Kent · England
Knave's Ash External Mastic
Professional external mastic in and around Knave's Ash, with every bit of old sealant taken out first and a 12-month guarantee.
- Panel joints letting water in
- Plants rooting in failed movement joints
- Gaps where render, brick and frames meet
Aftercare tips
A little care helps the new joints last. Our advice:
- Look over the joints every year, ideally after winter
- Leave the joints unpainted unless we have said otherwise
- Avoid pressure-washing directly into sealant joints
- Make sure movement joints aren’t pointed over
Only paint over the joint if we have confirmed the sealant can take paint. Many exterior sealants are not designed to be painted, and paint can crack as the joint moves.
An open movement joint lets rain into the wall every time it pours. Over time it can mean damp inside, stained render or frost-damaged brick which cost more to put right than the joint.
About our external mastic in Knave's Ash
For buildings in Knave's Ash, we reseal external joints of all kinds, from brick movement joints to cladding panels. Every joint gets the same careful preparation: clean, sound faces and a controlled depth. If you have joints where the bead has come unstuck and weathered mastic that no longer stretches, we can help.
Outside joints can only be sealed when they’re dry, so work in Knave's Ash is booked around the forecast. Let us know about access to every wall, plus any garages or outbuildings.
Big or small, you get the same 12-month guarantee in Knave's Ash and across Kent.
- Where
- Knave's Ash (CT3)
- Region
- Kent
- Guarantee
- 12 months on all our work
- Quote
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
How it works
Good joint work is mostly preparation, so that’s where we spend the time. Joints are cleaned back and dried before anything new goes in. In total, it normally takes a few hours to a few days, depending on the length of joint and the access. Somewhere as small as Knave's Ash, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- We start by walking round the building and agreeing the joints and the access.
- We cut out the old mastic and rake out anything in the joint.
- Joint faces are cleaned back and primed if the sealant needs it.
- Backing rod sized to the joint goes in to set the depth.
- We apply the sealant, tool it and check the whole run.
Preparing for the visit
- Tell us about access, such as stairs, a lift or high-level joints
- Where the joints are inside, avoid wetting them before we arrive
- Clear the area around the work
Get a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and add pictures by email if you can.
Read more
Can I do it myself?
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it lifts and traps water and mould underneath. All the old material has to come out first.
Quotes for external mastic in Knave's Ash
For a quick quote, just ask. What matters most is:
- The number of rooms or windows
- Whether the work is at height
- The product the joint needs
- Whether there’s mould to deal with
Every job is a little different, so each one gets its own quote. Size, access and the product the joint needs all play a part.
Asking for a quote
When you contact us, it’s useful to know:
- What’s wrong with the joints now
- If someone has resealed it before
- How we’d reach the joints
- The address or postcode of the job
Quotes start with a quick conversation. Describe the problem, the location and the size of the job. Whenever you are ready, ring 0345 464 0079 or drop us an email.
Work for landlords, hotels and businesses
Whether it’s one flat or a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
Different surfaces, different methods
Render joints
Rendered walls have joints at beads, openings and changes of material. We reseal them with a flexible exterior sealant that suits the render colour.
Concrete and blockwork
Big joints in concrete need careful depth control. We size the backing rod to the gap.
Why it’s worth doing now in Knave's Ash
Resealing a run of joints in one go is generally better than patching one at a time. They’ve weathered the same way and it means sorting access once. In a small place like Knave's Ash, homes can be exposed to wind and rain, which finds any gap, and damp in older walls is slow to dry out.
A few things move the cost up or down: the old material and how easily it comes out, any mould to treat, and whether we need extra access for height. Your quote takes all of that into account.
Why us?
- Neat joints and a tidy finish
- Rated 4.9 stars on Google
- We never seal over old sealant
- 12-month guarantee on every job
Take a look at our cost guide and what customers say.
Questions from Knave's Ash
Can you help a landlord with a rental near Herne Bay station?
Yes, rental work is part of what we do. Just call 0345 464 0079 or email us and tell us about the property, and we will send you a clear quote.
Does the coastal weather in Knave's Ash affect outside sealant?
Near the sea, outside joints face more wind, rain and salt than they would inland, so the choice of sealant and the preparation matter even more. Walls facing the sea are normally the first to need attention.
Which products do you use?
Products from Arbo and Everbuild, among others, chosen to suit the joint. We explain the product when we quote.
Do you work for hotels and businesses?
Yes. Commercial and hotel work is a large part of what we do. We can talk about working times when we quote.
Is it worth trying it myself?
Sometimes. The key is preparation: remove all the old material and work on a clean, dry joint. We can always put it right if it fails.
Will it make a mess?
Very little: the area around the joints is protected first, and we tidy up before we go.
Will the new joint stand out?
The sealant colour is picked to suit the wall. There’s a wide choice of exterior colours.
Can a movement joint be filled with mortar?
No, not where the gap is a movement joint. Filling it with mortar defeats its purpose, and the wall may crack nearby. We’ll reseal it with a flexible sealant.
More services for Knave's Ash
What external mastic looks like in Knave's Ash
Knave's Ash is within about 3 miles of the coast, and homes near the sea take more wind-driven rain, with salt in the air closer to the shore. That’s hard on movement joints and outside wall joints, especially on the side facing the sea. London and the South East are among the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Letting a property close to Herne Bay station? Then outside joints that have cracked can let damp into a rental, so check them between lets. In the older streets around Church of the Holy Cross, older walls, gutters and the joints where extensions meet them need a flexible sealant. Schools such as Hoath Primary School are buildings too, and movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Knave's Ash is about 2 miles south of Herne Bay, in Kent. Wherever you are in the CT3 postcode area, our applicators can take on external mastic. We cover 922 towns and villages across Kent. You can also see our page for Chelmsford, about 40 miles away.
Postcode districts we cover here for external mastic: CT3. Streets in the area include Hicks Forstal Road and Hoath Road, and we cover them all. Nearby, we also carry out external mastic in Hoath (1 mile east), Maypole (1 mile north-east), Old Tree (1 mile north-east), Millbank (1 mile north-east) and Hicks Forstal (1 mile west). Within a short drive, we also cover Canterbury (5 miles south-west), Margate (10 miles east), Dover (15 miles south-east), Ramsgate (11 miles east), Broadstairs (12 miles east) and Whitstable (5 miles west).
Landmarks near Knave's Ash
Locally, jobs take us to homes and businesses close to Curtis Wood and Spires Academy, among other places. The closest station to Knave's Ash is Herne Bay station, about 2.6 miles north-west. Well-known places in the area include St Martins Hospital (4.4 miles south-west). For a walk, there’s West Blean and Thornden Woods.