Greater London · England
Window & door mastic in Whetstone, Greater London
Specialist window mastic for Whetstone: the right sealant, proper preparation and a neat finish. Ask us for a quick quote.
- Gaps between the frame and the inside reveal
- A bead that does not match the frame
- Cracked or shrunken mastic around the frame
Window mastic in Whetstone
Colour matters on a frame. White, brown, anthracite grey, black and clear sealants are all available, so the bead blends with the window rather than framing it. We work on timber windows & doors, uPVC windows and patio & French doors, and people most often call us about rain getting in at the frame or under the sill and untidy mastic left by window fitters.
London’s Victorian and Edwardian terraces were built with timber sash windows, and many still have them or their replacements. Either way, the mastic between frame and brickwork is what stops draughts and rain getting in, in Whetstone as anywhere.
We stand behind the work with a 12-month guarantee, so you are covered after we’ve gone.
- Location
- Whetstone (N12, N20, N11)
- Region
- Greater London
- Guarantee
- One year on every job
- Quotes
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Questions from Whetstone
Can you do window mastic in Whetstone?
Yes, Whetstone is within the area we cover. We work across London and the South East. Just ring 0345 464 0079 or email us with a few details of the job.
I let a flat near Oakleigh Park station. Can you help?
Yes, we work for letting agents and landlords. Just phone 0345 464 0079 or send us an email and tell us about the property, and we will send you a clear quote.
Can I do it myself?
That depends on the joint. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional, while a short indoor joint may be within reach.
Do you guarantee window mastic?
Yes. Each job is covered for 12 months, inside or out.
Is it OK to seal over old sealant?
No. New silicone will not bond to old silicone, and it traps any mould or water underneath. We remove it all first.
Can you do the inside joint as well?
Yes. Plenty of draughts come through the inside joint as well as the outside, so sealing both is often worthwhile.
Will new mastic stop draughts?
It will if the frame joint is the problem. We find where the air is coming from before we reseal.
Can you reach windows above the ground floor?
Yes, where they can be reached safely. Tell us about access when you get in touch and we will plan for it.
Places near Whetstone
What else we do in Whetstone
How to look after the new joints
So the new joints stay in good condition:
- Don’t paint over the silicone
- Keep timber frames painted
- Clear any debris from frame drain holes
- Wipe condensation off the frames
Check the drainage slots in the frames are not blocked, so water can run away instead of sitting against the joint.
Water trapped behind a failed joint can start rot in timber frames and sills. Once wood has rotted, it needs repair before it can be sealed, so it pays to reseal before that happens.
Landlords, agents and businesses in Whetstone
Whether it’s one flat or a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
Water getting past a failed joint can damage the building, which matters even more when someone else lives there. Keeping joints in good order is simple maintenance that we can handle for you.
What window mastic looks like in Whetstone
In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking. Rainfall in the South East is lower than in much of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
If you look after a building such as Queenswell Infant & Nursery School, larger buildings have plenty of frames, and the mastic around each one ages. Homes close to Church of St John include some older properties, and the joint between an old wall and a newer frame is generally the first place rain gets in. If you let a flat or house near Oakleigh Park station, cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets.
Whetstone is about 7 miles north of St Pancras, in Greater London. Whether you are in the middle of Whetstone or further out, we cover window mastic for every kind of property, from flats and houses to offices and hotels. Whetstone is one of 764 towns and villages in Greater London we cover. For nearby work, see our London page.
Work in N12, N20 and N11 is quoted and booked the same way as anywhere else. Streets in the area include High Road, Swan Lane and Dene Road, and we cover them all. Main roads around Whetstone include the A1000, so getting to you is simple. If you’re just outside Whetstone, we cover Oakleigh Park (1 mile west), North Finchley (1 mile south), Woodside Park (1 mile south-west), East Barnet (1 mile north-east) and Brunswick Park (1 mile east). We also work in nearby towns such as London (9 miles south), City of Westminster (8 miles south), Marylebone (8 miles south), Kensington (9 miles south), St Pancras (7 miles south) and Shoreditch (8 miles south-east).
Near you in Whetstone
We work in homes and buildings around Finchley Catholic High School, Francis Skaryna Belarusian Library and Museum and Woodhouse College and the streets around them. Other local landmarks include Three Horseshoes pub (within half a mile north-west) and Swan Lane Open Space (under half a mile west). For rail, the closest station is Oakleigh Park station, roughly 0.8 miles north. Other landmarks nearby include Grand Arcade (0.9 miles south) and Francis Skaryna Belarusian Library and Museum (0.9 miles south-west). For a walk, there’s Highgate Hill and Barfield Allotments Nature Park.
How we quote for window mastic
We quote each job individually. These are the things that affect it:
- How many rooms, windows or areas are involved
- How much old sealant there is and how hard it is to remove
- The type of sealant required
- Access and height
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote.
Helping us quote
There’s no need for technical detail. Just tell us:
- Whether it has been sealed before
- A few pictures by email, if you can
- How many joints, rooms or windows are involved
- What the problem is, such as mould, gaps, leaks or cracking
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we’ll explain how we’d tackle it. Whenever you’re ready, ring 0345 464 0079 or send us an email.
How the job changes by surface
Patio & French doors
Door frames take knocks and movement every time the doors are used. A flexible sealant copes with that, where a rigid one would crack.
Aluminium frames
Metal frames expand in the sun and are often slim, with little room for error. A neat, narrow bead in a colour to match keeps the clean look.
Can I do it myself?
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
When it isn’t the sealant
Sealant is not the answer to every problem, and we’d rather say so up front. Sealant will not put right:
- Condensation trapped between the panes
- Penetrating damp from a failed cavity tray or render
- Rotten timber, which needs a joiner first
Not sure which it is? You can call 0345 464 0079 or email us and we’ll tell you honestly before booking.
What we seal
- Composite doors
- Timber windows & doors
- Patio & French doors
- Window sills
- uPVC windows
- Aluminium frames
How the visit works
All our tools and materials come with us in the van, so there’s nothing for you to buy. Once we’ve agreed what’s being done, the area is protected and the work begins. It normally takes most of a day for a typical house, less for a few frames. In Whetstone, 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.
- We start by checking each window and door with you.
- Next the failed sealant is cut away and the joint cleaned.
- Where gaps are deep, backing rod goes in first.
- We apply a weatherproof sealant to match the frame and tool it neatly.
- We clear up and check every joint is fully closed.
Getting ready for the visit
- Let us know if you’ve seen damp or leaks
- Keep pets and children clear of the area while we work
- Tell us if parking is tricky
Ask for a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints.