Greater London · England
External Mastic in Hanwell
Our applicators work in Hanwell on sealing brickwork movement joints, render, cladding and façade joints. Old material cut out, joints cleaned and sealed neatly.
- Sealant that has lost its bond to the brick or render
- Gaps where render, brick and frames meet
- Joints with sealant missing in places
External mastic in Hanwell
Joints in render and cladding are easy to overlook until a damp patch appears. We inspect them, agree which need doing and reseal with a weatherproof, flexible sealant in a matching colour. If you have movement joints with cracked, split or missing sealant and failed seals between different materials, we can put it right, whatever the surface.
Modern London flats rely on sealed movement joints and cladding joints. Older terraces have their own weak points: gutter joints, roofline trims and the joint where an extension meets the original wall, and both kinds of building are found across London.
Every job comes with our one-year guarantee.
- Place
- Hanwell (W7, W13, UB2)
- Wider area
- Greater London
- Cover
- One year on every job
- Price
- A clear price before we start
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Hanwell questions
Is parking an issue for external mastic in Hanwell?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. That way the visit can be planned around it.
I let a flat near Hanwell station. Can you help?
Yes, rental work is part of what we do. You can phone 0345 464 0079 or drop us an email with the address and a few details, and we will give you a fixed price before work begins.
What is a movement joint?
Most straight vertical gaps in brickwork are movement joints. It lets the bricks expand without cracking, and it should be sealed with a flexible sealant.
Is it OK to fill a movement joint with cement?
No. Rigid materials cannot move with the wall and the joint fails. Where a joint has been mortared, it can often be raked out and sealed properly.
Where is Mr Mastic based?
We work from Crawley. We cover Hanwell and the rest of Greater London, along with the rest of our area.
How long does external mastic take?
It depends on the size of the job, but most jobs take anything from a few hours to several days, depending on the building. We’ll give you a better idea when we quote.
Do you do commercial work?
Yes, regularly. Larger jobs can be planned room by room or area by area.
When is the sealant fully cured?
Cure times vary by product and the temperature. Before we leave, we will tell you the cure time.
Signs you need external mastic in Hanwell
Poor preparation causes many early failures: dusty or wet faces, no primer where one was needed, or old sealant left in. The new sealant then lets go long before it should.
The problems people generally mention when they call are:
- Leaking joints around cladding and façade panels
- Joints where the bead has come unstuck
- Movement joints filled with mortar instead of sealant
- Moss and dirt in joints with no sealant left
As a London address, Hanwell can be tricky for parking: let us know about parking bays, permits or a driveway.
Comparing quotes
- Are they insured?
- What happens if the job turns out different
- Whether the sealant suits the joint
- What the quote includes, VAT included or not
Work for landlords, hotels and businesses
Letting agents often deal with us directly. Tell us the address, the job and how access works and we will quote.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance that we can handle for you.
Places near Hanwell
What else we do in Hanwell
What external mastic looks like in Hanwell
With historic houses such as Pitzhanger Manor (about 1.3 miles east) nearby, there’s older building stock in the area around Hanwell as well as newer homes. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth. London terraces and converted houses often share gutters, downpipes and walls, so check who is responsible for the outside before booking.
For an older house near a landmark such as Church of St Mellitus, older walls, gutters and the joints where extensions meet them need a flexible sealant. Managing a site like St Joseph's Catholic Primary School? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Hanwell is about 1 mile west of Ealing, in Greater London. For external mastic in and around Hanwell, it’s easy to get a quote: please phone 0345 464 0079 or email us. We cover Greater London from our Crawley base, Hanwell included. Our area takes in 764 places across Greater London, large and small. You can also see our page for London, roughly 10 miles from Hanwell.
Postcode districts we cover here for external mastic: W7, W13 and UB2. Local streets include Park Road, Green Lane and Felix Road. Being close to the A4001, Hanwell is simple for us to get to for external mastic. Close by, we work in West Ealing (1 mile west), Ealing (1 mile east), Dormers Wells (1 mile north-west), South Ealing (1 mile south-east) and Pitshanger (2 miles north-east). Within a short drive, we also cover London (10 miles east), City of Westminster (8 miles east), Marylebone (8 miles east), Kensington (6 miles east), St Pancras (10 miles east) and Shoreditch (11 miles east).
Local landmarks in Hanwell
Typical jobs here are in homes near Drayton Manor High School, Cuckoo Schools and Drayton Green. There’s a railway station in Hanwell itself: Hanwell station. Well-known places in the area include Ealing Hospital (within half a mile west) and Gunnersbury Park House - Large Mansion (2.3 miles east). The countryside around Hanwell includes Middle Lake and Castlebar Hill.
DIY versus a professional finish
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and doesn’t move well, and getting the depth right matters as much as the look.
Sealing over old silicone is the commonest DIY error. Silicone doesn’t stick to old silicone, so it peels away and traps moisture behind it. All the old material has to come out first.
What affects the quote in Hanwell
We quote each job individually. These are the things that affect it:
- Any mould that needs treating
- How many areas need sealing
- Working hours on commercial sites
- Whether the work is at height
A failed joint rarely gets cheaper to fix by waiting, because water and mould keep working on it. If you’re unsure, phone 0345 464 0079 or email us and we will give you an honest view and a quote.
What we need to know
You do not need to know the technical terms. It helps if you can tell us:
- Whether it has been sealed before
- The type of property
- Access, such as stairs, a lift or height
- How many joints, rooms or windows are involved
For external mastic in Hanwell, phone 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.
Different surfaces, different methods
Render joints
Cracks along render joints let water in behind the coat. A sound joint keeps the render dry behind.
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.
What we do, step by step
When we arrive, we start by going over the job with you, so there are no surprises. We protect the surfaces around the joints before any work begins. Most jobs take anything from a few hours to several days, depending on the building. For a job in Hanwell, parking and access are the things to plan: let us know about parking, the floor we’ll be working on and any lift or shared entrance.
- We inspect the joints and agree which need resealing and how they’ll be reached.
- Old sealant and any debris are cut and raked out.
- Both sides are cleaned back to sound material and primed if needed.
- Backing rod goes in next, setting the depth and keeping the sealant off the back of the joint.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
Getting ready for the visit
- Mention any sign-in or site rules at work premises
- Let us know about earlier repairs to the joints
- Tell us about access, such as stairs, a lift or high-level joints
Getting a quote
We quote each job on its own. Just phone 0345 464 0079 or drop us an email with the details and send pictures if you have them.
Read more
Keeping the joints in good condition
No joint lasts for ever, but care makes a real difference. Our tips:
- Ask before painting over external sealant
- Walk round the building once a year and look at the joints
- Show decorators and builders where the movement joints are
- Keep movement joints as flexible joints, not mortar
Follow the cure time we give you before the joint is knocked or disturbed. The surface skins over quickly, but full cure takes longer.
Water getting behind cladding or render can go unnoticed for a long time. By the time there’s a damp patch, the damage can be well established.