Greater London · England
Window & door mastic in Barnehurst, Greater London
Mastic around window and door frames, sills and patio doors for householders, landlords and businesses in Barnehurst. Fully insured, ARBOMaster approved and guaranteed for a year.
- Gaps left after new windows were fitted
- Cold air getting in at the frame edge
- White mastic on grey or black frames
Window mastic for homes and businesses in Barnehurst
Over two decades of sealing frames has taught us which products suit which walls. We’re fully insured ARBOMaster approved applicators, and we give a 12-month guarantee on the work. We work on uPVC windows, window sills and timber windows & doors, and common reasons people get in touch are a bead that doesn’t match the frame and draughts coming in around windows and doors.
London has a lot of flats and conversions, where windows are often on upper floors. In a converted house or block, the lease normally says who is responsible for the windows, so it’s worth checking before booking.
All our work is covered by a one-year guarantee, wherever you are in Greater London.
- Where
- Barnehurst (DA7, DA1, DA8)
- Wider area
- Greater London
- Cover
- One year on every job
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
DIY versus a professional finish
Some sealant jobs are within reach of a careful DIYer, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Sealing over old silicone is the commonest DIY error. Silicone doesn’t stick to old silicone, so it peels away and traps moisture behind it. All the old material has to come out first.
Signs you need window mastic in Barnehurst
Mastic ages in the weather. UV light hardens the outside of the bead, until it loses its stretch and starts to crack.
Most people get in touch when they notice something like this:
- Black, perished sealant on frames
- Rushed sealant from a window installation
- Mastic that has split away from the wall
- Rain getting in at the frame or under the sill
Homes close to Church of St Paulinus include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Comparing quotes
- Who does the work, and how experienced they are
- Which sealant they’ll use, and why
- How hidden problems are handled
- How the joint is cleaned and prepared
Also near Barnehurst
Also in Barnehurst
What window mastic looks like in Barnehurst
In a converted house or block, who looks after the windows depends on the lease, so check that before booking. With historic houses such as Hall Place and Gardens (about 1 mile south-west) nearby, there’s older building stock in the area around Barnehurst as well as newer homes. Where a home is older, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic.
As a London address, Barnehurst can be tricky for parking: tell us about permits, visitor bays or off-street space when you book. Schools such as Mayplace Primary School are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages.
Barnehurst is about 3 miles east of Welling, in Greater London. Wherever you are in the DA7 postcode area, we cover window mastic for homes and businesses. Our Greater London coverage runs to 764 places, Barnehurst among them. For nearby work, see our London page.
Every address in DA7, DA1 and DA8 is within our area for window mastic, from the main roads to the quietest streets. You’ll find streets such as Old Road, Grove Road and Manor Road, and we cover them all. With the A2000 close by, Barnehurst is simple for us to get to. Close by, we work in Bexley Riverside (1 mile north), Northumberland Heath (1 mile north), Crayford (1 mile south-east), North End (1 mile east) and Barnes Cray (1 mile east). We also work in nearby towns such as London (12 miles west), City of Westminster (14 miles west), Marylebone (14 miles west), St Pancras (13 miles west), Shoreditch (12 miles north-west) and Walthamstow (12 miles north-west).
Around Barnehurst
Typical jobs here are in homes near St Catherine's Catholic School, St Catherine's Catholic School and Braeburn Park, among other places. The closest station to Barnehurst is Barnehurst station, about 0.5 miles north-west of the centre. Other landmarks nearby include Stone Castle (4.8 miles east) and Bexley Museum (1 mile south). The countryside around Barnehurst includes Wansunt Pit.
How we quote for window mastic
You will get a clear quote before any work starts. It’s based on:
- When we can work, for business premises
- Mould in or behind the old joints
- How much old sealant there is and how hard it is to remove
- The type of sealant required
Combining jobs into one visit normally makes better use of the time than several visits. You’ll get one clear quote for the whole job.
What we need to know
Photos by email are helpful but not essential. Please mention:
- Access, such as stairs, a lift or height
- Where the property is
- A few photos by email, if you can
- The type of property
We quote each job on its own, so the first step is telling us about yours. Just ring 0345 464 0079 or email us with the details and send photos if you have them.
Why deal with it now?
The work is quick compared with the damage it prevents: it takes anything from an hour or two to a full day, depending on how many frames there are. Leave it until water is coming in and you may need plastering and decorating as well. In a London flat, a failed joint rarely stays your problem alone: water can reach the neighbours below, and gaps in fire-rated joints affect the whole building.
Rather than a set price list, we look at what your job involves: the amount of work, the old material and the access. You’ll know the price before we begin.
Why choose Mr Mastic in Barnehurst
- More than 20 years in sealant work
- Fully insured
- Experience in homes, commercial sites and hotels
- We never seal over old sealant
See what affects the cost and our reviews.
How the job changes by surface
uPVC windows
Plastic frames move a lot between a hot afternoon and a cold night, so the joint needs a low-modulus sealant that stays flexible. White is the usual colour, with brown, anthracite grey and black for coloured frames.
Timber windows & doors
Where timber has rotted at the joint, it needs repairing first. We will point out any rot we find, as a joiner will need to deal with it.
Work for landlords, hotels and businesses
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance that we can handle for you.
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
Questions from Barnehurst
Is Barnehurst in your area for window mastic?
Yes, Barnehurst is within the area we cover. We work across London and the South East. Just phone 0345 464 0079 or send us an email with a few details of the job.
Is parking an issue for window mastic in Barnehurst?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly.
Can you quote for more than one area?
Yes. Tell us about everything you’d like done and we will quote it together.
What should I tell you?
Tell us what needs doing and where, plus photos if you have them. We will ask anything else we need to know.
Are you insured?
Yes. We’re fully insured, and we’ve been doing sealant work for more than 20 years.
Do you seal inside as well as outside?
Yes. Inside, the joint between frame and plaster is sealed neatly, using a paintable sealant if you want to decorate.
Will the old sealant be removed?
Yes. All of the old material is cut out and the joint cleaned.
Do I have to be there?
It depends on the job. Inside work needs someone to give us access, and for outside work we’ll agree access with you when we book.
The process
Good joint work is mostly preparation, and we do not rush it. Joints are cleaned back and dried before anything new goes in. All told, the work takes a morning for a couple of windows and a door. In a London area like Barnehurst, the main things to plan are parking and access: tell us about permits, visitor bays or off-street space, which floor we are working on and whether there’s a lift.
- Each frame is looked over and we agree which ones need resealing.
- The old mastic is cut out and scraped back to clean surfaces.
- Where the gap is deep, backing rod goes in first.
- 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
- Let us know about stairs, lifts or work at height
- Tell us about any water getting in
- Clear the area around the work
Getting a quote
Asking for a quote is easy: let us know the job and the location, and roughly how big it is. A few pictures by email make the job easier to understand, and we’ll come back to you with a quote.