually tears or comes away from one side.
Keep an eye out for these signs:
- Gaps where render, brick and frames meet
- Weeds or debris growing in open joints
- Rain getting behind render or cladding at a joint
- Joints pointed up with cement by mistake
Managing a site like Old Bexley Church of England School? Then larger buildings have long runs of movement joint that eventually need resealing.
Questions to ask before booking
- Whether they’re fully insured
- Whether the sealant suits the joint
- Whether all the old sealant comes out first
- What the quote includes, VAT included or not
What happens if it’s left?
A failed movement joint lets water into the wall and can run behind render or cladding. Dealing with it early keeps the repair to the joint, instead of the wall and finishes around it. 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.
We do not show prices on the website, because each job is priced on what it involves. For a quick quote, please call 0345 464 0079 or drop us an email and we will talk you through it.
Why book with us
- Over 20 years’ experience
- You choose the colour before work begins
- Quality sealants from Arbo and Everbuild
- Old sealant always removed completely
See our cost guide and customer reviews.
When it isn’t the sealant
Honest advice matters more to us than a booking, so here’s what sealant can’t fix:
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Cracked brickwork or render that needs a builder or plasterer
- Failed render or damaged cladding panels
If you are not sure, just call 0345 464 0079 or drop us an email and we’ll give you a straight answer.
What we seal
- Joints between brick and frames
- Brickwork movement joints
- Concrete & block
- Copings & trims
- Render & cladding joints
- Façade panels