Greater London · England
External Mastic in Kew
External mastic in Kew from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Movement joints with cracked, split or missing sealant
- Plants rooting in failed movement joints
- Joints pointed up with cement by mistake
About our external mastic in Kew
Ground-floor and low-level joints are straightforward to reach. For joints higher up, give us some details of the building and we’ll confirm what access is needed. We work on copings & trims, render & cladding joints and concrete & block, and the jobs we see most are leaking joints around cladding and façade panels and joints with sealant missing in places.
Modern London flats rely on sealed movement joints and cladding joints. Period houses have different weak points, such as gutter joints, trims and the line where an extension meets the old wall, and both kinds of building are found across London.
There’s a 12-month guarantee on every job.
- Place
- Kew (W4, TW9, TW8)
- Wider area
- Greater London
- Cover
- One year on every job
- Quote
- A clear price before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
What affects the cost of external mastic
You’ll get a clear quote before we start. It takes into account:
- Access and height
- The old material and how stubborn it is
- How many areas need sealing
- Any working-time requirements on site
Doing several joints on one visit is generally more efficient than separate visits. You will get one clear quote for the whole job.
Helping us quote
What to tell us when you ask for a quote:
- The address or postcode of the job
- The problem you’ve noticed
- Whether it’s a home or a business
- Whether it has been sealed before
For external mastic in Kew, phone 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and you’ll get a clear quote before we start.
Keeping the joints in good condition
Good habits help new joints last longer. Our tips:
- Show decorators and builders where the movement joints are
- Keep water from gutters off the wall
- Have failed joints looked at early
- Clear growth from the base of walls and joints
Only paint over the joint if we’ve confirmed the sealant can take paint. Many exterior sealants are not designed to be painted.
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 so early resealing is worth it.
What happens on the day
We work through the job in order: protection first, then preparation, sealing and a tidy-up. For most jobs that takes a few hours for a handful of joints, longer for a whole elevation. In Kew, 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.
- We take out the old sealant until the faces are sound.
- 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
- Let us know about stairs, lifts or work at height
- For business premises, tell us about site rules or sign-in
- Try not to wet indoor joints just before the visit
Get a quote
For a quote, call 0345 464 0079 or email us with the location and a short description of the problem. We will send you a clear quote before any work starts.
Related advice
Signs you need external mastic in Kew
Using the wrong sealant is another common reason. A stiff, general-purpose sealant cannot cope with a joint that moves a lot, and it tears off the sides.
The most common problems we see are:
- Joints with sealant missing in places
- Moss and dirt in joints with no sealant left
- Water getting into walls through failed joints
- Rigid filler in a joint that should flex
As a London address, Kew can be tricky for parking: let us know about parking bays, permits or a driveway.
What your quote should include
- Is the old sealant removed completely?
- Whether you can choose the colour
- What product goes in the joint
- Whether they’re fully insured
Your questions about external mastic in Kew
I let a flat near Chiswick station. Can you help?
Yes, rental work is part of what we do. You can ring 0345 464 0079 or email us with the address and a few details, and we’ll give you a fixed price before work begins.
Is parking a problem for a job in Kew?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly.
Why do you put foam in the joint first?
That’s backing rod, a closed-cell foam. It stops the sealant going in too deep and bonding to three sides so it can flex with the joint.
Can I do it myself?
That depends on the joint. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional, while a short indoor joint may be within reach.
Is the work guaranteed?
Yes. All our work carries our 12-month guarantee.
Where do you work from?
Mr Mastic is based in Crawley. Our applicators cover Kew, along with the rest of our area.
Can I add another job to the visit?
Yes. Just list everything you need and we’ll quote it together.
Can new sealant go over the old?
No, and we never do. It can look neat for a few weeks, but the new layer lifts away from the old one. The old sealant has to come out completely.
External mastic in Kew: local notes
Historic houses like Kew Palace (about 0.7 miles west) are a reminder that the area around Kew has older buildings as well as new. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Homes close to St Paul's Church include some older properties, and older walls, gutters and the joints where extensions meet them need a flexible sealant. For site and facilities teams at buildings such as Grove Park Primary School, larger buildings have long runs of movement joint that eventually need resealing.
Kew is about 2 miles south of Acton, in Greater London. If you need external mastic in Kew, it’s easy to get a quote: please call 0345 464 0079 or email us. We’re based in Crawley and cover Greater London, Kew included. 764 places in Greater London are on our list. Our London page covers work nearby.
Work in W4, TW9 and TW8 works the same way as everywhere else we cover. That includes homes and businesses on Kew Road, Maze Road and Kent Road and the roads around them. With the A3000 close by, Kew is easy for our applicators to reach. We also cover the places around Kew: Strand-on-the-Green (1 mile north), Grove Park (1 mile east), North Sheen (1 mile south), Gunnersbury (1 mile north) and Turnham Green (1 mile east). Further out, we also cover London (8 miles east), City of Westminster (6 miles east), Marylebone (6 miles north-east), Kensington (3 miles east), St Pancras (7 miles north-east) and Shoreditch (9 miles east).
Around Kew
In Kew, that means homes and buildings near Library for Iranian Studies, Kew Green and Chiswick School. Also close by are Kew College Prep (within half a mile south-west) and Bull's Head pub (less than half a mile north). For rail, the closest station is Chiswick station, roughly 0.5 miles south-east. Nearby you’ll also find Livat Hammersmith (2.2 miles east) and Barnes Hospital (1.5 miles south-east). For a walk, there’s Kew Gardens Lake and Duke's Hollow.
DIY sealant or a professional job?
A DIY attempt does not rule out a professional job. We remove it and do the joint properly, so tell us about it when you ask for a quote.
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
Work for landlords, hotels and businesses
Letting agents and landlords in Kew can book us as well as householders. Resealing between tenancies keeps a property looking cared for before the next move-in.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance that we can handle for you.
Other services in Kew
How the job changes by surface
Cladding and façade panels
Where a cladding system has its own specified sealant, we follow it or an approved alternative. Tell us what the building has when you get in touch.
Brickwork movement joints
Brick moves with heat and moisture, and grows a little over time. That movement goes into the joint, so its sealant has to stay flexible.