Kent · England
External Mastic in Knatts Valley
Sealing brickwork movement joints, render, cladding and façade joints for householders, landlords and businesses in Knatts Valley. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Sealant pulling away from one side of the joint
- Movement joints filled with mortar instead of sealant
- Panel joints letting water in
What happens on the day
We bring everything the job needs with us. Once we’ve agreed what’s being done, the area is protected and the work begins. It normally takes anything from a few hours to several days, depending on the building. For a village or hamlet like Knatts Valley, the journey is planned in advance: let us know about lanes, gates and parking. We bring what the job needs, so it can be finished in one trip where possible.
- 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.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Before we arrive
- For business premises, tell us about site rules or sign-in
- Mention any leaks or damp you’ve noticed
- Mention if the joints have been sealed before
Ask for a quote
For external mastic in Knatts Valley, phone 0345 464 0079 or send us an email. Tell us what the problem is and where, and you will get a clear quote before work begins.
Related advice
External mastic in Knatts Valley
Getting the depth right is half the job. Backing rod controls how deep the sealant goes and keeps it off the back of the joint, leaving it bonded to two faces so it can move with the wall. We work on façade panels, joints between brick and frames and brickwork movement joints, and people most often call us about moss and dirt in joints with no sealant left and leaking joints around cladding and façade panels.
In a village or hamlet like Knatts Valley, older cottages and farm buildings often stand in the open, so walls and rooflines take the full force of wind and rain. Gutter joints and wall joints there need a sealant that can flex and stay put.
Every job comes with a 12-month guarantee, wherever you are in Kent.
- Location
- Knatts Valley (TN15)
- Region
- Kent
- Guarantee
- 12 months on all our work
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Keeping the joints in good condition
Simple care keeps the joints in good condition. We recommend:
- Leave the joints unpainted unless we’ve said otherwise
- Check external joints each spring
- Show decorators and builders where the movement joints are
- Clear growth from the base of walls and joints
Keep pressure washers away from the sealant. A strong jet can damage the edges of the bead and let water in behind.
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.
Can I do it myself?
What a professional job adds is preparation and the right product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
Work for landlords, hotels and businesses
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we will give you a quote.
We work for landlords and agents as well as homeowners. Sealant work between tenants keeps a property looking cared for.
Your questions about external mastic in Knatts Valley
Do you work for landlords with property near Kemsing station?
Yes, landlords and agents are among the people we work for. You can phone 0345 464 0079 or email us with the details for a clear quote.
Can you do external mastic in Knatts Valley?
Yes. Our work covers London and the South East, and Knatts Valley is part of that. Just ring 0345 464 0079 or send us an email with a few details of the job, and we will give you a clear quote.
Can you match the colour of my brickwork?
The sealant colour is picked to suit the wall, so the joint sits quietly in the wall. There’s a wide choice of exterior colours.
When will the joints need doing again?
It depends on the exposure, the movement and the product. Treat it as a maintenance item and look at it yearly and reseal when it splits.
Does someone need to be in?
It depends on the job. For work indoors, someone needs to let us in, and for outside work we will agree access with you when we book.
Is there a guarantee?
Yes. All our work carries a 12-month guarantee.
Can you quote for more than one area?
Yes. Just list everything you need and we’ll quote it together.
What does external mastic cost?
It depends on the job, so we quote each one individually. To get one, call 0345 464 0079 or email us and let us know what needs doing and where.
What the job involves on each surface
Cladding and façade panels
Cladding and façade panels are usually separated by sealed joints. Each joint gets a sealant that suits the panel and its movement.
Joints between dissimilar materials
Where a frame or panel meets masonry, water often finds a way in. We cut out the old sealant and reseal with a product suited to both surfaces.
What we can’t put right
A few problems are outside what sealant work can do:
- Cutting new joints into brickwork, which is building work rather than sealant work
- Failed render or damaged cladding panels
- Rising or penetrating damp from elsewhere in the wall
Not sure which it is? You can ring 0345 464 0079 or email us and we will tell you honestly.
What we seal
- Brickwork movement joints
- Façade panels
- Copings & trims
- Joints between brick and frames
- Render & cladding joints
- Concrete & block
What external mastic looks like in Knatts Valley
Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. Historic houses like Lullingstone Castle (about 2.8 miles north-west) are a reminder that the area around Knatts Valley 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.
Rented homes near Kemsing station change hands often, and split movement joints are easy to miss on a rental until damp shows inside. Homes close to Church of Saint Mary the Virgin include some older properties, and older walls, gutters and the joints where extensions meet them need a flexible sealant. Schools such as West Kingsdown CofE VC Primary School are buildings too, and movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Knatts Valley is about 4 miles north-east of Sevenoaks, in Kent. Our applicators cover external mastic for homes and businesses in Knatts Valley and nearby. Knatts Valley is one of 922 places in Kent we cover. London is on our list too, around 19 miles away.
Postcode districts we cover here for external mastic: TN15. Streets in the area include Knatts Lane and Knatts Valley Road, and we cover them all. We also cover East Hill (1 mile north-west), Woodlands (1 mile south), Romney Street (1 mile west), West Kingsdown (1 mile north-east) and Cotman's Ash (1 mile south). Within a short drive, we also cover Maidstone (13 miles east), Dartford (8 miles north), Sevenoaks (4 miles south-west), Royal Tunbridge Wells (14 miles south), Gravesend (9 miles north-east) and Tonbridge (9 miles south).
What’s near Knatts Valley
Locally, jobs take us to homes and businesses close to Kemsing Down and the streets around them. Knatts Valley’s nearest station is Kemsing station, roughly 2.5 miles south of the centre. Other landmarks nearby include Sevenoaks Hospital (3.9 miles south-west) and Kemsing Castle Bank (2 miles south-west).
Nearby places to Knatts Valley
More services for Knatts Valley
How we quote for external mastic
We don’t publish a price list, because jobs vary so much. What we look at:
- Any working-time requirements on site
- The old material and how stubborn it is
- The number of rooms or windows
- Whether the work is at height
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.
What we need to know
The more you tell us, the more accurate the quote. When you ask for a quote, tell us:
- If someone has resealed it before
- Any access issues, like height or stairs
- What’s wrong with the joints now
- How many joints, rooms or windows are involved
Asking for a quote is easy: let us know what needs doing and where. Photos by email help us understand the job.