Kent · England
Sand mastic for sash & case windows in Northfleet Green, Kent
Sand mastic in Northfleet Green from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Mastic round period door frames that has failed
- Patchy fillers round a sash window
- Gaps between timber frames and stone or brick
About our sand mastic in Northfleet Green
Burnt sand mastic is a traditional material blends with stone and brick surrounds. It’s a good fit for period properties where a modern sealant bead would stand out. We work on sash and case windows, stone surrounds and brick reveals, and common reasons people get in touch are patchy fillers round a sash window and draughty sash windows at the surround.
Somewhere as small as Northfleet Green, older homes often have timber frames set in stone or brickwork. Older buildings like these do not always suit modern silicone, so the sealant has to be chosen to suit the building.
A one-year guarantee comes as standard, so you are not left on your own once the job is done.
- Location
- Northfleet Green (DA13, DA11)
- Region
- Kent
- Cover
- One year on every job
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
How the visit works
We bring everything the job needs with us. Once we have agreed what’s being done, the area is protected and the work begins. It normally takes anything from a few hours to a full day, depending on how many windows. Somewhere as small as Northfleet Green, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- We check each window surround and the condition of the joint.
- We rake out the old mastic and clean the joint.
- Large voids are packed out.
- We point the joint with sand mastic by hand.
- We finish the mastic to a tidy line.
How to prepare
- Tell us about any water getting in
- Clear items away from the joints we are working on
- Mention any sign-in or site rules at work premises
How to get a quote
Getting a quote is simple: let us know what needs doing and where. Photos by email help us understand the job.
Advice
DIY sealant or a professional job?
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
The biggest DIY mistake is sealing over old sealant. 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.
Signs you need sand mastic in Northfleet Green
Paint, silicone or cement used over old mastic causes problems. They don’t suit the joint and we normally remove them.
People generally contact us when they notice something like this:
- Tired mastic found when preparing windows for paint
- Gaps round a timber door in stone or brick
- Open joints round the window box
- Silicone on a period window that looks wrong
If you live in an older home near Church of St Nicholas, the joint between an old wall and a newer frame is usually the first place rain gets in.
What your quote should include
- What preparation is included
- How long to leave it before use
- Which sealant they’ll use, and why
- How much experience the applicator has
What affects the cost of sand mastic
We quote each job individually. This is what makes a difference:
- The type of sealant required
- The number and length of the joints
- Whether the work is at height
- Whether there’s mould to deal with
A few things move the cost up or down: how much old sealant there is and how stubborn it is, any mould to treat, and whether we need extra access for height. We take all of that into account in your quote.
What we need to know
To make quoting easier, please include:
- The rough size of the job
- Any previous sealing or DIY work
- Where the job is, and your postcode
- Whether it’s a home or a business
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints.
How the job changes by surface
Timber door frames
Round a period front door, sand mastic gives the right look.
Stone surrounds
Old stone surrounds are often uneven, so the gap isn’t the same all the way round. Sand mastic is shaped by hand to suit.
Towns and villages near Northfleet Green
More services for Northfleet Green
Your questions about sand mastic in Northfleet Green
Will you come out to Northfleet Green?
Yes, Northfleet Green is covered. We work across London and the South East, and smaller places are part of that. The journey is planned ahead, so it helps to know about access.
I let a flat near Ebbsfleet International station. Can you help?
Yes, we work for landlords and agents. You can phone 0345 464 0079 or email us with the address and a few details, and we’ll give you a fixed price before we start.
What do you put in the joint?
Quality sealants from brands including Arbo and Everbuild, chosen to suit the joint. We’ll tell you what we are using and why.
How long will you be here?
A typical job takes a few hours for a single window, longer for several, including the preparation. We’ll confirm how long when we quote.
Is it worth trying it myself?
Some simple jobs can be done by a careful DIYer. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
Is it messy?
Tidy work is part of the job. We protect what’s around the joints.
Do you work for hotels and businesses?
Yes. We have worked for hotels, offices and other businesses and we are fully insured.
Is it possible to paint over sand mastic?
Sand mastic is normally left unpainted, as guidance on traditional windows advises. Ask us before decorating.
Windows and doors in Northfleet Green
Historic houses like Cobham College (about 3.2 miles south-east) are a reminder that the area around Northfleet Green has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. 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.
Managing a site like Painters Ash Primary School? Then larger buildings have plenty of frames, and the mastic around each one ages. For landlords with property near Ebbsfleet International station, any sash windows need sound mastic to keep draughts and rain out.
Northfleet Green is about 1 mile south of Northfleet, in Kent. If you need sand mastic in Northfleet Green, it’s easy to get a quote: please phone 0345 464 0079 or email us. We are based in Crawley and cover Kent. Northfleet Green is one of 922 places in Kent where we work. There’s also a page for London, roughly 19 miles from Northfleet Green.
Postcode districts we cover here for sand mastic: DA13 and DA11. That includes homes and businesses on Downs Road and New Barn Road. Close by, we work in Southfleet (1 mile west), Painters Ash (1 mile north), Istead Rise (1 mile south-east), Hook Green (1 mile west) and Springhead (1 mile north). We also work in nearby towns such as Maidstone (13 miles south-east), Dartford (5 miles west), Sevenoaks (11 miles south-west), Tonbridge (15 miles south), Swanley (7 miles west) and Kings Hill (10 miles south).
Near you in Northfleet Green
Locally, jobs take us to homes and businesses close to Black Lion pub, Northfleet School for Girls and Saint George's Church of England School. Northfleet Green’s nearest station is Ebbsfleet International station, roughly 2 miles north. Other landmarks nearby include Gravesham Museum (2.3 miles north-east) and Bluewater (3.3 miles north-west). Open spaces near Northfleet Green include Sawyers Lake.
Looking after it afterwards
Looking after new joints is easy:
- Renew mastic before redecorating the windows
- Go gently near the mastic when preparing windows
- Avoid patching sand mastic with silicone
- Check the mastic when you check the paintwork
Leave the new mastic alone while it firms up. It forms a skin fairly soon, but takes longer to harden fully.
Gaps round a sash box let in draughts and rain. The longer it’s left, the more the joint opens.
Landlords, agents and businesses in Northfleet Green
We also work for property managers and facilities teams in Northfleet Green and across Kent. Several sites can go on one quote, and we’re fully insured.
For anyone letting property in or around Northfleet Green, several properties can go on one quote. Send us the addresses and the work at each, and photos by email help.