Kent · England
Northfleet Window Mastic
We cover Northfleet for mastic around window and door frames, sills and patio doors. Old material cut out, joints cleaned and sealed neatly and a one-year guarantee.
- Damp patches on the reveal after heavy rain
- Draughty joints inside around the window
- Cracked sealant at the sill ends
How we handle window mastic in Northfleet
Every window and door frame has a gap around it, and mastic is what closes it. When it cracks, hardens or pulls away, draughts and rain get in. The old mastic is removed and the joint resealed with a flexible exterior sealant. If you’re dealing with cracked sealant at the sill ends and rain getting in at the frame or under the sill, we can help.
In a town like Northfleet, the windows on the most exposed side of a house take the brunt of the rain, so the mastic there tends to fail first. It’s worth looking at every frame, not just the one that leaks.
A one-year guarantee comes as standard, so you’re covered after we’ve gone.
- Place
- Northfleet (DA11)
- Region
- Kent
- Cover
- A year, on every job
- Quotes
- A clear price before work begins
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
When it is not the sealant
A few problems are outside what sealant work can do:
- Broken hinges, locks or handles
- A frame that has rotted at the joint
- Worn gaskets, brush seals or a door that has dropped
If you’re not sure, just ring 0345 464 0079 or drop us an email and we’ll give you a straight answer.
What we seal
- Patio & French doors
- Aluminium frames
- Timber windows & doors
- uPVC windows
- Composite doors
- Window sills
Window mastic in Northfleet: local notes
Northfleet is close to the coast, where wind-driven rain is a fact of life and, nearer the shore, so is salt air. Both are hard on the mastic around window and door frames, which can dry out and crack sooner where a building faces the weather. With historic houses such as Cobham College (about 3.7 miles south-east) nearby, there’s older building stock in the area around Northfleet as well as newer homes. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window.
If you look after a building such as Northfleet Technology College, the mastic around its windows and doors needs looking after like any other building’s. For an older house near a landmark such as Church of All Saints, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Northfleet is about 5 miles east of Dartford, in Kent. We carry out window mastic for homes and businesses in Northfleet and the surrounding area, as part of our work across Kent. Our Kent coverage runs to 922 places, and Northfleet is one of them. London is on our list too, about 20 miles from Northfleet.
Here we cover the DA11 postcode area for window mastic. Local streets include Lawrance Square, London Road and Marks Square, all of which we cover. With the A2 and A226 close by, Northfleet is easy for our applicators to reach. Close by, we work in Painters Ash (1 mile south-west), Springhead (1 mile west), Windmill Hill (1 mile east), Northfleet Green (1 mile south) and Gravesend (1 mile east). Larger places within reach include Maidstone (14 miles south-east), Dartford (5 miles west), Sevenoaks (13 miles south-west), Swanley (8 miles west), Kings Hill (11 miles south) and Foley Park (13 miles south-east).
Near you in Northfleet
In Northfleet, that means homes and buildings near The Six Bells pub, Saint George's Church of England School and Copperfield Academy, among other places. The nearest railway station is Gravesend station, about 1 mile north-east of the centre. A little further out are Bluewater (3.3 miles west) and Stone Castle (3.1 miles west). The countryside around Northfleet includes Chafford Gorges Nature Park and Sawyers Lake.
Places near Northfleet
What else we do in Northfleet
Common problems we fix in Northfleet
Joint shape matters as much as the product. A skim of sealant over a wide gap soon tears, and a gap filled solid cannot flex. Backing rod sets the right depth.
Keep an eye out for any of the following:
- Cracked or shrunken mastic around the frame
- Untidy mastic left by window fitters
- Sealant in the wrong colour for the frame
- Mastic that’s falling out in pieces
If you let a flat or house near Gravesend station, cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets.
What to look for in a quote
- How the joint is cleaned and prepared
- What the cure time is
- Is VAT in the price?
- What insurance they hold
Aftercare tips
Good habits help new joints last longer. Our tips:
- Clear any debris from frame drain holes
- Paint up to the joint, not over it
- Avoid harsh chemicals near the mastic
- Keep paint and stain on wooden frames in good order
Most silicone sealants won’t take paint, so mention any painting plans before we start. There are paintable sealants for joints that need it.
A small gap around a frame only grows. As the old mastic shrinks further, more air gets through, and a cold room gets colder. A new joint closes it up.
Landlords, agents and businesses in Northfleet
For anyone letting property in or around Northfleet, jobs at different addresses can go on one quote. Send us the addresses and the work at each.
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. We have worked in hotels as well as homes and businesses.
What happens on the day
On the day, there’s very little for you to do. Show us the job and we will take it from there. The job generally takes a morning for a couple of windows and a door, including the tidy-up. Parking in a town like Northfleet is normally straightforward, but tell us if there’s a driveway or any restrictions, and let us know if the work is upstairs, in a flat or up high outside.
- We start by checking each window and door with you.
- We remove the old mastic and clean the frame and the wall.
- We fit backing rod in deep gaps so the sealant is the right depth.
- New exterior sealant goes on in a matching colour and is tooled smooth.
- Every joint is checked before we leave.
How to prepare
- Mention if the joints have been sealed before
- Tell us about access, such as stairs, a lift or high-level joints
- Keep pets and children clear of the area while we work
Getting a quote
Need a quote? Please ring 0345 464 0079 or send us an email with a few details. You will know what we plan to do, and what it will cost, before any work begins.
Advice
Should I try it myself first?
If you are set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
Some sealant jobs are within reach of a careful DIYer, 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.
What affects the quote in Northfleet
Some jobs are bigger than they look, and some smaller. What affects the quote:
- The number of rooms or windows
- Whether old sealant or filler has to be cut out
- The size of the job
- Mould in or behind the old joints
Homes and businesses are quoted the same way: how much there is to do, how we reach it and what it needs. Call for a quick quote and we will go through it with you.
Asking for a quote
A few details help us give you an accurate quote. When you ask for a quote, tell us:
- Pictures of the joints, sent by email
- Whether it’s a home or a business
- Where the property is
- Access, such as stairs, a lift or height
Getting a quote is simple: let us know what needs doing and where. Photos by email help us understand the job, and we’ll take it from there.
Your questions about window mastic in Northfleet
Is Northfleet in your area for window mastic?
Yes. Our work covers London and the South East, and Northfleet is part of that. Just ring 0345 464 0079 or send us an email with a few details of the job.
Can you help a landlord with a rental near Gravesend station?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. You can call 0345 464 0079 or email us with the details for a clear quote.
Are you fully insured?
Yes. Full insurance covers our work.
Can you match the sealant to my frames?
Yes. We can use white, brown, anthracite grey, black or clear, so the joint suits the frame.
Can you seal over the old sealant?
No. New silicone will not bond to old silicone, and it traps any mould or water underneath. We remove it all first.
What information do you need?
A short description and the location, with pictures by email if possible. If we need more, we will ask.
Will it make a mess?
We keep the work tidy. Nearby surfaces are protected, and we clear up when we are done.
Can new window sealant be painted?
Silicone generally will not take paint. If you plan to paint, tell us first and we can use a paintable sealant where it suits the joint.