Kent · England
Window Mastic in Longfield
Mastic around window and door frames, sills and patio doors for homes and businesses in Longfield and across Kent. Fully insured, ARBOMaster approved and guaranteed for a year.
- Draughts coming in around windows and doors
- Gaps between the frame and the inside reveal
- Rain getting in at the frame or under the sill
Window mastic in Longfield
Every window and door frame has a gap around it, and mastic is what closes it. Once that seal fails, wind and rain find the gap. The old mastic is removed and the joint resealed with a flexible exterior sealant. We work on timber windows & doors, composite doors and aluminium frames, and common reasons people get in touch are draughty joints inside around the window and draughts coming in around windows and doors.
Homes in small places like Longfield often stand in the open, with little to shelter their windows from wind and rain. That exposure dries out and cracks the mastic around frames and sills faster.
A one-year guarantee comes as standard, so you are not left on your own once the job is done.
- Location
- Longfield (DA3)
- Wider area
- Kent
- Cover
- A year, on every job
- Price
- A clear price before we start
- Call
- 0345 464 0079
- Updated
- 26 October 2026
How the job changes by surface
Aluminium frames
Bi-fold and sliding aluminium doors have long frame joints, and the threshold joint takes a lot of water. Each is cleaned, backed where deep and resealed.
Patio & French doors
The joints around patio doors run a long way, top, sides and threshold. The threshold and the bottom corners take the most water, so they get particular care.
Longfield questions
Is Longfield within the area you cover?
Yes, we do. We work across London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Can you help a landlord with a rental near Longfield station?
Yes, rental work is part of what we do. Just phone 0345 464 0079 or send us an email and tell us about the property, and we will give you a clear price.
Does the work come with a guarantee?
Yes, with our one-year guarantee. Keeping drainage clear and checking the joints yearly helps them last.
Can you seal the gap between the frame and the plaster indoors?
Yes, we do both. Indoors, we seal between the frame and the plaster or reveal, using a paintable sealant if you want to decorate.
How long should I leave it?
Cure times vary by product and the conditions. Before we leave, we’ll tell you the cure time.
Do you take out the old sealant first?
Yes. We cut out all the old sealant and clean the joint before applying anything new.
Is the new sealant paintable?
Silicone generally won’t take paint. Let us know beforehand, and we will use a paintable product where it suits.
Can you quote for more than one area?
Yes. Tell us about everything you’d like done.
How we quote for window mastic
Your quote is based on your job. We take into account:
- Whether there’s mould to deal with
- How easy the joints are to reach
- Any working-time requirements on site
- How much old sealant there is and how hard it is to remove
Homes and businesses are quoted the same way: how much there is to do, how we reach it and what it needs, along with when we can work on site. Ask us for a quote and we will go through it with you.
Helping us quote
To help us quote quickly, please include:
- Where the job is, and your postcode
- Pictures of the joints, sent by email
- Whether it has been sealed before
- Whether it’s a home or a business
To get a quote, call 0345 464 0079 or send us an email and tell us where the job is and what the problem looks like. We will give you a clear price before any work starts.
Why deal with it now?
Redecorating is a good moment to renew the mastic. Fresh joints finish the job neatly. Where a wall is exposed, as many are in small places like Longfield, wind-driven rain gets into any failed joint, and damp in older walls is slow to dry out.
What you pay reflects the work, not guesswork. That’s why we ask a few questions first and give you a clear quote before we start.
What you get with us
- Any old sealant cut out fully, not covered over
- You choose the colour before work begins
- ARBOMaster approved applicator
- Neat joints and a tidy finish
Read what affects the cost or our reviews.
Nearby places to Longfield
Also in Longfield
What we are called out for in Longfield
Timber windows bring their own problems. Mastic painted over many times cracks with the paint, and timber moves with moisture as well as temperature.
Look out for these signs:
- Gaps left after new windows were fitted
- Gaps where the sill meets the wall
- Cracked or shrunken mastic around the frame
- Rain getting in at the frame or under the sill
Homes close to Church of Saint Mary Magdalene include some older properties, and replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Comparing quotes
- Who turns up on the day
- The length of the guarantee
- Whether you can choose the colour
- How hidden problems are handled
When it isn’t the sealant
We will not take on work that will not last, so these are the limits:
- Penetrating damp from a failed cavity tray or render
- A door that needs adjusting, rehanging or new seals
- Faulty window hardware
If you are not sure, just ring 0345 464 0079 or email us and we’ll give you a straight answer before booking.
Joints and surfaces we work on
- Window sills
- Timber windows & doors
- Composite doors
- uPVC windows
- Aluminium frames
- Patio & French doors
What happens on the day
We keep the work tidy and contained to the area we are working on. The job usually takes a few hours for a handful of frames, longer for a whole house, and we explain the cure time before we leave. For a village or hamlet like Longfield, the journey is planned in advance: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- First, we go round the frames with you and agree the list.
- We remove the old mastic and clean the frame edge and wall.
- Deep gaps get closed-cell backing rod to set the depth.
- A flexible exterior sealant is applied in a colour to suit the frame.
- We tool each bead neatly and check every joint is closed.
Preparing for the visit
- Tell us about any water getting in
- Keep children and pets away from the work area
- Tell us about access, such as stairs, a lift or high-level joints
Get a quote
The more we know about the job, the more useful the quote. Let us know the location, the problem and roughly how many joints, and email pictures if that is easy.
Related advice
Longfield homes and the weather
The South East is one of the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. Historic houses like Cobham College (about 4 miles east) are a reminder that the area around Longfield 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’s traditional sand mastic.
For landlords with property near Longfield station, renewing tired window mastic between tenants heads off draught and damp complaints. For site and facilities teams at buildings such as Longfield Academy, the mastic around its windows and doors needs looking after like any other building’s.
Longfield is about 3 miles south-west of Northfleet, in Kent. From the centre of Longfield to the outskirts, window mastic is available for homes and businesses alike. Our Kent coverage runs to 922 places, Longfield among them. There’s also a page for London, roughly 19 miles from Longfield.
Our applicators cover all of DA3 for window mastic and the streets around it. Streets in the area include Station Road, Main Road and Ightham Close. We also cover the places around Longfield: Hartley (1 mile south), New Barn (1 mile east), Longfield Hill (1 mile south-east), New Ash Green (2 miles south) and Nash Street (2 miles east). Further out, we also cover Maidstone (13 miles south-east), Dartford (5 miles north-west), Sevenoaks (10 miles south-west), Gravesend (4 miles north-east), Tonbridge (14 miles south) and Northfleet (3 miles north-east).
Local landmarks in Longfield
In Longfield, that means homes and buildings near Railway Tavern, Hartley Primary Academy and Rectory Meadow, among other places. There’s a railway station in Longfield itself: Longfield station. Nearby you’ll also find Darent Valley Hospital (3.3 miles north-west) and Stone Castle (3.4 miles north). The countryside around Longfield includes Sawyers Lake.
Landlord and commercial work in Longfield
If you manage several properties in or around Longfield, several properties can go on one quote. Send us the addresses and the work at each.
Letting agents and landlords in Longfield can book us as well as homeowners. Resealing between tenancies is a simple way to keep a property in good order.