Greater London · England
Window & door mastic in Greenhill, Greater London
Mastic around window and door frames, sills and patio doors in Greenhill, with a 12-month guarantee on every job. Call for a quick quote.
- Black, perished sealant on frames
- Leaking joints at the ends of sills
- Rushed sealant from a window installation
What we do, step by step
On the day, there’s very little for you to do. Show us the job and we’ll take it from there. The job generally takes a few hours for a few frames, or a day or more for a whole house. In Greenhill, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- First, we go round the frames with you and agree the list.
- The old mastic is cut out and scraped back to clean surfaces.
- Deep gaps get closed-cell backing rod to set the depth.
- A flexible exterior sealant is applied in a colour to suit the frame.
- Every joint is tooled smooth and checked before we leave.
Preparing for the visit
- Clear the area around the work
- Keep pets and children clear of the area while we work
- Tell us about any previous sealing or DIY attempts
Get a quote
For window mastic in Greenhill, call 0345 464 0079 or email us. A short description of the job and where it is helps us quote, and we will agree the price before any work begins.
Advice
How we handle window mastic in Greenhill
The mastic around a window or door seals the gap between the frame and the wall. 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 have a bead that doesn’t match the frame and damp patches on the reveal after heavy rain, we can put it right, on patio & French doors, window sills and composite doors alike.
Much of London’s older housing was built with timber sash windows, some still in place and some long since replaced. Whatever is in the opening now, the joint between frame and wall is what keeps the weather out, in Greenhill as anywhere.
Whatever the size of the job, you get the same one-year guarantee.
- Where
- Greenhill (NW3, NW6)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Quote
- A clear price before work begins
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
What window mastic looks like in Greenhill
The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. With historic houses such as 2 Willow Road (about 0.3 miles north-east) nearby, there’s older building stock in the area around Greenhill 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.
Managing a site like The Royal School? Then larger buildings have plenty of frames, and the mastic around each one ages. For an older house near a landmark such as Rosslyn Hill Unitarian Chapel, the joint between an old wall and a newer frame is normally the first place rain gets in. Greenhill is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Greenhill is about 1 mile north-east of Hampstead, in Greater London. We provide window mastic to homes and businesses in Greenhill and nearby. We cover 764 towns and villages across Greater London.
Jobs for window mastic in NW3 and NW6 works the same way as everywhere else we cover. Local streets include Back Lane, Well Road and Ornan Road, all of which we cover. Other places close to Greenhill include Hampstead (1 mile south-west), Vale of Health (1 mile north), West Hampstead (1 mile west), Fortune Green (1 mile west) and Haverstock (1 mile south-east). Within a short drive, we also cover London (5 miles south-east), City of Westminster (3 miles south), Marylebone (3 miles south-east), Kensington (4 miles south), St Pancras (3 miles south-east) and Shoreditch (5 miles south-east).
Near you in Greenhill
In Greenhill, that means homes and buildings near Cecil Sharp House, Fitzjohn's Primary School and King William IV Public House and the streets around them. Nearby too are South Hampstead High School (0.6 miles south) and Hampstead Heath (0.7 miles north-east). There’s a railway station in Greenhill itself: Hampstead Heath station. Nearby you will also find New End Hospital (within half a mile north-west) and Montfichet's Tower (4.3 miles south-east). Green spaces nearby include Belsize Wood and Parliament Hill.
Surface by surface
Composite doors
Front doors take the weather head on, and the top and bottom corners tend to fail first. We pay most attention there.
Patio & French doors
Door frames take knocks and movement every time the doors are used. The sealant must cope with it, where a rigid one would crack.
Aftercare tips
Simple care keeps the joints in good condition. Our advice:
- Don’t aim a pressure washer at the joints
- Paint up to the joint, not over it
- Check the mastic once a year
- Clear any debris from frame drain holes
Silicone cannot normally be painted, so if you’re planning to paint the frames or walls, tell us beforehand. 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. Resealing closes it.
Landlord and commercial work in Greenhill
We also work for businesses, from offices to washrooms and kitchens. For commercial premises, we can talk through working times when we quote.
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements and we will give you a quote.
Honest limits
Sealant isn’t the answer to every problem, and we will tell you before work begins. Sealant will not put right:
- Misting between the panes of a double-glazed unit (that needs a new unit)
- A door that needs adjusting, rehanging or new seals
- A frame that has rotted at the joint
If you’re not sure, just phone 0345 464 0079 or drop us an email and we’ll give you a straight answer.
Joints and surfaces we work on
- Composite doors
- Timber windows & doors
- Aluminium frames
- Window sills
- uPVC windows
- Patio & French doors
Places near Greenhill
More services for Greenhill
Questions from Greenhill
Is parking an issue for window mastic in Greenhill?
Parking in Greenhill, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly, so mention what’s available when you book.
Can you help a landlord with a rental near Hampstead Heath station?
Yes. We work for landlords and agents as well as homeowners. You can phone 0345 464 0079 or email us with the details for a clear quote.
Do you hold any approvals?
Yes. We are ARBOMaster approved, the scheme for applicators of Arbo sealants.
Can you get sealant to suit coloured frames?
Normally, yes. Tell us the frame colour when you get in touch and we’ll match it as closely as we can.
Should I try DIY first?
For a simple, easy-to-reach joint, a careful DIYer can do a reasonable job. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
Do the sealants smell?
Some sealants have a smell while they cure, which fades as it sets. Ventilation helps.
Do you cover Greenhill?
We do. Greenhill is part of the area we cover.
Is the new sealant paintable?
That depends on the product. Silicone is not paintable, but some hybrid sealants are. Mention any painting plans before any work starts.
What affects the quote in Greenhill
For a quick quote, just ask. The main things that affect it are:
- The old material and how stubborn it is
- Whether the work is at height
- Any mould that needs treating
- The product the joint needs
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please ring 0345 464 0079 or email us.
What we need to know
What to tell us when you ask for a quote:
- The rough size of the job
- What the problem is, such as mould, gaps, leaks or cracking
- The address or postcode of the job
- If it’s domestic, commercial or a hotel
Every job is quoted individually. Simply call 0345 464 0079 or email us and describe the job, and pictures are welcome.
Should I try it myself first?
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
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.