Greater London · England
South Harefield Window Mastic
Mastic around window and door frames, sills and patio doors in South Harefield, with a one-year guarantee on every job. Call for a quick quote.
- Cracked or shrunken mastic around the frame
- Gaps between the frame and the inside reveal
- Gaps left after new windows were fitted
Window mastic in South Harefield, done properly
Colour matters on a frame. White, brown, anthracite grey, black and clear sealants are all available, so the line suits the frame instead of standing out. We work on timber windows & doors, uPVC windows and composite doors, and people most often call us about black, perished sealant on frames and water coming in at the bottom corners of a door. Mr Mastic is a mastic company, not a general handyman, so window mastic in South Harefield is done by someone who does this every day.
London homes have every kind of window, from timber sashes in period terraces to aluminium and uPVC in newer blocks. The mastic around them dries out and cracks with age, which is when draughts and damp patches appear in homes in South Harefield.
You get a 12-month guarantee, the same in South Harefield as everywhere else we work.
- Place
- South Harefield (UB9)
- Wider area
- Greater London
- Cover
- One year on every job
- Price
- A clear price before work begins
- Call
- 07833 053749
- Last updated
- 26 October 2026
Frames and glazing around South Harefield
With historic houses such as Ickenham Hall (about 2.7 miles south-east) nearby, there’s older building stock in the area around South Harefield as well as newer homes. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic. In London conversions and blocks, the lease decides who is responsible for the frames, so check that before booking.
Letting a property close to Denham station? Then cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets. For site and facilities teams at buildings such as Harefield Infant School, the mastic around its windows and doors needs looking after like any other building’s. As a London address, South Harefield can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
South Harefield is about 3 miles west of Ruislip, in Greater London. Our applicators cover window mastic for homes and businesses in South Harefield and nearby, as part of our work across Greater London. Our area takes in 786 places across Greater London.
Every address in UB9 is covered for window mastic. Window mastic is available to properties on Peerless Drive, Truesdale Drive and Priory Avenue and the roads around them. Nearby, we also carry out window mastic in Newyears Green (1 mile south-east), Denham (2 miles south), New Denham (3 miles south), Ickenham (3 miles south-east) and Ruislip Manor (3 miles east). Further out, we also cover City of Westminster (15 miles east), Marylebone (15 miles east), Kensington (14 miles south-east), Hampstead (13 miles east), Brompton (15 miles south-east) and Ealing (9 miles south-east).
What’s near South Harefield
Around South Harefield, our work takes us to homes and buildings near The River Garden pub, The Harefield Academy and The Green, among other places. For rail, the closest station is Denham station, about 1 mile south-west. Other landmarks nearby include The Pavilions (3 miles south) and Hillingdon Museum and Archives Services (3.1 miles south). For a walk, there’s Horse Shoe Bay and Dews Farm Sand Pits.
Common questions in South Harefield
Do you cover South Harefield for window mastic?
Yes, South Harefield is within the area we cover. We work across London and the South East. You can phone 07833 053749 or send us an email and let us know what needs doing.
I let a flat near Denham station. Can you help?
Yes, we work for landlords and letting agents. You can call 07833 053749 or email us with the address and a few details, and we’ll give you a fixed price before any work starts.
Can you seal the gap between the frame and the plaster indoors?
Yes. The outside joint keeps the weather out, and the inside joint stops draughts and finishes the reveal. We can do either or both.
How much does window mastic cost in South Harefield?
Every job is different, so each one gets its own quote. To get one, call 07833 053749 or email us with a short description of the job.
Do you remove the old sealant?
Yes. We cut out all the old sealant and clean the joint.
Can resealing stop a draught around my window?
Often, yes. Air often gets in between the frame and the wall, and sealing the inside and outside joints closes that path.
Where do you work from?
We’re based in Crawley, West Sussex, and we cover South East England, London and all of Scotland.
Can you get sealant to suit coloured frames?
Yes, in most cases. Tell us the frame colour when you get in touch and we will match it as closely as we can.
How we quote for window mastic
Call for a quick quote. What matters most is:
- The product the joint needs
- How many rooms, windows or areas are involved
- Any mould that needs treating
- Working hours on commercial sites
What it costs depends on how much there is to do, how much old material has to come out and access to the work. We give a clear quote before work begins, so you know where you stand.
Helping us quote
To help us quote quickly, let us know:
- How we’d reach the joints
- A few photos by email, if you can
- The rough size of the job
- Where the property is
Every job is quoted individually, so the first step is telling us about yours. Just call 07833 053749 or email us with the details.
Towns and villages near South Harefield
What else we do in South Harefield
How the job changes by surface
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 we pay close attention there.
Window sills
Sills catch the water running down the glass, so the joints at each end and underneath matter. Each is cleaned out and resealed.
Leave it or put it right?
Choosing the product is half the job. Interior caulk and bathroom silicone aren’t made for exterior frame joints. A low-modulus exterior sealant keeps its stretch through hot and cold weather. Converted houses in London often have a bathroom above someone else’s living room, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Putting it right early is much less trouble for homes in South Harefield.
Every job is a little different, so each one gets its own quote. Size, access and the product the joint needs all play a part.
What you get with us
- Anti-fungal silicone where joints get wet
- White, clear, grey or coloured to suit, where the product allows
- Colour agreed with you before work begins
- Quality sealants from Arbo and Everbuild
Read our cost guide or what customers say.
How to look after the new joints
Looking after new joints is easy, and it makes a real difference:
- Clear any debris from frame drain holes
- Paint up to the joint, not over it
- Ventilate rooms so frames don’t stay wet inside
- Use gentle cleaners on frames and sealant
Clean the frames with mild soapy water, and avoid solvent cleaners on the sealant.
Water gets in quietly when mastic fails. You might not see it until plaster blows or a damp patch appears inside. Catching it early keeps the fix to a reseal.
DIY versus a professional finish
If you are set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.
If you’ve already had a go yourself, that’s fine. We remove it and do the joint properly, so tell us about it when you ask for a quote.
What we cannot put right
We won’t take on work that will not last, so here’s what sealant can’t put right:
- A failed sealed unit that has misted up
- Draughts through the window seals rather than the frame
- Soft or decayed wood in the frame
Not sure which it is? You can phone 07833 053749 or drop us an email and we will tell you honestly.
Where we work in South Harefield
- Timber windows & doors
- Patio & French doors
- uPVC windows
- Window sills
- Aluminium frames
- Composite doors
How the visit works
You do not need to clear the whole room or building, only the area right around the joints. Everything nearby is protected, and the work takes a few hours for a handful of frames, longer for a whole house in most cases. In South Harefield, as in most of London, parking needs a little planning. A visitor permit or a nearby bay makes the visit run more smoothly.
- 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.
- We apply a weatherproof sealant to match the frame and tool it neatly.
- Every joint is checked before we leave.
Getting ready for the visit
- Keep pets and children clear of the area while we work
- Tell us if parking is tricky
- Move anything stored near the joints
How to get a quote
Need a quote? Please phone 07833 053749 or email us with a few details. You will know what we plan to do, and what it will cost, before any work begins.