Greater London · England
External Mastic in Adelphi
Sealing brickwork movement joints, render, cladding and façade joints for householders, landlords and businesses in Adelphi. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Damp patches traced to an open external joint
- Panel joints letting water in
- Gaps where render, brick and frames meet
Adelphi: your questions answered
Can you do external mastic in Adelphi?
Yes. We work across London and the South East, and Adelphi is part of that. You can ring 0345 464 0079 or drop us an email and let us know what needs doing.
Can you help a landlord with a rental near London Charing Cross station?
Yes, rental work is part of what we do. You can call 0345 464 0079 or send us an email with the address and a few details, and we will give you a fixed price before any work starts.
Do you seal joints where cladding meets other materials?
Yes. The old joint is removed, both surfaces cleaned and primed where needed, and a flexible sealant applied. We pick a colour that works with both materials.
Is it OK to seal over old sealant?
No. We remove every bit of old sealant first.
Is it OK to fill a movement joint with cement?
No. A mortar-filled joint can’t move, so the wall cracks somewhere else instead. It needs a flexible sealant over backing rod.
Do the sealants smell?
It depends on the product. Some smell for a while, some hardly at all, and any smell fades as they cure.
What is a movement joint?
Most straight vertical gaps in brickwork are movement joints. It lets the bricks expand without cracking.
What sealant 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 will tell you what we are using.
About our external mastic in Adelphi
On houses, flats and commercial buildings across Adelphi, we reseal joints in brickwork, render, cladding and façade panels. The preparation is the same whatever the wall: clean, sound faces and a controlled depth. If you’re dealing with failed seals between different materials and plants rooting in failed movement joints, we can help, on joints between brick and frames, façade panels and copings & trims alike.
Working on the outside of a London home means planning access: shared paths, upper floors and parking. In Adelphi, joints up high may need ladders or other access, which is worth talking through when you book.
All of our work is guaranteed for twelve months, in Adelphi and everywhere else we cover.
- Location
- Adelphi (W1D, W1F, WC2H)
- Region
- Greater London
- Guarantee
- A year, on every job
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Nearby places to Adelphi
More services for Adelphi
Surface by surface
Joints between dissimilar materials
Brick against render, concrete against metal, stone against timber: every change of material is a joint. A flexible sealant bridges the two.
Copings and trims
Copings expand and contract through the day, so a flexible sealant suits them best.
Common problems we fix in Adelphi
UV, rain and frost all age exterior sealant. Over the years it hardens, cracks on the surface and loses its give, so the next time the wall moves, it splits or pulls away.
The problems people generally mention when they call include:
- Damp patches traced to an open external joint
- Gaps where render, brick and frames meet
- Leaking joints around cladding and façade panels
- Hard, crazed mastic that has stopped moving
Homes close to Savoy Chapel include some older properties, and old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Before booking anyone
- Which sealant they’ll use, and why
- How much experience the applicator has
- What happens if they find a problem under the old sealant
- What the quote includes, VAT included or not
What happens on the day
We bring everything the job needs with us, so there’s nothing for you to buy. Once we have agreed what’s being done, we protect the area and start. Most jobs take anything from a few hours to several days, depending on the building. In Adelphi, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- Each joint is checked and the colour of the new sealant agreed.
- Failed sealant is removed back to clean, sound faces.
- Backing rod goes in so the sealant can stretch between the two faces.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Getting ready for the visit
- Mention any sign-in or site rules at work premises
- Let us know about stairs, lifts or work at height
- Clear items away from the joints we are working on
Get a quote
For external mastic in Adelphi, call 0345 464 0079 or drop us an email. A short description of the job and where it is helps us quote, and we’ll agree the price before any work begins.
Read more
Outside joints around Adelphi
Compared with the north and west, the South East gets less rain, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. In terraces and conversions, gutters and walls are often shared with the neighbours, so it’s worth agreeing who is responsible before work starts.
Schools such as St Clement Danes CofE Primary School are buildings too, and its movement joints, gutters and trims need looking after like any other building’s. Rented homes near London Charing Cross station change hands often, and outside joints that have cracked can let damp into a rental, so check them between lets.
Adelphi is about 1 mile south-east of Marylebone, in Greater London. For external mastic in and around Adelphi, please phone 0345 464 0079 or send us an email for a quick quote. We’re based in Crawley and cover Greater London. Adelphi is one of 764 towns and villages in Greater London where we work for external mastic.
Jobs for external mastic in W1D, W1F and WC2H is quoted and booked the same way as anywhere else. External mastic is available to properties on York Road, Drury Lane and Maiden Lane. You’ll find Adelphi on the A301 and A400, which makes it straightforward to reach with everything needed for external mastic. We also cover Covent Garden (1 mile north), Charing Cross (1 mile south-west), Aldwych (1 mile north-east), Seven Dials (1 mile north-west) and West End (1 mile north-west). Larger places within reach include Kensington (3 miles west), Walthamstow (7 miles north-east), Hampstead (4 miles north-west), Ruislip (13 miles west), Stockwell (3 miles south) and Orpington (13 miles south-east).
Local landmarks in Adelphi
Locally, jobs take us to homes and businesses close to The BFI Reuben Library, St Andrew's and St John's Church of England Primary School and London Nautical School and the streets around them. Other local landmarks include Victoria Embankment Gardens (less than half a mile south) and The Theodore Bullfrog pub (under half a mile south-west). Adelphi has its own railway station: London Charing Cross station. Nearby you will also find London Museum and Institute of Natural History (less than half a mile north-east) and Montfichet's Tower (1 mile east). Open spaces near Adelphi include St. James's Park Lake and Barnsbury Wood.
How to look after the new joints
A little care helps the new joints last. Our advice:
- Check the sealant is paintable before painting near it
- Act on the first splits you see
- Keep soil, plants and ivy away from the joints
- Wash walls gently around the sealant
Keep the joints clear of soil, plants and climbing growth. Damp material against the sealant shortens its life.
Once a joint cannot move, the wall finds another way, often as cracks near the joint. Catch it early and you reduce the risk.
How we quote for external mastic
The quote reflects the job in front of us. We look at:
- Mould in or behind the old joints
- Any working-time requirements on site
- The old material and how stubborn it is
- Whether the work is at height
Some things make a job bigger or smaller: the old material and how easily it comes out, whether mould needs treating, and whether the work is at height. We take all of that into account in your quote.
What to tell us for a quote
What to tell us when you ask for a quote:
- Whether it’s a home or a business
- A few pictures by email, if you can
- Access, such as stairs, a lift or height
- The address or postcode of the job
For a quick quote, get us on the phone, or email us if that is easier. Tell us about the joints that need doing and we will explain what’s involved.
Can I do it myself?
Sealing over old silicone is the commonest DIY error. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. All the old material has to come out first.
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
What happens if it’s left?
Water gets in through a failed movement joint 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. Converted houses in London often have a bathroom above someone else’s living room, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler for homes in Adelphi.
The cost reflects the work involved, not a rough estimate. That’s why we ask a few questions first and agree the price before starting.
Why Adelphi clients choose us
- White, clear, grey or coloured to suit, where the product allows
- You choose the colour before work begins
- Over 20 years’ experience
- Any old sealant cut out fully, not covered over
Read our cost guide and customer reviews.