Greater London · England

Window & door mastic in Mill Hill, Greater London

Mastic around window and door frames, sills and patio doors for Mill Hill, backed by a one-year guarantee. Ask us for a quote.

  • Untidy mastic left by window fitters
  • Mastic that is falling out in pieces
  • Gaps between the frame and the inside reveal

Window mastic in Mill Hill

How we handle window mastic in Mill Hill

Homes in Mill Hill have every kind of window: uPVC, aluminium, timber and composite, plus patio doors, French doors and sills. The sealant is chosen to suit the frame material and the wall. If you are dealing with water coming in at the bottom corners of a door and mastic that has split away from the wall, we can help, whatever the surface.

From mansion-block windows to modern glazing in new flats, London has every kind of frame. Over the years, the sealant around them shrinks, cracks and pulls away, which is when draughts and damp patches appear in homes in Mill Hill.

Each job carries a 12-month guarantee.

Mr Mastic applicator sealing the top of a white uPVC door frame on a red-brick house
Location
Mill Hill (NW7, N20)
Wider area
Greater London
Guarantee
One year on every job
Quote
A clear quote up front
Phone
0345 464 0079
Page updated
26 October 2026

When something else is needed

Some problems need a builder, plumber or other trade rather than us:

  • Faulty window hardware
  • Condensation trapped between the panes
  • Penetrating damp from a failed cavity tray or render

Not sure which it is? You can call 0345 464 0079 or send us an email and we’ll tell you honestly before you book.

Surfaces we seal

  • Aluminium frames
  • Patio & French doors
  • Composite doors
  • Timber windows & doors
  • Window sills
  • uPVC windows

How to look after the new joints

Once the sealant has cured, a few habits help it last:

  • Repaint timber before it’s bare
  • Clear any debris from frame drain holes
  • Check the mastic once a year
  • Don’t paint over the silicone

Wipe the frames with soapy water when you clean the windows, and avoid solvent cleaners on the sealant.

Signs to watch for: split or missing mastic, gaps, damp patches inside or black mould on the reveal. Any of these is worth a call.

Window mastic in Mill Hill: local notes

Historic houses like Heath Hall (about 4 miles south-east) are a reminder that the area around Mill Hill 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. In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking.

For an older house near a landmark such as St Paul's Church, the joint between an old wall and a newer frame is generally the first place rain gets in. Mill Hill is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book. Schools such as St Paul's CofE Primary School NW7 are buildings too, and its window and door frames need their mastic kept sound, just like a home’s.

Mill Hill is about 1 mile north-east of Burnt Oak, in Greater London. Homes, rented property, offices and hotels in Mill Hill is covered for window mastic, old or new, large or small. The work is guaranteed for a year. Across Greater London, we cover 764 places, and Mill Hill is one of them. London is on our list too, about 10 miles from Mill Hill.

We work across the NW7 and N20 postcode area for window mastic. If you need window mastic at a property on Daws Lane, Byron Road and High Street or anywhere close by, our applicators can take on the job. Other places close to Mill Hill include The Hale (1 mile west), Burnt Oak (1 mile south-west), Grahame Park (1 mile south), Totteridge (2 miles north-east) and Edgware (2 miles west). We also work in nearby towns such as London (10 miles south-east), City of Westminster (8 miles south-east), Marylebone (8 miles south-east), Kensington (8 miles south), St Pancras (8 miles south-east) and Shoreditch (9 miles south-east).

Landmarks near Mill Hill

Around Mill Hill, our work takes us to homes and buildings near Mill Hill School, Copthall School and Bittacy Hill Park. You’ll also find Francis Skaryna Belarusian Library and Museum (2 miles east) and Rising Sun pub (0.7 miles north-west). The nearest railway station is Mill Hill Broadway station, about 1 mile south-west of the centre. Other landmarks nearby include Broadwalk Centre (2 miles west) and Francis Skaryna Belarusian Library and Museum (2 miles east). Green spaces nearby include The Mill Field and Darland's Lake.

Map of Mill Hill © OpenStreetMap contributors

Questions from Mill Hill

Is Mill Hill in your area for window mastic?

Yes, Mill Hill is within the area we cover. We work across London and the South East. Just call 0345 464 0079 or drop us an email with a few details of the job, and we will send you a clear quote.

Do you work for landlords with property near Mill Hill Broadway station?

Yes, landlords and agents are among the people we work for, and several properties can be quoted together. You can ring 0345 464 0079 or drop us an email with the details for a clear quote.

When is the sealant fully cured?

Different products cure at different speeds, so please follow the time we give you when we finish.

Are you an approved applicator?

Yes. We are approved under the ARBOMaster scheme.

Which products do you use?

Quality sealants from brands including Arbo and Everbuild, chosen to suit the joint. We explain the product when we quote.

Is the work guaranteed?

Yes. Every job comes with our 12-month guarantee, and we are ARBOMaster approved applicators.

Can you do upstairs windows?

Yes, where it’s safe. Higher or awkward frames may need extra access, and we will confirm what’s needed.

Can new window sealant be painted?

Not if it’s silicone. Tell us your decorating plans and we will pick a sealant to suit.

Work for landlords, hotels and businesses

In hotels, rooms out of use cost money, so the work can be planned room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.

Landlords and letting agents in Mill Hill can book us as well as householders. Sealant work between tenants keeps a property looking cared for before the next move-in.

DIY versus a professional finish

Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.

Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.

Surface by surface

uPVC windows

Some uPVC windows were sealed at fitting with a quick bead that never bonded. It comes out, deep gaps get backing rod and the joint is resealed.

Patio & French doors

Not every patio door leak is a mastic problem: worn seals, blocked drainage slots or a poor threshold detail can be the cause. We look for the cause first.

What we do, step by step

All our tools and materials come with us in the van. Once we have agreed what’s being done, we protect the area and start. Most jobs take a few hours for a few frames, or a day or more for a whole house. In Mill Hill, flats, stairs and shared entrances are part of the routine. Mention any building rules, key holders or managing agents when you book.

  1. We check how each frame can be reached safely.
  2. All the failed sealant is cut away, along with any loose debris.
  3. The surfaces are cleaned and left dry, and primed where the sealant calls for it.
  4. Deep voids are backed, then the sealant is gunned in.
  5. The joint is shaped to shed water and the area tidied.

Getting ready for the visit

  • Mention any leaks or damp you’ve noticed
  • Move anything stored near the joints
  • Let us know about stairs, lifts or work at height

How to get a quote

For a quote, call 0345 464 0079 or email us and tell us where the job is and what the problem looks like. You’ll have a clear quote before any work starts.

Ask for a quote

Read more

Why deal with it now?

A quick bead over the top of old mastic looks like an easy fix, but it will not grip old, dirty sealant. It soon lifts and the leak carries on behind it. The old mastic has to come out. In a London flat, a failed joint rarely stays your problem alone: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.

There are no prices on our website, because the cost depends so much on the job itself. Call for a quick quote and we’ll talk you through it.

Why Mill Hill clients choose us

  • Sealant colour chosen to suit
  • A choice of colours where the product allows
  • Arbo and Everbuild products
  • Rated 4.9 stars on Google

Read our cost guide or customer reviews.

20+ yearsMastic and sealant specialists
ARBOMaster approvedApproved applicator for Arbo sealants
Fully insuredDomestic, commercial and hotels
One-year guaranteeOn every job